Science method

Meta-Analysis - Science method

Works consisting of studies using a quantitative method of combining the results of independent studies (usually drawn from the published literature) and synthesizing summaries and conclusions which may be used to evaluate therapeutic effectiveness, plan new studies, etc. It is often an overview of clinical trials. It is usually called a meta-analysis by the author or sponsoring body and should be differentiated from reviews of literature.
Questions related to Meta-Analysis
  • asked a question related to Meta-Analysis
Question
1 answer
Hi Researchers
I am doing meta-analysis for one of my SR. Could you please from your expertise suggests if we can do the meta-analysis of RCT and multiarm-RCTs together?
Thank you
Relevant answer
Answer
Hi Preet,
It seems to me that what you are looking for is a network meta analysis.
Since you have multi-arm trials, you probably have multiple treatments and network meta analysis is an extension of meta-analysis to a network of treatments. You can easily find many references for network meta analysis and I just give a review here
It could be that your groups is the same treatment in different dosages or that you would like to combine groups. In this case, have a look at the Cochrane guidance
  • asked a question related to Meta-Analysis
Question
5 answers
Hello ,
I am conducting a meta-analysis on refractive errors using data from 50 observational studies. These studies do not include control groups, as the focus is on descriptive outcomes such as prevalence, mean spherical equivalent, and trends across different populations.
I would greatly appreciate your guidance on the following:
  1. Statistical methods: What is the most appropriate model for pooling prevalence data (e.g., logit transformation vs. Freeman-Tukey double arcsine)?
  2. Handling heterogeneity: With high variability expected across studies (due to different populations, measurement methods, etc.), what strategies would you recommend for subgroup or sensitivity analyses?
  3. Publication bias: How do you address publication bias when the data is prevalence-based rather than effect-size-based?
  4. Software/tools: Are there specific tools (e.g., R packages, CMA, RevMan) that you have found particularly useful for meta-analyses of this nature?
Relevant answer
Answer
Thanks to everyone.
  • asked a question related to Meta-Analysis
Question
2 answers
Dear colleagues,
When selecting dental materials for clinical use, common criteria such as the presence of a Safety Data Sheet (SDS) and certifications like CE (European Conformity) and FDA (U.S. Food and Drug Administration) are often considered essential. However, I believe there might be additional factors worth discussing to ensure safety, quality, and optimal clinical performance.
In your opinion, what other criteria should be considered when choosing dental materials for patients? Have you encountered materials that, despite having necessary certifications, did not perform well in clinical settings?
Some additional factors I propose include:
Biocompatibility: Ensuring no allergic or inflammatory reactions in oral tissues.
Clinical performance and durability: Resistance to wear, discoloration, and thermal expansion in the oral environment.
Absence of harmful substances: For instance, materials free from Bisphenol A (BPA).
Compatibility: With other materials or systems used in dentistry.
Scientific evidence: Backed by peer-reviewed studies and long-term clinical trials.
I am keen to hear your experiences, insights, and any relevant literature or research findings you could share.
Relevant answer
Answer
In the clinical setting all these factors are closely related. Visual requirements and technical possibilities have to be balanced in each clinical situation. Finally, the material fulfilling most of the factors is selected as the material of choice. Thus, the material selection can be compared with a field of tension in which the change of one parameter may affect all other parameters. Currently, no universally applicable material is available.
  • asked a question related to Meta-Analysis
Question
4 answers
Dear researchers,
I have a plan to conduct a meta-analysis of a construct that has five dimensions. Do you think that would be possible? How can I handle the issue that each study considers only one dimension of the construct? Please recommend some references that I can use.
Relevant answer
Answer
Thanks for your comment. If possible, please share any resources or articles that I can use.
  • asked a question related to Meta-Analysis
Question
2 answers
I’ve recently had the opportunity to participate in a systemic review and meta analysis as independent researcher (not affiliated with my University). Who is leading the overall project is telling us that is ok and we don’t have to ask permission to the University to submit the paper however I do feel uncomfortable in doing so. Is anyone else been in my position before or know the technicalities behind the affiliation process in pre-publication stage?
Thank you so much in advance
Relevant answer
Answer
Dear De. Di Sauro,
I've personnaly had a similar experience where I worked with a private research institute and my affiliation was that of the institure, not my university. I've also worked with research groups in other universities and depending on my level of involvement with the groups my affiliation was at times that of the other university's research group instead of my own. My personal experience has been that as long as the people in a research commitee or institute are okay with you using thier affiliation and have given you permission, you should be okay.
As for not using your university affiliation, you are not beholden to the university and can conduct research outside of thier jurisdiction. However, using a university affiliation instead of an indepedant one may have an affect on the handling editors attitude to the paper, as well as peer reviewers. Some journals may also outright reject independant researchers and you should consult submission guidelines. I would suggest using both your university affiliation, as well as the independant affiliation, as most journals allow for 2 affiliations.
Also, if you are using a university affiliation with a specific department or research group in mind, you have to ask them for permission.
  • asked a question related to Meta-Analysis
Question
3 answers
I tried to do meta analysis of single arm studies (without control) using R studio, but I still can't find how to do the pooled analysis. I only have the mean and SD from pre treatment and mean with SD after weeks of treatment. Can I do pooled meta analysis of the single arm studies with continous data from pre and post intervention in R studio?
Relevant answer
Answer
Single-arm meta-analyses comparing pre- and post-intervention outcomes, where the pre-intervention data serve as the control group and the post-intervention data as the experimental group, have been utilized in previous studies. These analyses typically report effect sizes using standardized mean difference (SMD) or mean difference (MD). However, it is recommended to avoid this type of meta-analysis due to the well-documented presence of multiple biases. If such an approach is employed, it is crucial to account for the pre-post correlation to mitigate potential biases. This adjustment can be incorporated using statistical software such as R, with packages like meta or metafor providing the necessary functionality.
For further details on this subject, the following resources are recommended:
  • asked a question related to Meta-Analysis
Question
2 answers
Hello everyone,
I am conducting a meta-analysis to evaluate the efficacy of various PTSD treatments (e.g., Prolonged Exposure Therapy, CPT...) using Comprehensive Meta-Analysis (CMA). For each treatment, I have calculated the within-treatment effect size (Hedges' g) based on pre- to post-treatment or pre- to follow-up changes across multiple studies. I also have the corresponding Q-statistics for each treatment group.
Now, I would like to compare these treatments to determine if there are significant differences in their efficacy. Specifically, I am wondering:
  • Should I focus on comparing the total Hedges' g scores for each treatment?
  • Or should I compare the Q-statistics instead?
  • Alternatively, is there a more appropriate method (e.g., subgroup analysis, meta-regression) within CMA to assess differences across treatment types?
I would greatly appreciate any guidance or suggestions on how to approach this comparison in CMA, and also how to do so.
Thank you!
Relevant answer
Answer
Dear Gelman,
Since Hedges'g is a standardized effect size you can compare its values between treatment arms, yet it could be challenging when the values of two treatment arms are close and overlapping. Subgroup analysis of each treatment and comparison of their effect size with statistical tests such as the Q test may prove useful in such cases.
To do so in CMA define a comparison column and fill it in with the corresponding treatment for each study. It should look like the figure I've attached (Figure 1). Once you run the analyses it will produce a forest plot of all the studies and you need to conduct a subgroup analysis by the type of comparison and you should get sth similar to Figure 2. Comparison of each treatments effect size for your meta-analysis can be done using method 2 or method 3 explained in the CMA handbook (https://meta-analysis.com/download/Meta-analysis%20Subgroups%20analysis.pdf?srsltid=AfmBOor06LWKrtTPnGxpYtyoiWtshTdVDO54zjpPDkouTKM8H2PF1Hq1). The newer CMA software may have implemented these codes into the software, yet I am not aware of such an update and most likely you will have to do it manually using Excel.
If the studies are multi-armed rather than having a single arm, I would recommend a network meta-analysis as it will allow you to compare and rank the treatments, yet it is not possible with CMA.
  • asked a question related to Meta-Analysis
Question
4 answers
Hi all,
I want to conduct a meta analysis and for the first step we identified the corresponding corpus of articles related to the topic/ research theme.
The next step, as far as I understand , is to find all the quantitative contributions. Currently, because it is a fairly well studied theme, there is a total of approximately one thousand articles.
