Shelley A. Blozis

University of California, Davis | UCD · Department of Psychology

Self-report data are regularly used in marketing research when consumer perceptions are central to understanding consumer responses to marketing efforts. Self-report data are convenient and cost-effective. A widely known response bias that is inherent to self-report data and illuminated by daily diary data is a tendency of the first report by study...

Self-report data are essential in health psychology research where an individual’s perception is critical to understanding one’s health and psychological status. Intensive data collection over time, including daily diary assessments, is necessary in understanding within- and between-person variability in health and psychological processes over time...

Health, function, and social participation (e.g., disablement) were studied among community living men and women with mobility limitations living in central Mexico. Psychological (i.e., depression and activity effort), cultural (i.e., attitudes toward assistive devices) and social (i.e., personal resources) variables were tested with the goal to id...

In public health research an increasing number of studies is conducted in which intensive longitudinal data is collected in an experience sampling or a daily diary design. Typically, the resulting data is analyzed with a mixed‐effects model or mixed‐effects location scale model because they allow one to examine a host of interesting longitudinal re...

The life-history narratives of 10 Mexican American men with mobility limitations, age 55-77 years (mean = 63.8, SD = 5.8), were explored using a qualitatively driven, life-history mixed-methods study to understand perceptions of mobility limitations over the life course. Within that methodological and paradigmatic framework, conceptualizations of a...

Background: A gap in research about the trajectories of function among men and women aging with functional limitations because of multiple sclerosis (MS) hinders ability to plan for future needs. Objectives: Using a biopsychosocial model, we characterize how men and women with MS report changes over time in their function and test how person-lev...

The current research examines the options available for political candidates to leverage their brand in order to influence voting intentions. Candidates, owing to the strong psychological connections they establish with their voters, are well-positioned to construct brand equity. Emotions are part of any brand-consumer relationship, but in the case...

Mixed-effects models for repeated measures and longitudinal data include random coefficients that are unique to the individual, and thus permit subject-specific growth trajectories, as well as direct study of how the coefficients of a growth function vary as a function of covariates. Although applications of these models often assume homogeneity of...

Valid inference can be drawn from a random-effects model for repeated measures that are incomplete if whether the data are missing or not, known as missingness, is independent of the missing data. Data that are missing completely at random or missing at random are two data types for which missingness is ignorable. Given ignorable missingness, stati...

A Napa Valley Sauvignon blanc wine was bottled with 200 each of a natural cork, a screw cap, and a synthetic cork. As browning is an index for wine oxidation, we assessed the brown color of each bottle with a spectrophotometer over 30 months. A random-effects regression model for longitudinal data on all bottles and closure groups found a browning...

Coppery titi monkeys maintain pair bonds through affiliative behaviours (e.g. tail twining, maintaining social proximity). Findings from previous studies suggest that the amount of time pairs spend in affiliative contact is not stable over time within pairs and differs across pairs. The present study investigates several predictors (temperament, ag...

Multilevel models are effective marketing analytic tools that can test for consumer differences in longitudinal data. A two-part multilevel model is a special case of a multilevel model developed for semi-continuous data, such as data that include a combination of zeros and continuous values. For repeated measures of media use data, a two-part mult...

There are massive literatures on initial attraction and established relationships. But few studies capture early relationship development: the interstitial period in which people experience rising and falling romantic interest for partners who could—but often do not—become sexual or dating partners. In this study, 208 single participants reported o...

A mixed-effects location scale model allows researchers to study within- and between-person variation in repeated measures. Key components of the model include separate variance models to study predictors of the within-person variance, as well as predictors of the between-person variance of a random effect, such as a random intercept. In this paper...

Children’s nighttime fear is hypothesized as a cognitive relict reflecting a long history of natural selection for anticipating the direction of nighttime predatory attacks on the presumed human ancestor, Australopithecus afarensis , whose small-bodied females nesting in trees would have anticipated predatory attacks from below. Heavier males nesti...

Background Over 5 million Americans age 65 years and older were diagnosed with Alzheimer's disease and/or related dementia (ADRD), a majority of whom exhibit behavioral and psychological symptoms leading to placement in long-term care settings. These facilities need nonmedical interventions, and music-based programs have received supportive evidenc...

