UNT Theses and Dissertations - 2 Matching Results

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Comparison of Heterogeneity and Heterogeneity Interval Estimators in Random-Effects Meta-Analysis

Description: Meta-analyses are conducted to synthesize the quantitative results of related studies. The random-effects meta-analysis model is based on the assumption that a distribution of true effects exists in the population. This distribution is often assumed to be normal with a mean and variance. The population variance, also called heterogeneity, can be estimated numerous ways. Accurate estimation of heterogeneity is necessary as a description of the distribution and for determining weights applied in the estimation of the summary effect when using inverse-variance weighting. To evaluate a wide range of estimators, we compared 16 estimators (Bayesian and non-Bayesian) of heterogeneity with regard to bias and mean square error over conditions based on reviews of educational and psychological meta-analyses. Three simulation conditions were varied: (a) sample size per meta-analysis, (b) true heterogeneity, and (c) sample size per effect size within each meta-analysis. Confidence or highest density intervals can be calculated for heterogeneity. The heterogeneity estimators that performed best over the widest range of conditions were paired with heterogeneity interval estimators. Interval estimators were evaluated based on coverage probability, interval width, and coverage of the estimated value. The combination of the Paule Manel estimator and Q-Profile interval method is recommended when synthesizing standardized mean difference effect sizes.
Date: May 2018
Creator: Boedeker, Peter
Partner: UNT Libraries

Developing a Self-Respect Instrument to Distinguish Self-Respect from Self-Esteem

Description: Throughout the scientific literature, researchers have referred to self-respect and self-esteem as being the same construct. However, the present study advocated that they exist as two distinct constructs. In this quantitative study, an instrument was developed to measure self-respect as a construct, and subsequently distinguish that self-respect is distinct from the construct of self-esteem. Exploratory factor analyses (EFA) indicated 32.60% of the variance was accounted for by the 11-item Jefferson Self-Respect instrument (JSR), which measured self-respect as a unidimensional construct. The reliability estimate of the scores from the JSR reached an acceptable α = .82. Fit indices (RMSEA = .031, SRMR = .037, CFI = .982, and TLI = .977) from the confirmatory factor analyses (CFA) signified a well-fitted hypothesized model of self-respect that existed as a unidimensional construct. Additionally, the CFA revealed that the construct of self-respect, and self-esteem was generally distinct, and the strength of the correlation between the two constructs was moderately positive (r = .62).
Date: August 2017
Creator: Jefferson, Sean G
Partner: UNT Libraries