Sampson Twumasi-Ankrah

• Doctor of Philosophy (Statistics) Chartered Economist
• Senior Lecturer at Kwame Nkrumah University of Science and Technology

Background Typhoid fever causes substantial mortality and morbidity in low and middle-income countries (LMICs) as a result of inadequate water, hygiene, and sanitation facilities. The gold standard for typhoid diagnosis is blood culture, however this method is expensive and mostly unavailable in LMICs. Environmental surveillance (ES) could offer a...

Background Limited longitudinal data exist on chronic kidney disease (CKD) in African populations undergoing epidemiological transitions. We investigated incidence, long-term predictors and progression of CKD among Ghanaians residing in Ghana and Ghanaian migrants in the Netherlands (Amsterdam). Methods and findings We analysed data from 2183 part...

Background. Wastewater surveillance offers a valuable approach to the early detection of Typhoid fever. This study evaluates different statistical models for predicting S. Typhi in wastewater samples from Asante Akim, Ghana. Methods. The study was conducted in four towns within the Asante Akim North district of Ghana. Wastewater samples were co...

Background and Aim: Typhoid fever, a significant global health problem, demonstrates a multifaceted transmission pattern. Knowledge of these factors driving the transmission of the infection is critical for developing effective control strategies and resource allocation. This comprehensive desk review aimed at synthesizing evidence from 1928 to 202...

The main objective of the study was to determine the appropriate distribution for extreme rainfall along the coastal and northern sectors of Ghana. For stakeholders and policymakers to make appropriate risk-mitigating measures to lessen the damage caused by flood and drought, it is necessary to make proper inferences about extreme rainfall. In this...

Background Typhoid Fever remains a major cause of morbidity and mortality in low-income settings. The Severe Typhoid in Africa programme was designed to address regional gaps in typhoid burden data and identify populations eligible for interventions using novel typhoid conjugate vaccines. Methods A hybrid design, hospital-based prospective surveil...

Background Salmonella are a group of facultative anaerobic bacteria that belong to the family of Enterobacteriaceae. The common serovars are Salmonella enterica subsp. enterica serovar Typhi which causes typhoid fever and the non-typhoidal Salmonellae (NTS) which are associated with gastroenteritis. Data on the epidemiology and genomic characterist...

Background Conducting vaccine studies in resource-poor settings comes with challenges. These challenges could include lack of infrastructure for cold chain management, accessibility of vaccination centres, the community’s behaviour towards researchers, and political interference. In a pandemic situation e.g., during the Covid-19 peak, overcoming th...

Background Deployment of large-scale surveillance in low-income settings can be challenging. Meanwhile, the inclusion of pharmacists, health centres, over-the-counter medicine sellers (OTC), and herbal clinic practitioners as referral agents for health programs has the potential to improve access to healthcare services, increase enrolment in survei...

Background Setting up a robust typhoid demographic surveillance system (DSS) in low-resource areas will help in characterizing, and defining priorities and strategies for typhoid control activities such as the deployment of new conjugate typhoid vaccines. The study describes the DSS methodology, data, strengths and use in achieving high vaccine cov...

The generalized Pareto distribution is one of the most important distributions in statistics of extremes as it has wide applications in fields such as finance, insurance, and hydrology. This study proposes two new methods for estimating the shape parameter of the generalized Pareto distribution (GPD). The proposed methods use the shrinkage principl...

An expected decline in oil revenue and a complicated global energy market present significant concerns about oil-producing countries’ intentions to move away from fossil fuels. Understanding the dynamics of these concerns, particularly in light of potential energy transitions, is crucial for future energy supply and sustainable energy discussion. G...

Purpose The Research on Obesity and Diabetes among African Migrants (RODAM) prospective (RODAM-Pros) cohort study was established to identify key changes in environmental exposures and epigenetic modifications driving the high burden of cardiovascular disease (CVD) risk among sub-Saharan African migrants. Participants All the participants in the R...

Every child has the right to survive, grow and develop. However, in spite of the considerable global gains that have been made in child survival, Sub-Saharan Africa still has the highest child mortality rates and accounts for the greatest burden of mortality globally. The majority of these children die without ever reaching a health facility. The p...

In numerous investigations, whether practical or theoretical, a requirement for the Analysis of Variance (ANOVA), is that the variances of the measured groups are equal. Many researchers have compared various tests for HOV and drawn conclusions based on the statistical power and weaknesses of those tests without considering the further increase in...

