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Description
The comparison of between- versus within-person relations addresses a central issue in psychological research regarding whether group-level relations among variables generalize to individual group members. Between- and within-person effects may differ in magnitude as well as direction, and contextual multilevel models can accommodate this difference. Contextual multilevel models have been

The comparison of between- versus within-person relations addresses a central issue in psychological research regarding whether group-level relations among variables generalize to individual group members. Between- and within-person effects may differ in magnitude as well as direction, and contextual multilevel models can accommodate this difference. Contextual multilevel models have been explicated mostly for cross-sectional data, but they can also be applied to longitudinal data where level-1 effects represent within-person relations and level-2 effects represent between-person relations. With longitudinal data, estimating the contextual effect allows direct evaluation of whether between-person and within-person effects differ. Furthermore, these models, unlike single-level models, permit individual differences by allowing within-person slopes to vary across individuals. This study examined the statistical performance of the contextual model with a random slope for longitudinal within-person fluctuation data.

A Monte Carlo simulation was used to generate data based on the contextual multilevel model, where sample size, effect size, and intraclass correlation (ICC) of the predictor variable were varied. The effects of simulation factors on parameter bias, parameter variability, and standard error accuracy were assessed. Parameter estimates were in general unbiased. Power to detect the slope variance and contextual effect was over 80% for most conditions, except some of the smaller sample size conditions. Type I error rates for the contextual effect were also high for some of the smaller sample size conditions. Conclusions and future directions are discussed.
ContributorsWurpts, Ingrid Carlson (Author) / Mackinnon, David P (Thesis advisor) / West, Stephen G. (Committee member) / Grimm, Kevin J. (Committee member) / Suk, Hye Won (Committee member) / Arizona State University (Publisher)
Created2016
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Description
Socioeconomic status (SES) is linked with poorer health outcomes across the range of SES. The Reserve Capacity Model (RCM) proposes that low SES fuels repeated and/or chronic exposure to elevated levels of stress, producing deleterious emotional, psychological, social, and physiological changes that result in development of disease over time. The

Socioeconomic status (SES) is linked with poorer health outcomes across the range of SES. The Reserve Capacity Model (RCM) proposes that low SES fuels repeated and/or chronic exposure to elevated levels of stress, producing deleterious emotional, psychological, social, and physiological changes that result in development of disease over time. The RCM further asserts that a relative lack of social and psychological resources, including efficacy and social support, among low SES individuals accounts for their greater vulnerability to the effects of stress. Although the links between stress, reserve capacity, and health outcomes are framed in the RCM as an ongoing process that produces disease, the majority of investigations testing the model have not examined its utility in explaining 1) coping with daily stressors or 2) symptom flares among individuals managing a chronic illness. This study investigated the effects of SES, reflected in income level, on the: 1) levels of daily financial events and financial worry; 2) relations between daily financial worry and symptoms of pain and fatigue; and 3) extent to which daily coping efficacy and social support mediated the daily financial worry-symptom relation across 21 daily diary reports collected from 220 individuals with fibromyalgia (FM). Simple correlations showed that income was inversely related to frequency of financial events and level of financial worry across 21 days. Results from multilevel models indicated that daily increases in financial worry were unrelated to pain regardless of income level, but were related to increased fatigue among individuals with lower relative to higher income. Daily efficacy and support mediated the relations between financial worry and pain and fatigue, but the extent of mediation did not differ based on high versus low income level. Taken together, the findings suggest that individuals of low versus high income encounter more frequent financial stress and experience greater daily fatigue exacerbation related to that stress, in line with the RCM. Over time, the greater exposure and reactivity to financial strain may account for the inverse relation between income and disability among those with chronic pain.
ContributorsMoore, Shannon Victoria (Author) / Davis, Mary C. (Thesis advisor) / Luecken, Linda J. (Committee member) / Suk, Hye Won (Committee member) / Arizona State University (Publisher)
Created2017