Health Psychology has received numerous papers over the past several months on topics related to the COVID-19 pandemic. Many of them concern depression, anxiety, stress, or other forms of distress in the general population or in health care workers. We have received far fewer papers on COVID-related health behaviors and health communications-factor...

Brand related goals in the online environment are consistent with those of the retail environment: providing products and services that ultimately convert customers into brand loyal customers. Investigating the components of e-loyalty may be a way to improve it. Using a Spanish sample, this study investigates a nine-dimension, latent variable model...

Piecewise latent growth models (LGMs) for linear-linear processes have been well-documented and studied in recent years. However, in the latent growth modeling literature, advancements to other functional forms as well as to multiple changepoints or knots have been nearly non-existent. This manuscript deals with three extensions. The first is to a...

Prior research has identified perceived discrimination as being a contributing factor in health and mental health disparities. However, there is little research on the relationship between perceived discrimination and behaviors such as hazardous alcohol and illicit substance use and risky sexual behaviors that put people at risk for negative health...

The Brazelton Neonatal Behavioral Assessment Scale (NBAS) evaluates a newborn infant's autonomic, motor, state, temperament, and social-attentional systems, which can help to identify infants at risk of developmental problems. Given the prevalence of rhesus monkeys being used as an animal model for human development, here we aimed to validate a sta...

Longitudinal time use data afford the opportunity to study within- and between-individual differences, but can present challenges in data analysis. Often the response set includes a large number of zeros representing those who did not engage in the target behavior. Coupled with this is a continuous measure of time use for those who did engage. The...

This study supports a strategic analytics proposal, namely that there is conceptual and practical utility in applying a two-part mixed-effects model for understanding individual differences in daily media use. Individual-level daily diary measures of media use typically contain information about a person’s likeliness to use media, extent of usage,...

We extend our ongoing investigations of the health effects of activity effort among Mexican Americans (MA) with mobility limitations, specifically those with osteoarthritis (OA) (Harrison, 2009). Our previous research linked activity effort with co-morbidity and social participation in women with mobility limitations, finding significant variations...

The Patient-Reported Outcomes Measurement Information System® (PROMIS®) is a collection of person-centered measures of physical, mental, and social health in children and adults. Developed using state-of-the-art psychometric methods, these measures are offered as fixed-length questionnaires and computerized adaptive tests, with translations availab...

Our purpose is to explore perceived satisfaction with pain management among residents of long-term care (LTC) facilities, with hospice/palliative care (HPC) hypothesized to improve services. The 22 RNs used tablets to review charts; speak to facility administrators, and interview residents / family. Analyses included random-effects logistic model....

Objective: The interaction between task based urinary incontinence (UI) care and resident caregiver relational interactions is examined to understand how they contribute to the overall emergence of quality in nursing facilities. Design and Methods: Data came from 1560 residents living in 815 Texas nursing facilities. We performed chart reviews usin...

Quality of care for residents with urinary incontinence (UI) living in nursing facilities was analyzed using data collected from 815 facilities for the Nursing Facility Quality Review in Texas. Overall, of the 1,560 residents, 48.4% (n = 755) experienced UI. The risk of developing UI over a ten-year-period in a nursing facility was 6%. Only 54% of...

Nonlinear mixed-effects models are models in which one or more coefficients of the growth model enter in a nonlinear manner, such as appearing in the exponent of the growth function. In their applications, the within-individual residuals are often assumed to be independent with constant variance across time, an assumption that implies that the assu...

Objective: To examine ethnic identity and ethnic socialization as potential protective factors for risk behaviors among U.S. college students. Participants: Participants were 398 African American and Afro-Caribbean students recruited from 30 colleges and universities September 2008 - October 2009. Methods: Data on hazardous alcohol use, substa...

Nursing homes are the major provider of intermediate and long-term care outside of the hospital setting to individuals whose capacity for self-care is limited due to physical or cognitive impairments. Yet, despite their need for assistance, residents of nursing homes want to control their lives, set their routines, and do enjoyable things. The exte...