How is it possible to identify all the quantitative contributions in this big list of articles other than downloading the 1k articles and scanning manually through all of them?
Is there a specific method or tool to do that ? I don't think databases such as WOS or Scopus have a specific filter.
thank you in advance for your help!
Relevant answer
Answer
There are some fairly well validated study type filters that can help, for example for RCTs. You can add them into your search strategy. There are also some reasonable AI tools for study type classification.
The normal process for a systematic review/meta analysis would be to download the titles and abstracts of your thousand papers into a software such as EPPI reviewer or covidence or one of the free options and do a 'sift on title and abstract to remove the ones that don't match your population/intervention/control/outcomes that you set out in your protocol. That should reduce the numbers enough that you can order the remainder at full text to check in detail for whether they are includes or not.
  • asked a question related to Meta-Analysis
Question
3 answers
Dear all,
I am currently conducting a meta-analysis using the CMA software and have encountered some SEM studies. I have selected the "Correlation and sample size" option in CMA, and I am entering the path coefficients into the correlation field, while using the study's sample size as the number of participants.
I would greatly appreciate any advice or clarification on whether this approach is correct. Should path coefficients be treated as correlations in this context, or is there a better way to handle SEM data in meta-analysis? Additionally, I was wondering if anyone could point me to any articles that provide detailed guidance on how to enter different types of effect sizes in CMA?
Thank you so much for your time and help!
Relevant answer
Answer
  • asked a question related to Meta-Analysis
Question
2 answers
Please provide a reference if you can. Thank you.
Relevant answer
Answer
The inclusion of papers in a systematic review should not depend on their statistical significance (it may be at high risk of biasing the review). One of the strengths of SRMA is to be able to pool together results independently of their significance findings if they cope with the inclusion criteria.
  • asked a question related to Meta-Analysis
Question
1 answer
Hello everyone,
I am building a cost-effectiveness decision tree, and the probabilities at each node are supposed to come from Relative Risks reported in a meta-analysis. However, I do not have baseline probabilities for each outcome (e.g., treatment success) in the control arm. I know that Odds Ratios can be more directly converted to probabilities, but I want to stay consistent with the meta-analysis data using RR.
  • Are there any recommended methods or assumptions for deriving baseline probabilities when only RRs from a meta-analysis are available?
  • Is it acceptable to approximate these baseline risks using data from alternative sources or expert opinion?
Any guidance or references on handling this scenario would be greatly appreciated.
Thank you in advance!
Relevant answer
Answer
In this situation i think it would be reasonable to use best available estimates of baseline probability (risk) from the literature or from a selection of expert opinions.
  • asked a question related to Meta-Analysis
Question
4 answers
I would like to know if I suspect that two studies (same authors) was based on the same patients but with different follow-up. Can we include both? Can we dowgrade one of them (high risk of bias) to exclude one in a sensitivity analysis? I cannot find any clear answer in the different tools assessing quality of evidence (GRADE, RoBs, ...)
Relevant answer
Answer
The usual thing in these cases is if there is a cohort of patients that have been published at two different times, to avoid bias, only one of the two will be used in the meta-analysis. Generally the one that has a longer follow-up period.
  • asked a question related to Meta-Analysis
Question
4 answers
Is it logical to convert an effect measure given as an ODDs ratio in an article to a Hazard ratio to be pooled in the Meta Analysis given the effect measures in other articles are Hazard ratios?
Relevant answer
Answer
Thank you all for your valuable information.
  • asked a question related to Meta-Analysis
Question
2 answers
Dear Colleagues, Professor Tim Bogg and I are currently conducting a meta-analysis evaluating the associations between dietary behaviors and Big Five/Five-Factor personality traits at Wayne State University. We are seeking relevant unpublished research and conference presentations on this topic, including unpublished data, manuscripts in progress, and/or papers that have been accepted for publication but are not yet in press. Studies that focus on operationally defined “healthy” or “Unhealthy” eating behavior or bivariate correlations between consumption of specific food items (e.g. fruit, meat, sugar) and the Big Five personality traits are welcome! For inclusion in our meta-analysis…
A measure of the Big Five personality traits was used.
Specific food items or well defined food categories
Correlations for the above relationships should either be reported or be able to be computed.
To submit your work for consideration in our meta-analysis, please email paula.harrison@wayne.edu with (a) either a paper describing the study and its results or your raw data, and (b) the reference for your work.
We greatly appreciate any information you are able to share! Please provide any additional contact information in the event that we may need to ask follow-up questions regarding the characteristics of the sample, your measurement approach, or other methodological factors.  Best, Paula Harrison, M.A.
Tim Bogg, Ph.D.
Relevant answer
Answer
Hello, thank you for the information! I will be sure to take a look at this and reach out if I have any questions. I hope you had a wonderful new year!
  • asked a question related to Meta-Analysis
Question
7 answers
I tried to do meta analysis of single arm studies (without control) using R studio, but I still can't find how to do the pooled analysis. I only have the mean and SD from pre treatment and mean with SD after weeks of treatment. Can I do pooled meta analysis of the single arm studies with continous data from pre and post intervention in R studio?
Relevant answer
Answer
The error you're encountering is likely because the n.c (control group sample size) argument is not defined in your dataset. Since you're working with single-arm studies (no control group), you don't need to specify n.c. Iskandar Purba Geraldi
  • asked a question related to Meta-Analysis
Question
7 answers
We performed a meta analysis recently and SAS popped out an i=squared of exactly zero. I know this is theoretically possible but it doesn't make sense to me as the outcomes in the different studies in the analysis did not have the exact same means and variances. Can anyone shed light on this?
Thanking you all in advance for your thoughts.
Gary
  • asked a question related to Meta-Analysis
Question
7 answers
Addressing publication bias is important in a meta-analysis. There are several ways of assessing that, including the funnel plot, Egger's test, and Begg's test. I wonder which approach is preferred or more accurately reflects PB?
Relevant answer
Answer
Publication bias can be assessed through both qualitative and quantitative methods. One common qualitative approach is the inverted funnel plot. This method allows you to visually inspect the distribution of studies. Ideally, studies should be symmetrically distributed around the mean effect size. If asymmetry is detected, it may indicate potential publication bias. However, for a reliable assessment of symmetry, it is generally recommended to have at least 10 studies in your meta-analysis. Fewer studies may result in misleading conclusions due to the limited data available for evaluating funnel plot symmetry.
Quantitative tests are often employed to confirm the findings from the funnel plot analysis. Two commonly used statistical tests for this purpose are Egger’s test and Begg’s test. Egger’s test helps detect small-study effects, which may signal publication bias. It is particularly useful when you suspect that smaller studies are systematically overrepresented in the analysis. On the other hand, Begg’s test is recommended when dealing with smaller sample sizes. It is less sensitive to heterogeneity and provides a robust method for identifying publication bias in situations where the number of studies is limited.
If you identify potential publication bias, there are several approaches to mitigate its impact on your results. One method is to add contour-enhanced lines to the funnel plot. This can help identify regions where missing studies might be influencing the analysis. The addition of these contour lines helps visualize the potential impact of publication bias on the results and shows where the "missing" studies could explain the asymmetry. Another approach is the trim and fill method, which estimates the number of missing studies and predicts where they might fall on the funnel plot. This method also provides an adjusted effect size by taking into account the potential missing studies and assessing the statistical significance of the findings.
Both of these methods can be valuable in correcting for publication bias once it has been detected. However, to further validate your findings and account for the sources of potential bias, consider conducting additional analyses, such as sensitivity analysis, leave-one-out analysis, subgroup analysis, and meta-regression analysis. Sensitivity analysis assesses the robustness of your results by examining how they change when individual studies are removed from the analysis. Leave-one-out analysis is similar, systematically removing one study at a time to determine its influence on the overall results. Subgroup analysis helps explore whether the effect size differs across various subgroups, while meta-regression examines the relationship between study characteristics (e.g., sample size, study quality, intervention type) and the effect size. These additional analyses can help strengthen your conclusions and reduce the risk of publication bias affecting your meta-analysis results.
Hope this may helps
  • asked a question related to Meta-Analysis
Question
1 answer
Hi all,
I have a very simple question.
When conducting a meta-analysis I encountered an individual patient data (IPD) meta-analysis and I was wondering if I can pool these outcome measures (odds ratios for instance) with the others from the single studies.
Cheers!
