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Missing Data Treatments at the Second Level of Hierarchical Linear Models (open access)

Missing Data Treatments at the Second Level of Hierarchical Linear Models

The current study evaluated the performance of traditional versus modern MDTs in the estimation of fixed-effects and variance components for data missing at the second level of an hierarchical linear model (HLM) model across 24 different study conditions. Variables manipulated in the analysis included, (a) number of Level-2 variables with missing data, (b) percentage of missing data, and (c) Level-2 sample size. Listwise deletion outperformed all other methods across all study conditions in the estimation of both fixed-effects and variance components. The model-based procedures evaluated, EM and MI, outperformed the other traditional MDTs, mean and group mean substitution, in the estimation of the variance components, outperforming mean substitution in the estimation of the fixed-effects as well. Group mean substitution performed well in the estimation of the fixed-effects, but poorly in the estimation of the variance components. Data in the current study were modeled as missing completely at random (MCAR). Further research is suggested to compare the performance of model-based versus traditional MDTs, specifically listwise deletion, when data are missing at random (MAR), a condition that is more likely to occur in practical research settings.
Date: August 2011
Creator: St. Clair, Suzanne W.
System: The UNT Digital Library
Parent Involvement and Science Achievement: A Latent Growth Curve Analysis (open access)

Parent Involvement and Science Achievement: A Latent Growth Curve Analysis

This study examined science achievement growth across elementary and middle school and parent school involvement using the Early Childhood Longitudinal Study – Kindergarten Class of 1998 – 1999 (ECLS-K). The ECLS-K is a nationally representative kindergarten cohort of students from public and private schools who attended full-day or half-day kindergarten class in 1998 – 1999. The present study’s sample (N = 8,070) was based on students that had a sampling weight available from the public-use data file. Students were assessed in science achievement at third, fifth, and eighth grades and parents of the students were surveyed at the same time points. Analyses using latent growth curve modeling with time invariant and varying covariates in an SEM framework revealed a positive relationship between science achievement and parent involvement at eighth grade. Furthermore, there were gender and racial/ethnic differences in parents’ school involvement as a predictor of science achievement. Findings indicated that students with lower initial science achievement scores had a faster rate of growth across time. The achievement gap between low and high achievers in earth, space and life sciences lessened from elementary to middle school. Parents’ involvement with school usually tapers off after elementary school, but due to parent school …
Date: August 2011
Creator: Johnson, Ursula Yvette
System: The UNT Digital Library
The Use Of Effect Size Estimates To Evaluate Covariate Selection, Group Separation, And Sensitivity To Hidden Bias In Propensity Score Matching. (open access)

The Use Of Effect Size Estimates To Evaluate Covariate Selection, Group Separation, And Sensitivity To Hidden Bias In Propensity Score Matching.

Covariate quality has been primarily theory driven in propensity score matching with a general adversity to the interpretation of group prediction. However, effect sizes are well supported in the literature and may help to inform the method. Specifically, I index can be used as a measure of effect size in logistic regression to evaluate group prediction. As such, simulation was used to create 35 conditions of I, initial bias and sample size to examine statistical differences in (a) post-matching bias reduction and (b) treatment effect sensitivity. The results of this study suggest these conditions do not explain statistical differences in percent bias reduction of treatment likelihood after matching. However, I and sample size do explain statistical differences in treatment effect sensitivity. Treatment effect sensitivity was lower when sample sizes and I increased. However, this relationship was mitigated within smaller sample sizes as I increased above I = .50.
Date: December 2011
Creator: Lane, Forrest C.
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