Nonlinear mixed-effects (NLME) models are used when analyzing continuous repeated measures data taken on each of a number of individuals where the focus is on characteristics of complex, nonlinear individual change. Challenges with fitting NLME models and interpreting analytic results have been well documented in the statistical literature. However...

Importance: Human health is adversely impacted by viruses that establish lifelong infections that are often accompanied with increased morbidity and mortality (e.g., infections with HIV, hepatitis C virus, or human cytomegalovirus). A longstanding but unfulfilled goal has been to develop postinfection vaccine strategies that could "reboot" the imm...

Objective: We examined whether two key emotion regulation strategies, cognitive reappraisal and expressive suppression, moderated the relations between discrimination (i.e., foreigner objectification and general denigration) and adjustment. Methods: Participants were U.S. Latino/a and Asian-heritage college students (N = 1,279, 67% female, 72% U...

Nonlinear models are effective tools for the analysis of longitudinal data. These models provide a flexible means for describing data that follow complex forms of change. Exponential and logistic functions that include a parameter to represent an asymptote, for instance, are useful for describing responses that tend to level off with time. There ar...

This review is published in Structural Equation Modeling: A Multidisciplinary Journal Volume 23, Issue 4, 2016 Book Review Review of Growth Curve Modeling: Theory and Applications, Michael J. Panik. Hoboken, NJ: Wiley, 2014, 454 pp, $134 Hardcover, $107.99 E-Book. Reviewed by Nathan B. Smith and Shelley A. Blozis University of California, Davis Mic...

Background: Multiple sclerosis (MS), a chronic neurological disease typically diagnosed in young adulthood, presents with a wide variety of symptoms, impairments and functional limitations. Given the chronic, unpredictable and long-term nature of this disease, preserving function is essential. Objective: The purpose of this study was to identify...

Objectives: Past research has established that the Multigroup Ethnic Identity Measure (MEIM) exhibits measurement invariance across diverse ethnic groups. However, relatively little research has evaluated whether this measure is invariant across generational status. Thus, the present study evaluates the invariance of the MEIM across foreign-born, s...

Ethnic identity has been shown to play an important role in Hispanic consumer behavior research. The measurement and statistical treatment of ethnic identity measures, however, have been mixed across studies. First, the operationalization of ethnic identity has varied with some studies defining the construct by behaviors (e.g., language use) and ot...

Ethnic identity has been instrumental in understanding individual differences in consumer behaviour. The Multigroup Ethnic Identity Measure (MEIM) is a theoretically based instrument that is frequently used in cultural consumer behaviour research. The manner in which the MEIM has been used in research has varied across studies. Identifying the most...

Latent curve models have become a popular approach to the analysis of longitudinal data. At the individual level the model expresses an individual's response as a linear combination of what are called `basis functions' that are common to all members of a population and weights that may vary among individuals. This paper uses differential calculus t...

The growing recognition that social needs of primates in captivity must be addressed can present challenges to staff at primate facilities charged with implementing pair-housing solutions for animals. Unfortunately, there are few published papers that identify individual characteristics that might facilitate the social pairing process, and those th...

Background: Type 2 diabetes mellitus is a worldwide challenge. Practice guidelines promote structured self-monitoring of blood glucose (SMBG) for informing health care providers about glycemic control and providing patient feedback to increase knowledge, self-efficacy, and behavior change. Paired glucose testing—pairs of glucose results obtained b...

Ordinal response scales are often used to survey behaviors, including data collected in longitudinal studies. Advanced analytic methods are now widely available for longitudinal data. This study evaluates the performance of 4 methods as applied to ordinal measures that differ by the number of response categories and that include many zeros. The met...

This study of a cohort of 451 adolescents examined associations between trajectories of problem behaviors and the timing of entry into work, marriage, and parenthood. We used data from 12 assessments across adolescence, through emerging adulthood and into young adulthood. We employed 2-phase mixed-effects models to estimate growth in substance use...

This brief research report shows how different applications of the Multigroup Ethnic Identity Measure (MEIM) can have implications for the interpretation of the role of ethnic identity in research. Throughout the MEIM’s widespread use, notable inconsistencies lie in how the measure has been applied. This report uses empirical data to demonstrate di...