TBJ
Relevant answer
Answer
I don't think this approach makes sense. You may need to conduct a meta-analysis of individual patient data separately from the meta-analysis of the studies. An alternative approach could be to collect all individual patient data from one study to calculate a single effect size (e.g., one odds ratio), and then treat it as a single study in the overall meta-analysis.
  • asked a question related to Meta-Analysis
Question
4 answers
What is the difference between a systematic review and a meta-analysis?
Relevant answer
Answer
Anees A. Alyafei , Thank you for your detailed answer. Now I am clear. Thanks again.
  • asked a question related to Meta-Analysis
Question
4 answers
It is generally accepted to take the average effect size (e.g., correlation coefficient) if a study reports more than one effect size in meta-analysis. Can I apply the same rule for time-to-event data, where the log hazard ratio and its variance are of interest? Can I take the average of the variances of the effect sizes and use that value as the variance of the averaged effect size?
Relevant answer
Answer
@ Tulparay Hayirli ,
Simple average of the variances obtained from different studies will not yield the appropriate value of the variable under study.
Calculate the variance of the combined observations of the studies. Formula for calculating variance of the combined observations is available in standard book on descriptive statistics.
  • asked a question related to Meta-Analysis
Question
9 answers
Dear colleagues,
We are conducting a systematic review and meta-analysis of cross-sectional data, and I am looking for a suitable workflow management software. Those that I have worked with (RevMan) or explored (Covidence) seem to be focusing on intervention studies that do require a comparator group. We don't have this in prevalence data. Does anyone know of a software that can do the job? If open source, even better. Note that I am not looking for data analysis packages, data analysis will be done in R. What I am looking for is a program to upload the references from the search results for title screening, abstract screening, full text screening and eventually, data extraction. Thereafter, we will export to R.
Thank you in advance for your help, best, Fabian
Relevant answer
Answer
I think maybeVOSviewer?
  • asked a question related to Meta-Analysis
Question
2 answers
Hi, I am doing a meta-analysis and I need the values to be Mean (SD). A study has the mean change between two groups as GMR and CI values. Is it possible to change these values to Mean (SD) please?
Thank you for your time.
Relevant answer
Answer
Heba Ramadan thank you very much and I do agree with you.
  • asked a question related to Meta-Analysis
Question
4 answers
Can a meta-analysis be a PhD thesis topic?
Relevant answer
Answer
If you are looking at ways to improve the meta-analysis methodology and adress the existing gaps and shortcomings of meta-analysis, it can in itself be a thesis topic contributing to the improvement of research methods in scientific inquiry.
  • asked a question related to Meta-Analysis
Question
4 answers
Hello,
I am conducting a meta-analysis of mortality rates among ICU patients. I have extracted events and sample size from included studies to estimate the overall effect. I want to calculate odds ratio and 95% confidence intervals using the Mantel-Haenszel method.
I am seeking advice on the most appropriate meta-analysis model to use in this instance. Should I use the fixed-effect or random-effects model?
Thanks in advance.
Best regards,
Beatriz
Relevant answer
Answer
If you are deciding between the fixed-effect and random-effects models in your meta-analysis, then the choice depends on how different the included studies are from each other.
Fixed-effect model: In this model, we assume that all of the studies are trying to estimate exactly the same effect, and whatever differences exist between your results from study A to study Z are because of chance or random variation. It is applicable when heterogeneity is low (i.e., the studies are very similar in patient characteristics, interventions and outcomes).
Random-effects model: In this model we assume that 'the true effect size varies between studies due to real differences' (i.e, clinical diversity, variations in study design, or populations). It is generally used when heterogeneity is moderate to high among the studies.
When to choose: If the studies included in your meta-analysis are extremely homogeneous, with similar populations and interventions, the fixed-effect model may be appropriate.
If there are signs of heterogeneity (you can see this statistically using, for example, the I² statistic or Cochran's Q test), then it is usually more appropriate to use the random-effects model because it considers variability between studies.
Since ICU mortality rates can vary widely according to factors such as patient characteristics and healthcare settings, the random-effects model often recommended unless heterogeneity is minimal in such cases.
I hope this help you.
  • asked a question related to Meta-Analysis
Question
3 answers
I believe Systemic Reviews and Meta Analysis require a lot of Clinical Acumen and Expertise apart from Content Writing and Data Analysis that only Subject Specialists have.
Since Meta and Systemic Reviews are considered a high quality of evidence and can affect Clinical Practices therefore, only Subject Specialists should have the mandate for it.
it's open to discussion. Do share your insight.
#MetaAnalysis #SystemicReviews #Research #QuestionOfTheDay
Relevant answer
Answer
Yes, medical students can certainly gain valuable knowledge by writing systematic reviews and meta-analyses early in their careers. These projects help develop critical thinking, familiarize students with evidence-based medicine, and contribute to the medical literature. However, it is highly recommended that students have some form of mentorship while doing so.
  • asked a question related to Meta-Analysis
Question
2 answers
Hello everyone, I am currently working on my first meta-analysis using revman. I would really appreciate any advice on how to proceed.
For some of my articles, I have the raw data (e.g out of 12 exposed, 6 has outcome. out of 12 not exposed, 6 has the outcome). For other articles, I have unadjusted and adjusted odds ratio without any raw data.
I would like to ask 3 questions.
1. is it possible for me to combine both the raw data and unadjusted odds ratio using the generic inverse variance function to generate a forest plot?
2. can i combine unadjusted odds ratio, adjusted odds ratio and raw data in generic inverse variance?
3. is it okay if i only use the manual dichotomous function to put in raw data and leave out the studies without raw data?
Thank you very much
Relevant answer
Answer
thank you very much!
  • asked a question related to Meta-Analysis
Question
2 answers
Studies should be selected based on predefined inclusion criteria, such as study design (e.g., randomized controlled trials), population (school-aged children), and intervention type (oral health education, fluoride programs).
Sánchez-Martín, M., Gutiérrez-Sánchez, M., Olmedo-Moreno, E.M. and Navarro-Mateu, F., 2024. A systematic review to evaluate the risk of bias of meta-analyses reporting experimental educational interventions focused on academic performance. Cogent Education, 11(1), p.2385785.
Relevant answer
Answer
Hello, I would agree that predefined inclusion criteria and literature search limits (such as date and English-language) should be defined for a systematic review. Then comes a decision as to whether meta-analysis is possible and if so, which studies should be statistically combined. How similar study populations are clinically and the statistical heterogeniety are drivers to these decisions. One thing that needs more discussion in the community is our current measurement of statistical heterogeneity. According to Michael Borenstein, current measures of heterogeneity, such as I-squared were never actually designed for that purpose. He and others propose the use of the 'prediction interval' for measuring statistical heterogeneity. See Borenstein et al (2021) Introdution to meta-analysis, second edition, Wiley, Chichester.
  • asked a question related to Meta-Analysis
Question
3 answers
1. Scopus = Embase?
2. Scopus = Web of Science?
3. Scopus = Embase+Web of Science?
or
1. Scopus ≠ Embase?
2. Scopus ≠ Web of Science?
3. Scopus ≠ Embase+Web of Science?
If researchers use both Embase and Web of Science but do not include Scopus, how does this choice affect their search results?
Relevant answer
Answer
  1. Scopus = Embase?No, they are not equal. While both databases index biomedical literature, Embase has a stronger focus on European and international biomedical journals, especially those related to pharmacology and drug research. Scopus, on the other hand, covers a broader range of disciplines, including social sciences and humanities.
  2. Scopus = Web of Science?No, they are not equal. Scopus and Web of Science are similar in that they both cover a wide array of scientific disciplines and provide citation metrics. However, they differ in their indexing practices, scope, and the journals they include. Web of Science tends to focus more on high-impact journals, while Scopus offers broader coverage.
  3. Scopus = Embase + Web of Science?No, this is also not accurate. While Scopus, Embase, and Web of Science have overlapping content, each database has unique journals and articles. They each have their strengths in different areas, making them complementary rather than interchangeable.
Implications of Using Embase and Web of Science Without Scopus
If researchers choose to rely solely on Embase and Web of Science and exclude Scopus from their literature search:
  • Potential Gaps in Literature: They may miss relevant articles indexed in Scopus, particularly those from journals that are not included in the other two databases. Scopus has a broader selection of interdisciplinary journals that could contain valuable information.