At the heart of the global transition to cleaner energy systems is also an inherent mandate of ensuring a transition to an energy-efficient economy. This study applies a two-regime Markov switching dynamic model to examine the possibility of transitioning to an energy-efficient state, using Ghana as the subject of analysis. Since changes in energy...

Background The rapid advancement of mobile technology has fueled the use of mobile devices for health interventions and for improving healthcare provision in underserved communities. Despite the potential of mHealth being used as a health information and surveillance tool, its scale-up has been challenging and, in most cases, unable to advance beyo...

Background: Understanding the predictive factors for tobacco use, and initiation among the youth is critical for effective intervention and prevention. We, therefore, aimed to determine the profile, associated factors, the regional disparities in the use of tobacco products among the youth in Ghana. Method: The study used the 2017 Ghana Global Yout...

Resistance to Tuberculosis drugs has become a major threat to the control of tuberculosis (TB) globally. We conducted the first nation-wide drug resistance survey to investigate the level and pattern of resistance to first-line TB drugs among newly and previously treated sputum smear-positive TB cases. We also evaluated associations between potenti...

Typhoid fever remains a significant health problem in sub‐Saharan Africa, with incidence rates of >100 cases per 100,000 person‐years of observation. Despite the prequalification of safe and effective typhoid conjugate vaccines (TCV), some uncertainties remain around future demand. Real‐life effectiveness data, which inform public health programs o...

Background The use of a mobile phone-based Interactive Voice Response (mIVR) System for real time monitoring of childhood illnesses provides an opportunity to improve childhood survival and health systems. However, little is known about the factors that facilitate its use. This study sought to identify key determinants and moderators of mIVR system...

This study examined the performance of six outlier detection techniques using a non-stationary time series dataset. Two key issues were of interest. Scenario one was the method that could correctly detect the number of outliers introduced into the dataset whiles scenario two was to find the technique that would over detect the number of outliers in...

This study seeks to determine an appropriate statistical technique for forecasting the cumulated confirm cases of Coronavirus in Ghana. Cumulated daily data spanning from March 12, 2020, to August 04, 2020, was retrieved from the Center for Systems Science and Engineering at Johns Hopkins University. Four statistical forecasting techniques: Autoreg...

The study focused on the Generalized Pareto Distribution (GPD) under the Peak Over Threshold approach (POT). Twenty-one estimation methods were considered for extreme value modeling and their performances were compared. Our goal is to identify the best method in various conditions by the use of a systematic simulation study. Some other estimators w...

Background Global cases of COVID-19 continue to rise, causing havoc to several economies. So far, Ghana has recorded 48,643 confirmed cases with 320 associated deaths. Although summaries of data are usually provided by the Ministry of Health, detailed epidemiological profile of cases are limited. This study sought to describe the socio-demographic...

Unit root tests for stationarity have relevancy in almost every practical time series analysis. Deciding on which unit root test to use is a topic of active interest. In this study, we compare the performance of the three commonly used unit root tests (i.e., Augmented Dickey-Fuller (ADF), Phillips-Perron (PP), and Kwiatkowski Phillips Schmidt and S...

: Hunger is on the rise in almost all sub-regions of Africa, where the prevalence of undernourishment has reached levels of 22.8 percent in sub-Saharan Africa. Therefore, the purpose of this study is to examine the effect of economic growth and climatic factors on food security in Ghana using different functional forms of regression analysis. Annua...

Introduction: The Global Youth Tobacco Survey’s findings have been used to support Ghana’s tobacco control legislation, monitor tobacco use among the youth and also used in meeting various Articles of the World Health Organization (WHO) Framework Convention on Tobacco Control (FCTC). These Articles include: Article 8 (Protection for exposure to tob...

INTRODUCTION Ghana has a partial smoking ban with smoking allowed in designated smoking areas. Studies evaluating smoke-free laws are scarce in Sub-Saharan Africa. Evaluation of smoke-free laws is an effective means of measuring progress towards a smoke-free society. This study assessed the level of compliance to the provisions of the current smok...

Background: Praziquantel (PZQ) is the standard treatment for Schistosomiasis in sub-Saharan Africa. However, there is evidence suggesting praziquantel treatment failure in Schistosome infections with associated potential renal impairment. The objective of this study was to determine the effect of three monthly doses of 60 mg/kg/day PZQ on schistos...

In numerous investigates, regardless of whether or not beneficial or hypothetical, an inquiry that emerges in performing examination of change is the Homogeneity of Variance suspicion. Severa analysts have checked out terrific assessments for trying out homogeneity of fluctuation and reached determinations dependent on the power and shortcomings of...