Data analysis with incomplete data is common in prevention research. Appropriate applications of methods to handle missing data can be critical to ensuring unbiased parameter estimates, as well as maintaining optimal efficiency in parameter estimates. The primary challenge for researchers concerns the particular analytic method that is deemed neces...

A 2-part latent growth model can be used to analyze semicontinuous data to simultaneously study change in the probability that an individual engages in a behavior, and if engaged, change in the behavior. This article uses a Monte Carlo (MC) integration algorithm to study the interrelationships between the growth factors of 2 variables measured long...

This volume just won a 2015 Choice Outstanding Academic Title award from the American Library Association. Summary of volume: Statistics is the field of knowledge concerned with data collection, data analysis, and data interpretation and presentation. Methodology comprises the many and varied structured ways in which research is conducted -- answer...

Missing data are common in studies that rely on multiple informant data to evaluate relationships among variables for distinguishable individuals clustered within groups. Estimation of structural equation models using raw data allows for incomplete data, and so all groups may be retained even if only one member of a group contributes data. Statisti...

The 2011 Residential Summer Solutions Study compared the hourly load effects of three different real-time information treatments and two program options. The information treatments included: Baseline information (no real-time data), real-time Home information (whole-house data), and real-time Appliance information (data for the whole house plus thr...

Nonlinear mixed-effects (NLME) models remain popular among practitioners for analyzing continuous repeated measures data taken on each of a number of individuals when interest centers on characterizing individual-specific change. Within this framework, variation and correlation among the repeated measurements may be partitioned into interindividual...

This article reports the experiences of women aged 55 to 75 with mobility impairments who attributed aspects of their limitations to workplace injuries and provides insight into worker's compensation policies. The study sample includes Mexican American (MA) and non-Hispanic White (NHW) women aged 55 to 75 who participated in a 4-year ethnographic s...

SAS PROC NLMIXED was developed for the estimation of nonlinear mixed models, including both multilevel and longitudinal data. Nonlinear mixed models are models for which a random coefficient may enter an equation nonlinearly. PROC NLMIXED may be used to estimate models for which a response follows a normal, binomial, or Poisson distribution, as wel...

Purpose: To examine predictors of psychotherapy outcomes, focusing on client characteristics that are especially salient for culturally diverse clients. Method: Sixty clients (31 women; 27 White Americans, 33 Asian Americans) participated in this treatment study. Client characteristics were measured at pretreatment, and outcomes were measured po...

Ketamine is an N-methyl-D-aspartate (NMDA) receptor antagonist that is used in anesthetic, abuse, and therapeutic contexts. Recent evidence suggests that ketamine may affect not only glutamate systems, but may also act on receptors in the dopamine and serotonin systems. Because monoamine neurotransmitters play important trophic roles in prenatal de...

Mixed models are used for the analysis of data measured over time to study population-level change and individual differences in change characteristics. Linear and nonlinear functions may be used to describe a longitudinal response, individuals need not be observed at the same time points, and missing data, assumed to be missing at random (MAR), ma...

To examine the effects of a wellness intervention, Lifestyle Counts, for women with fibromyalgia syndrome on the level of self-efficacy for health-promoting behaviours, health-promoting activity and perceived quality of life. A randomized controlled single-blinded trial with treatment and attention-control groups. Community in the southwestern Unit...

In non-human primate models of AIDS, attenuated lentiviruses provide the most reliable protection from challenge with pathogenic virus but the extent to which the vaccine virus replicates after challenge is unclear. At 7 and 14 days after vaginal challenge with pathogenic SIVmac239, plasma SIVenv RNA levels were significantly lower in female macaqu...

Simian immunodeficiency virus (SIV) infection of rhesus macaques is a valuable animal model for human immunodeficiency virus (HIV)-1 vaccine development. Our laboratory recently described the immunogenicity and limited efficacy of a vif-deleted SIVmac239 proviral DNA (SIV/CMVDelta vif) vaccine. The current report characterizes immunogenicity and ef...