  • Citation Metrics: Researchers using only Embase and Web of Science might not have access to certain citation metrics available in Scopus, which can provide insights into the impact and relevance of specific research.
  • Diversity of Sources: Excluding Scopus might limit the diversity of the literature reviewed, potentially skewing the results or conclusions drawn from the research.
  • asked a question related to Meta-Analysis
Question
12 answers
A meta analysis has been done considering the articles published between the year 1997 and 2004. I am interested to do meta analysis in the same topic. Is it valid?. can I take all articles without time restrictions or is it better to take articles after 2004?
Relevant answer
Answer
You can revise if there is some clue that your new review will add something new to the field.
The previous review might have issue in conduct like lack of proper search in enough databases, non focused research question, not reporting negative outcomes, inadequate statistics , new good quality studies publication etc
  • asked a question related to Meta-Analysis
Question
5 answers
Hello everyone,
My greetings to all the scholar.
Recently, I am conducting a systematic review and meta-analysis, that will evaluate the psychological factors affecting a certain behavior (for example impulsivity). Initial sorting found most of the papers estimated the effect size by structural equation modelling. There is a path analysis also found in several studies. For example, one paper showed the anxiety causes the impulsivity. The fact is, the whole thing was hypothesized first, then analyzed by structural equation model. In the model, the anxiety was mediated by some other factor and caused impulsivity. For example, please see the attached file.
Now, I need to extract the data from these types of papers where most of the cases were mediated or have direct and indirect effect on the dependent variable. To conduct a meta-analysis how can extract the data and information from these?
It would be very helpful if there is any detailed methods, example, references and guidelines on this problem.
Relevant answer
Answer
To extract data from structural equation models (SEMs) for conducting a meta-analysis, follow these steps:
  1. Identify Key Parameters: Focus on parameters like effect sizes (e.g., path coefficients), standard errors, and confidence intervals from the SEM results.
  2. Collect Data: Gather relevant SEM outputs from multiple studies, ensuring consistency in the variables and models used.
  3. Calculate Effect Sizes: If effect sizes are not directly provided, calculate them from available statistics (e.g., converting path coefficients into correlation coefficients).
  4. Standardize Data: Ensure that the effect sizes are in a comparable format, adjusting for differences in scales or measurement.
  5. Use Meta-Analytic Software: Input the extracted data into software like Comprehensive Meta-Analysis (CMA) or R packages (e.g., metafor) for analysis.
By following these steps, you can systematically extract and analyze data from SEMs for your meta-analysis.
  • asked a question related to Meta-Analysis
Question
11 answers
Hi colleagues,
I hope you’re doing well. I am currently conducting a meta-analysis on the interaction effect between A and B, and I need some guidance on 1) which effect size to extract from the primary studies, and 2) how to convert other types of effect sizes to the chosen one.
I’ve noticed that most existing meta-analyses and guidelines (e.g., Hunter & Schmidt, 2004), focus primarily on correlational or treatment effects. The literature on moderator analysis (e.g., the moderating effect of study characteristics on the focal relationship) does not seem directly applicable to my study.
Any help or recommendations for specific references or literature would be greatly appreciated!
Thank you in advance for your kind help.
Relevant answer
Answer
Your attachment 2 demonstrates the difficulty (perhaps, impossibility) of comparing the A*B interaction across studies when the other variables in the models are not identical.
Apparently, including C1 in the model introduces a multicollinearity problem. In step 1, the additive effects are all non-significant, despite an adjusted R-sq of .24 (which, with n=250, indicates the additive model as a whole must be significant). Similarly in step 2, the 3 interactions are all non-significant, despite a significant increment to R-sq for the 2-way interactions as a block. Those are typically symptoms of multicollinearity, which renders any attempt to interpret the individual coefficients highly suspect.
The model with C2 controlled, instead, is also peculiar. On step 2, each of the 3 interaction terms is significant, but the block of 2-way interactions does not add significantly to R-sq. It's not obvious how that could be. Also, standardized slopes of greater than 1.0 are rarely found, but here most of them are. From the looks of things, C2 may be a suppressor variable; failing to control for C2 (in step 1 of the model with C1 instead) suppresses the additive effects of both A and B so much they look weakly negative instead of strongly positive.
My point is, unless the models include the same control variables, neither the additive effects of A and B nor the interaction of A with B can be compared conclusively. The fact that A and B are coded differently across studies (sometimes categorically, sometimes continuously) makes matters worse.
So, it seems to me that in your meta-analysis you need to separate the studies into those where you can make a straight-up, apples to apples comparison and those where you cannot do so. In the former group, you could use the slope of the A-B interaction (preferably unstandardized slope, since even if A and B are measured identically across studies they might have different variances in different studies), and/or the change in R-sq. For the studies that are not perfectly comparable, it might be the best you could do would be to categorize the effect size for the A-B interaction very roughly into Little or No Effect, Medium Effect, Strong Effect. For example, if R-sq change is substantial for step 2, and the AB term is significant while the AC and BC terms are not, it's reasonable to attribute (most of) the R-sq change to the AB interaction.
  • asked a question related to Meta-Analysis
Question
1 answer
Hello Researchers,
We are attempting a meta-analysis of studies regarding relationships between Sensory Processing Sensitivity (SPS) measured with the Highly Sensitive Person Scale (HSPS) and Big Five personality traits. We would like to ask you to provide your unpublished results of such correlations.
Data needed:
Authors, Year, if you used the original HSPS or modified it, modifications to the scale (if applicable), what subscales you used (if applicable), Personality scale used, sample size, country, mean age, sample characteristics, correlation HSPS-Openness, HSPS-Consciousness, HSPS-Extraversion, HSPS-Agreeableness, HSPS-Neuroticism, correlations between personality dimensions and HSPS subscales (if Smolewska et al. (2006) scales were used - EOE, LST, AES), Cronbach's Alfa for HSPS and subscales.
If your data is not analyzed, we would welcome the raw dataset.
Our meta-analysis is preregistered here: https://osf.io/n2wj5
Relevant answer
Answer
Dzień dobry,
tak, mamy większe badania młodzieży i dorosłych z wykorzystaniem m.in. IPIP-BFM-20, większość niepublikowana; proszę o maila: monika.baryla@wsei.lublin.pl
Pozdrawiam,
Monika Baryła-Matejczuk
  • asked a question related to Meta-Analysis
Question
3 answers
Dear researchers,
In a systematic review (not a meta-analysis) compiling studies on various diagnostic systems against a specific pathogen. The most relevant parameters evaluated are the type of material used, the type of sample used, and the detection limit achieved.
It is important to note that these are not clinical or observational studies, and no diagnostic performance parameters are being compared to a gold standard.
What type of application or platform would be most suitable for evaluating the quality (risk of bias) of the selected articles? Would it be possible to modify any published platform?
Thank you in advance for your assistance.
Sincerely,
Daniel
Relevant answer
Answer
Possible Modifications:
  1. Domain 1: Patient Selection (or "Sample Selection" in your case):Focus on whether the selection of samples was appropriate for the type of pathogen being tested, considering biases in sample type (e.g., environmental, biological) rather than patient populations.
  2. Domain 2: Index Test (Diagnostic Systems in your case):Assess the methodology of the diagnostic systems in terms of consistency, reproducibility, and any reported limitations in the materials and detection limits.
  3. Domain 3: Reference Standard:Since no gold standard is used, this domain can be excluded or simplified. You may instead assess how well the studies justify their chosen detection limits and materials.
  4. Domain 4: Flow and Timing: Adapt this domain to focus on the reproducibility of experiments and whether the studies adequately describe the processes and conditions under which the tests were performed. Regards
  • asked a question related to Meta-Analysis
Question
3 answers
Hi!
I was studying diagnostic meta-analysis by Jones et al (
and I tried to calculate the Q value from cited.
"Q is the intercept of the SROC and the antidiagonal line through the unit square. Its value indicates overall accuracy by finding where sensitivity and specificity are the same"
1. I started inserting the confuse matrix data and making a reitsma object from "mada" package
2. Then I gave it's value to the sroc() function with the return_function method set it to T in order to give me the generic function of sROC (let's call it f(x))
3. I then used uniroot() to find the (1-specificity) value where sROC and the anti-diagonal curve intercepts each other.
4. Finally, I gave the false positive rate back to f(x) and found the sensitivity, and so, the Q value.
Is there a more direct approach for this in R?