Background: The widespread use of social media applications on mobile phones indicate that smart phones have become more than just a simple medium for voice calling. Several studies have shown the potential benefit of these social media applications in discussing many health conditions. We report on tracking sample transport by public and private t...

In this study, we propose a new information criterion for model selection in univariate time series analysis. This is done by weighting the penalty terms of the three most commonly used information criteria (i.e. Akaike Information Criterion (AIC), Schwarz Information Criterion (SIC) and Hannan Quinn Information Criterion (HQ)). The penalties of th...

The profitability of a mine today is dependent on the careful management of its operations. The study seeks to examine the effect of availability and utilization on mine production. Daily data used in this study spanned from January 2016 to June 2016 were queried from the Modular fleet management system (FMS) at the Anglogold Ashanti Iduapriem Limi...

In this paper, we are interested in two main issues concerning how missing values should be treated in univariate time series. Firstly, three different error metrics are examined to know which one is appropriate for the different characteristics in univariate time series data in context of imputation techniques. Secondly, the performance of nine di...

This study examined the combined effect of socio-economic and climatic variables on Ghana’s cocoa production. First, only multiple regression analysis was applied to all the variables affecting cocoa production which caused multicollinearity problems. In order to eliminate multicollinearity problems and perform a reliable regression, factor analysi...

Background and Aim: The purpose of this study was to determine an appropriate statistical technique for forecasting the monthly Malaria cases in Ghana. Methods and Materials: Monthly data spanning from January 2008 to December 2017 were obtained from the District Health Information Management System (DHIMS) 2, Ghana Health Service. The four competi...

Background: The widespread use of social media applications on mobile phones indicate that smart phones have become more than just a simple medium for voice calling. Several studies have shown the potential benefit of these social media applications in discussing many health conditions. We report on tracking sample transport by public and private t...

Abstract: This paper focuses on modeling the extreme maximum temperature in Ghana using the extreme value theory. This is to inform decision-makers to help them plan appropriate risk mitigating measures to reduce the damage caused by drought. The block maxima with Generalized Extreme Value (GEV) and the General Pareto (GP) (with “all excesses” and...

Although different types of efficient vectors’ median filters have been proposed in literature, researchers have not resolved the problem identified in vector filters: (i) detecting impulse noise in individual color component with the smallest dissimilarity measure in the window; (ii) detecting impulsive pixels in regions of highly dense impulse no...

The main purpose of this paper is to analyse and model the price volatility in petroleum products in Ghana. A historical data on monthly petroleum products (kerosene, gas oil, LPG and premium gasoline) spanning from August,2007 to February, 2016 were used in this study. The methods used were the trend analysis and Generalized Auto-Regression Condit...

In this study, we explore the causal influence of export earnings of cocoa towards economic growth (i.e., gross domestic product (GDP)). The augmented Dickey–Fuller (ADF) and the Phillips–Perron (PP) unit root tests indicate that the two series are integrated of order one, I (1). The results of the trace and the maxi-eigenvalue cointegration test b...

The major problem affecting poor people in developing countries has been food insecurity, while households living in poverty have continued to be vulnerable in their situation. Nigeria, being the most populous country in Africa with an urban population growing at an exponential rate, the government's objective of achieving food self-security is a m...

In model building, the model with appropriate number of parameters needs to be identified. Thus, a variety of information criteria have already been developed, each with a different background to handle this challenge. The mostly used information criteria are the Akaike Information Criterion (AIC), Schwarz Information Criterion (SIC), and Hannan an...

This paper extends the standard approach of combining forecast by proposing weights which are based on ranking the performance of forecast accuracy measures of models. These weights became necessary due to the problems associated with the Akaike weights, equal weights and forecast from the ‘best’ model selected by the minimum AICc value; which are...

In this paper, we develop models for forecasting the annual cocoa production in Ghana. Instead of using the ‘best’ model for forecasting; a weighted scheme was applied to all competing models, to obtain a weighted model. The weighted scheme used in this paper is the weighted ranking procedure. Annual production, export earnings, exchange rate and d...

In this paper, we develop models for forecasting the annual cocoa production in Ghana. Instead of using the 'best' model for forecasting; a weighted scheme was applied to all competing models, to obtain a weighted model. The weighted scheme used in this paper is the weighted ranking procedure. Annual production, export earnings, exchange rate and d...

This study examines the impact of HIV/ AIDS scourge on economic growth of some selected Sub-Sahara African countries. The three sub-Sahara African regions (Southern, West and Eastern) are categorized into lowest and highest HIV prevalence rate, using the global report of the UNAIDS 2012 data. In each region, the lowest and the highest HIV prevalenc...