The potential benefit of using unmethylated CpG oligoribodeoxynucleotides (ODN) as an adjuvant in a therapeutic simian immunodeficiency virus (SIV) vaccine consisting of AT2-inactivated SIVmac239 was evaluated in SIV-infected rhesus macaques receiving antiretroviral therapy (ART). We hypothesized that using CpG ODN as an adjuvant in therapeutic vac...

What role does a man's intelligence play in women's mate preferences? Selecting a more intelligent mate often provides women with better access to resources and parental investment for offspring. But this preference may also provide indirect genetic benefits in the form of having offspring who are in better physical condition, regardless of parenta...

The purpose of the study was to explore the impact of change in functional limitation (FL), controlling for social support (SS), on attitudes toward aging using longitudinal survey data collected over a 7-year period. The 503 women with multiple sclerosis (MS; age, M=57 years, SD=10.25) were mostly Anglo (93%) and married (69%). First, the authors...

From the beginning of the AIDS epidemic, stress has been a suspected contributor to the wide variation seen in disease progression, and some evidence supports this idea. Not all individuals respond to a stressor in the same way, however, and little is known about the biological mechanisms by which variations in individuals' responses to their envir...

The coding of time in latent curve models has been shown to have important implications in the interpretation of growth parameters. Centering time is often done to improve interpretation but may have consequences for estimated parameters. This article studies the effects of coding and centering time when there is interindividual heterogeneity in ti...

Latent curve models offer a flexible approach to the study of longitudinal data when the form of change in a response is nonlinear. This article considers such models that are conditionally linear with regard to the random coefficients at the 2nd level. This framework allows fixed parameters to enter a model linearly or nonlinearly, and random coef...

Acceptance of chronic conditions often has been studied from the perspective of grief and loss. This paper presents a new conceptualization of acceptance of chronic conditions that is grounded in the perspective of those living with a chronic condition and focuses on adaptation to and acceptance of change in one's life. Data obtained from a sample...

This article reviews Newton procedures for the analysis of mean and covariance structures that may be functions of parameters that enter a model nonlinearly. The kind of model considered is a mixed-effects model that is conditionally linear with regard to its parameters. This means parameters entering the model nonlinearly must be fixed, whereas th...

Postnatal developmental stages of lung parenchyma in rhesus monkeys is about one-third that of humans. Alveoli in humans are reported to be formed up to 8 yr of age. We used design-based stereological methods to estimate the number of alveoli (N(alv)) in male and female rhesus monkeys over the first 7 yr of life. Twenty-six rhesus monkeys (13 males...

Refractory periods at the onset of dispersal occur when individuals initially do not settle in response to cues from naturally occurring habitats. The current paper focuses on relationships between refractory periods and habitat selection behaviour when natal dispersers use sequential search tactics. We first show how individual differences in acce...

Latent growth curve modeling employed data from a longitudinal study of 451 sibling families to examine parents, siblings, and family economics as factors in individual differences in the developmental course of interpersonal aggression during adolescence. Findings suggest that individual change in interpersonal aggression during adolescence can be...

Progesterone administration prior to intravaginal challenge with pathogenic SIVmac239 decreases the protective efficacy of live attenuated vaccines in rhesus macaques. To determine if progesterone alters the efficacy of live attenuated vaccines through local or systemic effects, seven male rhesus macaques were immunized with SHIV89.6 and then chall...

Latent curve models have become a useful approach to analyzing longitudinal data, due in part to their allowance of and emphasis on individual differences in features that describe change. Common applications of latent curve models in developmental studies rely on polynomial functions, such as linear or quadratic functions. Although useful for desc...

To better understand the roles that hormones and experience play in infant survival and maternal behavior in a biparental primate species, we analyzed urinary estrone (E 1 C) and pregnanediol glu-curonide (PdG) from 24 socially housed titi monkey (Callicebus cupreus) females over 54 pregnancies (N = 1,430 samples). Pregnancies were categorized acco...

This article shows how nonlinear latent curve models may be fitted for simultaneous analysis of multiple variables measured longitudinally using Mx statistical software. Longitudinal studies often involve observation of several variables across time with interest in the associations between change characteristics of different variables measured wit...