Relevant answer
Answer
I think the Q value if looking for the paper you sent is just the point you'll get from the meta-analysis, which is the pooled accuracy throughout possible thresholds of the test ?
I'm not sure I've catched the question correctly.
Maybe if you have many studies for different thresholds you could run several meta-analyses (1 for each threshold) and then deciding which is the optimal (first not differentiating costs of false negative and false negative (ie Se and S have the same value) as well as in a 2nd step incorporating misclassification cost term (using the ratio of cost btw FN and FP as well as several realistic prevalence scenari)).
  • asked a question related to Meta-Analysis
Question
1 answer
Hi all, I am wondering if anybody knows how to calculate the effect size (e.g. Cohen's d) based on the information provided in this table (see image) comparing each intervention condition to the control group. At the bottom, it provides the mean and standard deviation for each outcome for the control group. Rather than providing the mean and standard deviation for the intervention groups, it presents an estimated treatment effect. The article states "The treatment effects may be interpreted as average outcome differences between those from treatment groups and those from the control group...." So if positive, you'd add the estimated treatmenty effect to the control group mean to get the estimated mean for the treatment group. It also provides the standard error of the estimated treatment effect in brackets (but I believe this is not the same as the SE of the treatment mean - but maybe it is possible to calculate or estimate that?). So you have a mean and SD for the control group but only and estimated mean for the treatment group, if I'm understanding correctly. Any recommendations and insights would be helpful.
Relevant answer
Answer
Matthew Hagler The following paper may be of some help to get a little guidance. Groß J and Möller A (2023) A Note on Cohen’s d From a Partitioned Linear Regression Model, Journal of Statistical Theory and Practice, 17:22 https://doi.org/10.1007/s42519-023-00323-w
  • asked a question related to Meta-Analysis
Question
3 answers
I am at the end of conducting a large systematic review and meta-analysis. I have experience of meta-analysis and have attempted to meta-analyse the studies myself, but I am not happy with my method. The problem is that almost all the studies are crossover studies and I am not sure how to analyse them correctly. I have consulted the Cochrane Handbook, and it seems to suggest a paired analysis is best, but I do not have the expertise to do this - https://training.cochrane.org/handbook/current/chapter-23#section-23-2-6
I am seeking a statistician familiar with meta-analysis to consult with, and if possible, undertake the meta-analysis. There are only two authors on this paper (me and a colleague), so you would either be second or last author. We aim to publish in a Q1 or Q2 journal, and from my own analysis I can see we have very interesting results.
Please let me know if you are interested.
Relevant answer
Answer
Depending on the structure of the data (how much pre-processing has been already done), I would be ready to conduct the meta-analysis as well. Please feel free to reach out by PM.
  • asked a question related to Meta-Analysis
Question
1 answer
Any recommendations ?
Relevant answer
Answer
Seif Hundam PubMed offers filters to specifically extract systematic reviews of animal trials. If you're unable to find relevant articles, let me know, and I'll search other biomedical databases if you have limited access.
  • asked a question related to Meta-Analysis
Question
3 answers
A paper has been Retracted by the author for population problem what about meta-analysis with this
Relevant answer
Answer
i think , letter to the editor will help you
  • asked a question related to Meta-Analysis
Question
1 answer
Relevant answer
Answer
Reliability Generalization Meta-Analysis of GHQ-12
  • asked a question related to Meta-Analysis
Question
1 answer
I am excited to announce an opportunity for dedicated researchers to join our dynamic team for an ongoing meta-analysis study. If you are passionate about research and have a keen interest in organizational behavior or management area (e.g., leadership, innovative behaviours, employee eattitudes, perceptions etc.), we would love to hear from you!
Project Overview:
Title: Meta-Analysis on Leadership styles and various theoretical correlatesç
Objective: To synthesize existing research findings and provide comprehensive insights into how and whic leadership styles are more effective in spesific outcomes.
Scope: Our study aims to cover various aspects of leadership stles including but not limited to:
  • Behaviours
  • Perceptions
  • Attitudes
  • Emotions
  • Orientations
What We Are Looking For:
Position: Researcher / Co-author
Qualifications:
  • Ph.D. degree in Management
  • Strong background in research methodology and statistical analysis
  • Experience with meta-analysis techniques is highly desirable
  • Proficiency in data analysis software (e.g., SPSS, R, Stata)
  • Excellent analytical and critical thinking skills
  • Strong written and verbal communication skills
  • Ability to work collaboratively in a team environment
Responsibilities:
  • Conduct literature reviews and data extraction
  • Perform statistical analyses and data synthesis
  • Contribute to the interpretation and presentation of findings
  • Assist in manuscript preparation for publication
  • Participate in regular team meetings and discussions
Benefits:
  • Opportunity to contribute to impactful research
  • Collaborative and supportive team environment
  • Potential for co-authorship on research publications
  • Gain valuable experience in meta-analysis and advanced research methods
How to Apply:
Interested candidates are invited to submit the following documents:
  • A cover letter outlining your interest and relevant experience
  • Curriculum Vitae (CV)
  • A sample of previous research work (if available)
Deadline for Applications: 16.08.2024
Submit Applications To: borayildiz@istanbul.edu.tr
Mail Subject: Research Team Application for Meta-Analysis Project
For more information or any inquiries, please contact Bora Yildiz at borayildiz@istanul.edu.tr
Join us in advancing knowledge and making a meaningful impact in management field. We look forward to welcoming enthusiastic researchers to our team!
Relevant answer
Answer
Yet, it is my pleasure to joint with your team to enrich your research
  • asked a question related to Meta-Analysis
Question
2 answers
Hi, community!
I am conducting a meta-analysis and meta-regression to calculate the pooled adjusted odds ratio (AOR) and I² with the p-value for variables associated with hypertension prevalence. I have a dataset with the following columns:
  • study_id: Study identifier
  • AOR: Adjusted odds ratio (each independent variable)
  • lower_CI: Lower confidence interval (each independent variable)
  • upper_CI: Upper confidence interval (each independent variable)
  • variable: Independent variable
Here is the script I am using in R:
# Calculate the standard error (seTE)
data$seTE <- (log(data$upper_CI) - log(data$lower_CI)) / (2 * 1.96)
# Meta-analysis
meta_analysis <- metagen(TE = log(data$AOR),
seTE = data$seTE,
data = data,
studlab = data$study_id,
comb.fixed = TRUE,
comb.random = TRUE)
I would like to know if this script is correct for achieving my goals of:
  • Calculating the pooled AOR and the 95% confidence interval.
  • Calculating the I² and the p-value to assess heterogeneity.
Any feedback or suggestions for improvement would be greatly appreciated!
Thank you!
Relevant answer
Answer
  • asked a question related to Meta-Analysis
Question
5 answers
Hello everyone,
I have written a narrative review on a topic obtaining the literature from other research articles and review papers. But I wish to convert it to systematic review (without meta analysis) now. I have noticed that most systematic reviews are based on clinical trials. Is it still possible to get it done based on my sources?
Relevant answer
Answer
It is not possible to convert a narrative review into a systematic review because a systematic review will require a detailed step-by-step review protocol which outlines the following:
[1]what is the review question?
[2]where to search and how to search?
[3]strict eligibility criteria to ensure that only eligible studies will be included in the review
[4]how to perform data synthesis (i.e. either by meta-analysis or by narrative synthesis).
Furthermore, a systematic review involves collating evidence by using all of the eligible and critically appraised literature available on a certain clearly-defined topic. A narrative review, on the other hand, merely aims at identifying and summarizing what has previously been published on a broader scope of the subject.
Therefore, the major difference between a narrative review and a systematic review is that the main purpose of a narrative review is to deepen the understanding in a certain research area. This is in contrast to the results of a systematic review, which can provide the most valid evidence to guide clinical decision-making and inform policy development. Therefore, some of the high-quality systematic reviews have now become the gold standard in evidence-based medicine.
Although a majority of systematic reviews are based on interventional clinical trials, it is still possible for a systematic review to be based on observational studies such as cross-sectional studies, etc..
In fact, some of the systematic reviews are actually including meta-analysis of observational studies.
Since you already have written up a narrative review, therefore you should use it as a basis to formulate the overall rationale for preparing a systematic review protocol and then register it in PROSPERO, if you have found that no such reviews have already been written up by other authors.
