Degree Discipline

Determination of the Optimal Number of Strata for Bias Reduction in Propensity Score Matching. (open access)

Determination of the Optimal Number of Strata for Bias Reduction in Propensity Score Matching.

Previous research implementing stratification on the propensity score has generally relied on using five strata, based on prior theoretical groundwork and minimal empirical evidence as to the suitability of quintiles to adequately reduce bias in all cases and across all sample sizes. This study investigates bias reduction across varying number of strata and sample sizes via a large-scale simulation to determine the adequacy of quintiles for bias reduction under all conditions. Sample sizes ranged from 100 to 50,000 and strata from 3 to 20. Both the percentage of bias reduction and the standardized selection bias were examined. The results show that while the particular covariates in the simulation met certain criteria with five strata that greater bias reduction could be achieved by increasing the number of strata, especially with larger sample sizes. Simulation code written in R is included.
Date: May 2010
Creator: Akers, Allen
System: The UNT Digital Library
Convergent Validity of Variables Residualized By a Single Covariate: the Role of Correlated Error in Populations and Samples (open access)

Convergent Validity of Variables Residualized By a Single Covariate: the Role of Correlated Error in Populations and Samples

This study examined the bias and precision of four residualized variable validity estimates (C0, C1, C2, C3) across a number of study conditions. Validity estimates that considered measurement error, correlations among error scores, and correlations between error scores and true scores (C3) performed the best, yielding no estimates that were practically significantly different than their respective population parameters, across study conditions. Validity estimates that considered measurement error and correlations among error scores (C2) did a good job in yielding unbiased, valid, and precise results. Only in a select number of study conditions were C2 estimates unable to be computed or produced results that had sufficient variance to affect interpretation of results. Validity estimates based on observed scores (C0) fared well in producing valid, precise, and unbiased results. Validity estimates based on observed scores that were only corrected for measurement error (C1) performed the worst. Not only did they not reliably produce estimates even when the level of modeled correlated error was low, C1 produced values higher than the theoretical limit of 1.0 across a number of study conditions. Estimates based on C1 also produced the greatest number of conditions that were practically significantly different than their population parameters.
Date: May 2013
Creator: Nimon, Kim
System: The UNT Digital Library
Using Posterior Predictive Checking of Item Response Theory Models to Study Invariance Violations (open access)

Using Posterior Predictive Checking of Item Response Theory Models to Study Invariance Violations

The common practice for testing measurement invariance is to constrain parameters to be equal over groups, and then evaluate the model-data fit to reject or fail to reject the restrictive model. Posterior predictive checking (PPC) provides an alternative approach to evaluating model-data discrepancy. This paper explores the utility of PPC in estimating measurement invariance. The simulation results show that the posterior predictive p (PP p) values of item parameter estimates respond to various invariance violations, whereas the PP p values of item-fit index may fail to detect such violations. The current paper suggests comparing group estimates and restrictive model estimates with posterior predictive distributions in order to demonstrate the pattern of misfit graphically.
Date: May 2017
Creator: Xin, Xin
System: The UNT Digital Library
Structural Validity and Item Functioning of the LoTi Digital-Age Survey. (open access)

Structural Validity and Item Functioning of the LoTi Digital-Age Survey.

The present study examined the structural construct validity of the LoTi Digital-Age Survey, a measure of teacher instructional practices with technology in the classroom. Teacher responses (N = 2840) from across the United States were used to assess factor structure of the instrument using both exploratory and confirmatory analyses. Parallel analysis suggests retaining a five-factor solution compared to the MAP test that suggests retaining a three-factor solution. Both analyses (EFA and CFA) indicate that changes need to be made to the current factor structure of the survey. The last two factors were composed of items that did not cover or accurately measure the content of the latent trait. Problematic items, such as items with crossloadings, were discussed. Suggestions were provided to improve the factor structure, items, and scale of the survey.
Date: May 2011
Creator: Mehta, Vandhana
System: The UNT Digital Library
Spatial Ability, Motivation, and Attitude of Students as Related to Science Achievement (open access)

Spatial Ability, Motivation, and Attitude of Students as Related to Science Achievement

Understanding student achievement in science is important as there is an increasing reliance of the U.S. economy on math, science, and technology-related fields despite the declining number of youth seeking college degrees and careers in math and science. A series of structural equation models were tested using the scores from a statewide science exam for 276 students from a suburban north Texas public school district at the end of their 5th grade year and the latent variables of spatial ability, motivation to learn science and science-related attitude. Spatial ability was tested as a mediating variable on motivation and attitude; however, while spatial ability had statistically significant regression coefficients with motivation and attitude, spatial ability was found to be the sole statistically significant predictor of science achievement for these students explaining 23.1% of the variance in science scores.
Date: May 2011
Creator: Bolen, Judy Ann
System: The UNT Digital Library
Construct Validation and Measurement Invariance of the Athletic Coping Skills Inventory for Educational Settings (open access)

Construct Validation and Measurement Invariance of the Athletic Coping Skills Inventory for Educational Settings

The present study examined the factor structure and measurement invariance of the revised version of the Athletic Coping Skills Inventory (ACSI-28), following adjustment of the wording of items such that they were appropriate to assess Coping Skills in an educational setting. A sample of middle school students (n = 1,037) completed the revised inventory. An initial confirmatory factor analysis led to the hypothesis of a better fitting model with two items removed. Reliability of the subscales and the instrument as a whole was acceptable. Items were examined for sex invariance with differential item functioning (DIF) using item response theory, and five items were flagged for significant sex non-invariance. Following removal of these items, comparison of the mean differences between male and female coping scores revealed that there was no significant difference between the two groups. Further examination of the generalizability of the coping construct and the potential transfer of psychosocial skills between athletic and academic settings are warranted.
Date: May 2017
Creator: Sanguras, Laila Y., 1977-
System: The UNT Digital Library