This is because some of the information in the narrative review can be very useful for providing a supporting framework of a systematic review protocol.
However, in order to write up a systematic review protocol, it is first necessary to gather a team of like-minded authors, who are committed towards the writing up of both the systematic review protocol as well as the full systematic review (incorporating all the review findings).
Once you have formed a team of like-minded authors, then all the authors can either decide to register this new systematic review protocol in PROSPERO, if no such protocols and/or reviews have ever been written up by other authors before.
  • asked a question related to Meta-Analysis
Question
4 answers
This is for a meta-analysis using generic inverse variance method and random-effects model in RevMan. The exposure is smoking and outcome is mortality due to TB.
Relevant answer
Answer
Combining Hazard Ratios (HRs) with Odds Ratios (ORs) or Risk Ratios (RRs) in a meta-analysis can be challenging and is generally not recommended without careful consideration. Here is a detailed explanation:
Interpretation Differences :Hazard Ratios (HRs) measure the rate at which an event occurs over time, which is particularly relevant for survival analysis. Odds Ratios (ORs) compare the odds of an event occurring in one group to the odds of it occurring in another group. Risk Ratios (RRs) (also known as relative risks) compare the probability of an event occurring in one group to the probability of it occurring in another group. Hence, you need to choose one best measure based on your data and outcomes
  • asked a question related to Meta-Analysis
Question
5 answers
Hi everybody,
We are trying to write a systematic review meta-analysis paper. But I could find 19 references. I think 19 references are not enough to do a meta-analysis section and it is better to just write a systematic review. What do you think?
In addition, about 4 of them are non-English (Farsi) references. Can we use them? Or Can we use reference paper?
Maryam
Relevant answer
Answer
Check heterogeneity, quality, and publication bias. And if the results are acceptable, you can conduct meta-analysis for 19 studies. Meta-analyses often aim for at least 10-20 studies to ensure a sufficient sample size for meaningful statistical analysis and to provide a comprehensive synthesis of the evidence.
You can include non-English references, such as Farsi papers but consider your
Cabilability to understand and interpret the results of these studies. If language barriers prevent thorough evaluation or synthesis of these studies, you should ignore them.
  • asked a question related to Meta-Analysis
Question
2 answers
What are the potential reasons that most studies fall outside the 95% confidence interval?
Relevant answer
Answer
It looks like this plot is incorrect. The contours should match the pooled effect estimate, meaning the red line should be in the middle of the dark grey triangle (i.e. the dark grey triangle needs to move over to the right a bit).
  • asked a question related to Meta-Analysis
Question
4 answers
Dear all,
We have submitted a manuscript for publication that presents a systematic review and meta-analysis evaluating the influence of a gene polymorphism on cancer risk. The study involved the selection of published case-control studies from various countries across all continents, comparing the allele frequencies of a specific gene polymorphism in populations with cancer to those of healthy subjects.
The reviewer has requested "External validity is missing, please provide."
However, I am unfamiliar with what constitutes external validity in this context.
Relevant answer
Answer
You can refer to the following sources of information should you require any further clarifications and/or explanations on external validity of a meta-analysis.
  • asked a question related to Meta-Analysis
Question
2 answers
It is well known in current scenario, the importance of systematic reviews and meta-analyses, as I could see a lot questions related to it, would a skilled supportive community can play a crucial role in enriching the society with quality reviews and meta analysis with 24*7 support system.
If so, how many would
1. Recommend,
2. Highly recommend
3. Not necessarily required
How many of you would be interested being a part of support community? and what would be your role?
Relevant answer
Answer
In many respects, the Cochrane Collaboration (medicine, health) and Cambell Collaboration (social science) already serve this function
  • asked a question related to Meta-Analysis
Question
2 answers
Dear researchers. I have extracted data from graphs for meta analysis. I am stuck to find the SD for the obtained data. Anyone who can help me to sort out this problem with formula?
Thank you
Regards
Mukesh Kumar
Relevant answer
Answer
First of all, you should make sure that the information you need (mean and standard deviation) is reported in the graph with the type you want. Many clinical articles report CI instead of SD with the mean in the graphs. You have to read the graph's information to be sure.
If the SD was reported in the graph, you can see it as a bar above and below the mean value. Take a picture of that part of the article, then enter the digitizer software or website. There, specify the exact parts of the graph and determine the values.
  • asked a question related to Meta-Analysis
Question
3 answers
Hello everyone,
I am conducting a meta-analysis to find if x has superior effect than y on the outcome. I used the SMD method and I got a significant moderate heterogeneity of a value I2: 52%
should I do the subgroup analysis to find out where the heterogneity came from?
I have only 16 studies and if i want to subgroup by intervention types (EG), I dont have an equal number of studies for each group. also when I wanted to subgroup by health status, I had 6 studies that used persons with MS, 1 study that used persons with stroke, 1 study used healthy population, 3 studies with MCI etc... so the number of studies is not equal among the subgroups. can I still do that?
Relevant answer
Answer
A similar question to yours has been posted to ResearchGate & answered in 2021.
In summary, there is no unanimous consensus on the minimum number required for subgrouping. It would help if you tried addressing the heterogeneity by using a random effects model (instead of a fixed effects model) and using a leave-one-out test.
If those two failed, try your luck with a subgroup analysis.
  • asked a question related to Meta-Analysis
Question
3 answers
I want to run a meta-analysis for linkage mapping and GWAS QTLs and I will require a software to be able to achieve this.
Relevant answer
Answer
Where to find this package. it is not available in cran
  • asked a question related to Meta-Analysis
Question
4 answers
My study aims to synthesise data on the mean age of participants when they were diagnosed with hearing loss, and I wanted to conduct a meta-analysis to obtain the meta-analysed mean age of identification with SD... I have obtained data from 12 studies that met the inclusion criteria and am now stuck at how to compute meta-analysis.
Relevant answer
Answer
  • asked a question related to Meta-Analysis
Question
4 answers
I am creating a forest plot for a meta-analysis and require assistance in adding a superscript after the Author/Year on the left side of the graph. Any help would be greatly appreciated.
Relevant answer
Answer
You can simply start the graph editor and change the textbox properties by double-clicking on the corresponding study. As an alternative, you can also add superscript by changing the label of the corresponding study identifier using "replace" and update the meta settings ("meta update"). The study identifier of the Forest plot ("meta forestplot") should then also adopt the changed label.
  • asked a question related to Meta-Analysis
Question
1 answer
I had a valid idea for a meta-analysis involving multiple prospective & retrospective studies with no prior meta-analyses on the same chosen sub-population.
When confirming the validity of my idea on PROSPERO, I found out that another team registered a protocol involving the same exact idea in late 2021 (with the most recent update in early 2022).
So far, this team has produced no research output.
I got in touch with the correspondent on PROSPERO via e-mail to enquire about any recent updates but got no reply.
How could one approach such a scenario? I fear that while working on the meta-analysis, the other team may publish their study (with the same idea), which would result in the duplication of evidence.
Thank you beforehand.
Relevant answer
Answer
Many similar meta-analyses are published within a short time frame (e.g., several months or one year), but I understand your concerns. If the new meta-analysis is largely redundant, it could be interpreted as a waste of resources. However, if, after reading the PROSPERO protocol, you have the impression that you don't agree with some critical decisions and would change some aspects (e.g., include more databases, optimize search strings, broaden the scope of the review), then it might be worth doing your own meta-analysis.
  • asked a question related to Meta-Analysis
Question
1 answer
Hi,
I am currently creating a meta-analysis on the effect of growth performance of pigs in response to dietary fiber content in experimental diets as well as the influence of a fiber enzyme supplement.
I am having trouble entering data collected from research articles and was hoping for some clarification.
Example article (Koo et al., 2017) - study used a 3x 2 factorial design where authors looked at 3 diets (diet A (complex 1), B (complex 2), C (simple)) and 2 levels of multicarbohydrase supplementation (0% or (-) and 1% (+)). The authors then reported the growth performance results as ADG, ADFI and G:F (picture posted here). In this case, I am just collecting the day 1 to 28 reported data. As you can see, the authors report growth performance points for 5 variables (Diet A,B,C and (-) and (+) multicarbohydrase levels)
In terms of dietary content, the authors just report the dietary content of each diet (A,B,C)
When I enter this collected data, I need to report the growth performance results in addition to the dietary content of the experimental diet used for that growth performance endpoint. For example, how do I know what experimental diet content is in the Multicarbohydrase (+) and (-) endpoints?
Since this is a 3 x 2 factorial design I was thinking there would be 6 treatments (Each diet with each enzyme level) but there are only 5 so how do I know which treatment has which dietary content?
Here is the paper I am referencing as well. -
Relevant answer
Answer
It took me a while to understand this. In my opinion, the data representation here is quite poor. Measurements taken during different periods add to the confusion, as they appear to be another factor. However, this might be a standard method of presenting such data in animal husbandry.
The data presented in the table do not represent results obtained from specific combinations of factors. Instead, they show the summary main effects for each factor (check picture). As a result, we have five "results." Since one level of the supplement is 0%, the authors could actually calculate the impact of MC on the diet from the main effects and interactions.
  • asked a question related to Meta-Analysis
Question
1 answer
For example, some forest graphs include both total and subtotal results.
Relevant answer
Answer
Subtotal results may refer to the combined effect size estimate within a specific subgroup of studies.
  • asked a question related to Meta-Analysis
Question
2 answers
What methods are recommended for synthesizing outcomes
from multiple studies, and why is meta-analysis often
preferred?
Relevant answer
  • asked a question related to Meta-Analysis
Question
1 answer
The topic can cover any area of this specialty.
Relevant answer
Answer
Greetings Qamar,
Thank you for your question.
General Surgery is a broad specialty with a plethora of sub-specialties and sub-subspecialties underneath it.
To find a valid meta-analysis idea, I would personally advise you to narrow down your scope to a subspecialty of your interest. Try subscribing to journals & updates falling under this particular specialty and read - as frequently as possible - the most recent publications. Additionally, you may use websites such as "Medscape" to remain up-to-date with the latest advancements in your specialty of choice. This approach may help you identify possible gaps in literature which may be addressed appropriately by conducting a meta-analysis.
When validating your meta-analytic idea, try making sure it follows the FINER criteria [Although ethics might be overlooked when conducting secondary research as the primary studies you're trying to pool have already had their ethical approval].
Hopefully this answers your question!
Best Regards,
Mohamed Ibrahim
  • asked a question related to Meta-Analysis
Question
4 answers
Hi all!
I have a question & any help would be appreciated (especially Dr. Holger Steinmetz & Dr. Jan Antfolk).
Suppose we are conducting a Meta-analysis & looking at 2 Dichotomous outcomes. Outcome 1 is reported in 14 studies (all observational, no RCT) with different measures (OR= 5/14, RR= 2/14, PR= 2/14, % Raw data=5/14). Outcome 2 is reported in 3 studies (OR=1/3, HR=1/3, Raw data=1/3).
Which Effect size to use for each outcome & how to convert one into another?
Relevant answer
Answer
I agree with Heba Ramadan, choose either RR, OR or Hazard ratio (HR), depending on what makes most sense and what is more applicable for your research question and commonly reported measures in that field. For some cases, OR or Hazard ratio may be more applicable, while RR is much more intuitive to interpret.
Check out this material for more info:
  • asked a question related to Meta-Analysis
Question
2 answers
Hi everyone, for some years now I've been interested in doing meta-analysis in my field of study. I am a botanist, who recently worked in seed biology. during my self-learning, I already knew how to do systematic reviews, but stuck there while I wanted to improve myself in meta-analysis.
Thus, I write to express my desire to reach everyone who may have experience in this topic and is willing to let me learn from their experience. thanks.
Relevant answer
Answer
  • asked a question related to Meta-Analysis
Question
4 answers
Hello everyone, Is it possible to get your recommendations on which meta-anlysis program I should be learning? R vs Revman vs CMA vs Stata
Relevant answer
Answer
If you are a beginner, I would suggest first starting with Revman or CMA. After that you can build up to R or STATA. The features you'll learn in Revman or CMA helps in understanding the different components of running analysis on R or STATA
  • asked a question related to Meta-Analysis
Question
4 answers
Hello everyone, Is it possible to get your recommendations regarding which meta analysis program i should be using? R vs Revman vs CMA or SPATA?
Relevant answer
Answer
Choosing the right program for meta-analysis depends on various factors such as your familiarity with statistical software, the complexity of your analysis, and your specific needs. Here's a brief overview of the options you mentioned:
1. **R**: R is a powerful statistical computing language that offers numerous packages for conducting meta-analysis. It provides flexibility and customization options but may have a steeper learning curve for beginners.
2. **Revman (Review Manager)**: Revman is a software developed by the Cochrane Collaboration specifically for conducting systematic reviews and meta-analyses. It's user-friendly and widely used in the field of healthcare research.
3. **Comprehensive Meta-Analysis (CMA)**: CMA is a user-friendly software designed specifically for meta-analysis. It offers a range of statistical techniques and visualization tools tailored for meta-analytic research.
4. **SPATA (Spatial and Temporal Analysis)**: SPATA seems to be less commonly known compared to the other options you mentioned. Without more information, it's difficult to provide specific insights into its suitability for meta-analysis.
Consider factors like your level of expertise, the features you require, and compatibility with your research context when making your decision. Additionally, exploring tutorials or seeking advice from colleagues who have experience with these programs can help you make an informed choice.
  • asked a question related to Meta-Analysis
Question
1 answer
Is it possible to conduct a meta-analysis for a single group in the REVMAN program? If so, could you please provide guidance on where to find instructions for conducting this type of meta-analysis?"
Relevant answer
Answer
Yes, it's possible to conduct a meta-analysis for a single group in the RevMan program. This type of meta-analysis is often referred to as a "single-arm meta-analysis" or "one-sample meta-analysis." In RevMan, you can perform this type of analysis by treating the data from your single group as if it were the treatment group in a typical meta-analysis comparing two groups.
Here's a basic outline of how to conduct a single-arm meta-analysis in RevMan:
1. **Prepare your data**: Organize your data into the appropriate format for RevMan. This typically involves recording the outcome measure of interest (e.g., mean difference, proportion, etc.) along with measures of variance (e.g., standard deviation, standard error, confidence interval).
2. **Create a new review**: Open RevMan and create a new review project.
3. **Enter study data**: Enter the data for your single group study into RevMan. You can do this by adding a new study and entering the relevant outcome data into the appropriate fields.
4. **Specify comparison groups**: Since you only have one group, you'll need to specify a comparison group for the analysis. You can create a "dummy" comparison group with placeholder data or use data from a control group in a similar study if available.
5. **Perform analysis**: Once you've entered all your data, you can perform the meta-analysis using RevMan's analysis tools. Choose the appropriate statistical model based on the type of outcome data you have (e.g., continuous, binary, etc.).
6. **Interpret results**: Review the results of your meta-analysis, including summary effect estimates, confidence intervals, and measures of heterogeneity. Interpret the findings in the context of your research question and study limitations.
Unfortunately, RevMan's user guide does not specifically address single-arm meta-analyses. However, you can find general instructions for conducting meta-analyses in RevMan in the Cochrane Handbook for Systematic Reviews of Interventions, which provides detailed guidance on using RevMan for various types of analyses. Additionally, you may find tutorials or online resources from the Cochrane Collaboration or other research organizations that offer guidance on conducting meta-analyses in RevMan.
  • asked a question related to Meta-Analysis
Question
3 answers
I barely need this for meta-analysis in my study... but it cannot be downloaded from the server.
Relevant answer
Answer
Mohammad Al-baruni Chowdhury Revman is not currently accessible for free, but there are alternative software options for conducting meta-analyses. If you're considering other tools, I'll possibly try to assist you.
  • asked a question related to Meta-Analysis
Question
5 answers
I am working on a meta-analysis on framing with cultural-level moderators (e.g. Hofstede dimensions including Individualism-Collectivism and Power Distance) and moderators based on findings in the literature (e.g. health behavior function, behavioral frequency). While the potential mechanisms and theoretical basis of moderations would be different with different moderators, they are highly correlated (r > 0.70, or V > 0.50 for two categorical moderators). What are the possible ways to address the potential confounds between these moderators *in the context* of a meta-analysis? Let's say I find support for moderations with both Moderator A (p < .001) and Moderator B, I am not sure how to know if "significant moderation" of B is due to strong correlations/confounding relationship with A, or if both moderators are really meaningful moderators. Thank you. Would appreciate if there is (ideally R) open data/code/example.
Relevant answer
Answer
I just realized the correlations remain very strong (actually, exactly the same) after mean-centering. Then I read this post: https://stats.stackexchange.com/questions/95404/is-centering-a-valid-solution-for-multicollinearity What are the possible solutions to actually address multicolinearity in the context of *multiple-moderator* meta-regression? (Would really appreciate there is R code for me to follow/adapt)
  • asked a question related to Meta-Analysis
Question
3 answers
Dear Experts,
I have a question, I am analyzing data for meta-analysis, is this possible SMD greater than 1 for any study,
I have a study in my data indicate 2 .03 SMD.
Relevant answer
Answer
Don't know specific situation,Dare not comment,But you need to analyze from the basic concept of "SMD".
  • asked a question related to Meta-Analysis
Question
2 answers
I am wanting to perform a meta-analysis and some of the articles included only provide baseline and post-intervention mean and standard deviation values for the group. Hence, I´m wanting to calculate the mean and standard deviation of the difference between pre-intervention and post-intervention values within that group. I´ve attached an image to make the explanation easier: if I only have the information in the first 2 columns, is it possible to calculate the 3rd column?
I wonder if there is any way (in STATA or any other software) that this may be calculated.
Thank you very much in advance for your help.
Relevant answer
Thanks for sharing. My question is about the r-value. I saw that you used 0.7. How do I know which value to use in my article?
  • asked a question related to Meta-Analysis
Question
3 answers
Need advice on user-friendly tools to ease meta-analysis process of selecting eligible and fugitive studies
Relevant answer
Answer
R statistical environment (R Core Team, 2024) with several flexible packages including my favourite {metafor} package (Viechtbauer, 2010).
1. R Core Team (2024). R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. https://www.R-project.org/
2. Viechtbauer, W. (2010). Conducting meta-analyses in R with the metafor package. *Journal of Statistical Software, 36*(3), 1–48. https://doi.org/10.18637/jss.v036.i03
  • asked a question related to Meta-Analysis
Question
9 answers
Dear Colleagues,
We are currently conducting a qualitative meta-analysis and looking for qualitative research that is focused on transgender, non-binary, and gender diverse people’s experiences of gender identity development and how their gender functions to support coping with minority stress as well as increasing resilience and flourishing. We are looking specifically at articles that focus on participants in the United States. We are contacting scholars to ask if they have authored or are aware of studies that may meet our inclusion criteria, particularly any new or unpublished studies. Our team will screen the articles to determine if they meet our inclusion criteria. If you know of any studies that may be relevant to our qualitative meta-analysis, please contact or send them to Kelsey Kehoe at kelsey.kehoe001@umb.edu.
Thank you!
Heidi Levitt & Kelsey Kehoe
Relevant answer
Answer
Youth Transgender Care Policies Should Be Driven by Science
"In the U.S., some states guarantee minors full access to gender-affirming medical care while others ban such care outright. Instead, states should follow Europe’s example by adjusting policies based on weighing the emerging clinical evidence, writes independent healthcare analyst Joshua Cohen..."
Many references are given in text by hyperlinks provided.
  • asked a question related to Meta-Analysis
Question
3 answers
I'm looking for good (freely-available) resources that guide statistical approaches for conducting meta-analyses; specifically, those addressing (1) which effect size statistic to use in different situations, (2) if and when different effect size statistics (e.g., mean difference, correlation coefficient, etc.) can be combined in a meta-analysis and when they should not be combined
Thanks!
Relevant answer
Answer
For resources on statistical approaches for conducting meta-analyses, especially regarding effect size statistics and their combination, you can explore the following:
  1. The Cochrane Handbook for Systematic Reviews of Interventions: This handbook provides comprehensive guidance on conducting systematic reviews and meta-analyses, including detailed discussions on effect size statistics and their appropriate use in different situations. It covers topics like selecting effect size measures, handling different types of data, and combining effect sizes across studies.
  2. The Handbook of Research Synthesis and Meta-Analysis by Harris Cooper, Larry V. Hedges, and Jeffrey C. Valentine: This book offers in-depth discussions on various aspects of meta-analysis, including effect size measures and their interpretation. It provides guidance on selecting appropriate effect size statistics based on the research question and data characteristics, as well as considerations for combining effect sizes from different studies.
  3. and I particularly like this book, which hope will be useful ("Introduction to Meta-Analysis" by Michael Borenstein et al.)
  • asked a question related to Meta-Analysis
Question
6 answers
Hello everyone, I hope all thing is OK.i have a paper based on meta analysis, please let me know could you help me in statistical analysis of this paper? Best regards
Relevant answer
Answer
Dear professor , I would like to thank you for your answer to my researchgate question .I would like to let you know the title of our paper will be "Meta-analysis of application of particle swarm optimization in geophysical data inverse problem solving". I have collected all papers in this field with this format (about 100 papers ) in 8 categories (a,b,c,d,e,f,g,h):The main applications of PSO to the geophysical inverse problem include the interpretation of: a. vertical electrical sounding (VES) (Fernández-Álvarez et al. 2006; Fernández Martínez et al. 2010a; Pekşen et al. 2014; Cheng et al. 2015; Pace et al. 2019b); b. gravity data (Yuan et al. 2009; Pallero et al. 2015, 2017, 2021; Darisma et al. 2017; Jamasb et al. 2019; Essa and Munschy 2019; Anderson et al. 2020; Essa and Géraud 2020; Essa et al. 2021);c. magnetic data (Liu et al. 2018; Essa and Elhussein 2018, 2020); d. multi-transient electromagnetic data (Olalekan and Di 2017); e. time-domain EM data (Cheng et al. 2015, 2019; Santilano et al. 2018; Pace et al. 2019c; Li et al. 2019; Amato et al. 2021); f. MT data (Shaw and Srivastava 2007; Pace et al. 2017, 2019a, c; Godio and Santilano 2018; Santilano et al. 2018) and radio-MT data (Karcıoğlu and Gürer 2019); g. self-potential data (Santos 2010; Pekşen et al. 2011; Göktürkler and Balkaya 2012; Essa 2019, 2020) and induced polarization (Vinciguerra et al. 2019); h. Rayleigh wave dispersion curve (Song et al. 2012) and full waveform inversion (Aleardi 2019). please guide me how to arrange them for you to analyse result and calculate impact effect of papers and perform our meta analysis method? I am looking forward to hearing from you as soon as possible. Best regards Reza Toushmalani
  • asked a question related to Meta-Analysis
Question
1 answer
In light of Zhenzhen Pal et al.'s (2023) “Diagnostic Efficacy of Serological Antibody Detection Tests for Hepatitis Delta Virus: A Systematic Review and Meta-Analysis”, I was curious at how serological tests for Hepatitis Delta Virus affect the way we currently manage HDV co-infection with Hepatitis B Virus.
Relevant answer
Good day, Ms. Villacisneros! To answer your question, serological tests for HDV do really help in diagnosing HDV co-infection with Hepatitis B. They help when molecular tests for viral RNA in relation to HDV is not available in some laboratories.
  • asked a question related to Meta-Analysis
Question
1 answer
It is stated in the study titled "Diagnostic Efficacy of Serological Antibody Detection Tests for Hepatitis Delta Virus: A Systematic Review and Meta-Analysis" by Zhenzhen Pan et al. (2023) that hepatitis delta virus (HDV) is a blood-borne pathogen that relies on the envelope protein of hepatitis b virus (HBV) for the assembly and release of infectious virus particles. I am curious on why HDV is dependent on HBV and what are its key viral and host factors.
Relevant answer
Answer
Good day Ms.Sulit!
HBV surface proteins are necessary for the hepatitis D virus (HDV) to produce mature virion particles, which is why HDV is categorized as a satellite virus. As a result, HDV may either co-infect or superinfect with HBV, but it is unable to disseminate or package infectious virions when HBV is not present. Preliminary research using cell cultures and mouse models has shown that encapsulated viruses other than HBV may produce infectious delta virus particles, but as of yet, there is no concrete proof of the therapeutic relevance of these findings. Though they usually recover from both viruses, coinfected patients may experience acute hepatitis. The risk of developing chronic HDV infection and its associated comorbidities increases when an HBV carrier with a chronic infection is superinfected with HDV.