No description available.

The purpose of this research was to investigate the relation between measurement bias at the item level (differential item functioning, dif) and predictive bias at the test score level. Dif was defined as a difference in the probability of getting a test item correct for examinees with the same ability but from different subgroups. Predictive bias was defined as a difference in subgroup regression intercepts and/or slopes in predicting a criterion. Data were simulated by computer. Two hypothetical subgroups (a reference group and a focal group) were used. The predictor was a composite score on a dimensionally complex test with 60 items. Sample size (35, 70, and 105 per group), validity coefficient (.3 or .5), and the mean difference on the predictor (0, .33, .66, and 1 standard deviation, sd) and the criterion (0 and .35 sd) were manipulated. The percentage of items showing dif (0%, 15%, and 30%) and the effect size of dif (small = .3, medium = .6, and large = .9) were also manipulated. Each of the 432 conditions in the 3 x 2 x 4 x 2 x 3 x 3 design was replicated 500 times. For each replication, a predictive bias analysis was conducted, and the detection of predictive bias against each subgroup was the dependent variable. The percentage of dif and the effect size of dif were hypothesized to influence the detection of predictive bias; hypotheses were also advanced about the influence of sample size and mean subgroup differences on the predictor and criterion. Results indicated that dif was not related to the probability of detecting predictive bias against any subgroup. Results were inconsistent with the notion that measurement bias and predictive bias are mutually supportive, i.e., the presence (or absence) of one type of bias is evidence in support of the presence (or absence) of the other type of bias. Sample size and mean differences on the predictor/criterion had direct and indirect effects on the probability of detecting predictive bias against both reference and focal groups. Implications for future research are discussed.

The effectiveness of multidimensional scaling (MDS) techniques in recovering the underlying dimensionality of dichotomously-scored data was examined for unidimensional and multidimensional data. Thirty-three data sets of varying numbers of dimensions with differing patterns of item discrimination were generated using a multidimensional latent trait model in a Monte Carlo simulation study. Margin-sensitive measures (agreement, phi, and kappa) and margin-free measures (Φ/ Φ(max), Yule's Q, and the tetrachoric correlation) were used as measures of similarity and the resulting matrices were scaled in one through five dimensions. Values of the stress coefficient, S₁, S₁ by dimensionality plots, and plot configurations were examined to determine the dimensionality of the item set. Principal components analyses (PCAs) of phi and tetrachoric matrices were carried out as a basis for comparison. In addition, MDS and PCA were used to examine a data set comprised of items obtained from the routing tests of the Head Start Measures Battery. Two effects of item discrimination on MDS results were especially noteworthy. First, factors tended to be located equally distant from each other in the MDS space. Items were located closest to the factor for which the primary factor loading occurred. Second, as item discrimination decreased, items tended to be more widely dispersed from their appropriate locations in space. Extra dimensions in the MDS representational space were required for margin-sensitive coefficients to accommodate difficulty effects. Margin-free coefficients generally eliminated difficulty-related dimensions, although occasional problems were noted with the tetrachoric correlation. Analysis of the HSMB revealed that the data were primarily unidimensional, although specific effects due to each subtest were clearly present in the analysis. MDS was found to be a useful technique and its use in conjunction with PCA or factor analysis is recommended.

The present study was a systematic investigation of hierarchical skill sequences in the beginning reading domain. The hierarchies included skills from the traditional approach to reading which reflect bottom-up processing and skills from the conceptual area of print awareness which reflect top-down processing. Researchers supporting the bottom-up approach view reading as a process in which the child extracts information from the text to gain knowledge of the print. The bottom-up processes examined were in the areas of letter recognition and letter naming, and identification of letter sounds and phonemes. The top-down processing approach views reading as a task in which the child brings his/her past experiences and knowledge about the world to gain information about print. The top-down processes examined were in the areas of print identification, inferring a word in context, and print directionality rules. Hierarchical skill sequences were developed within each of the specific areas reflecting the top-down and bottom-up processing theories. Items were developed to reflect the skill sequences based on the cognitive processes that are necessary for correct performance. This involved varying the task demands imposing various requirements of cognitive processing. The data were from 13,189 Head Start children ranging from 3 to 6 years of age. Latent trait models were constructed to reflect the viii ix hypothesized skill sequences by allowing the aj (discrimination) and bj (difficulty) parameters to be free to vary or by constraining them to be equal to other parameters. To arrive at a preferred model, each latent trait model that represented a hypothesized skill sequence was statistically compared against alternative latent trait models. The results from the present investigation supported the hierarchical skill sequences reflecting skills within the traditional area of reading. However, some of the skill sequences from the conceptual area of print awareness were not clearly supported. While the results provide a deeper understanding of beginning reading skill sequences reflecting top-down and bottom-up processing theories, future research is needed to delineate the specific skills which promote later reading ability once the child is in formal reading instruction.

Thesis (Ph. D.)--University of Texas at Austin, 2003. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (Ph. D.)--University of Missouri-Columbia, 2008. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on July 28, 2009 Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: Barbara G. Dodd. Vita. Includes bibliographical references.

Thesis (Ph. D.)--Brigham Young University. Dept. of Instructional Psychology and Technology, 2004. / Includes bibliographical references (p. 103-106).

No description available.

Utilizing Item Response Theory (IRT) methodologies, the Armed Services Vocational Aptitude Battery (ASVAB) was examined for differential item functioning (DIF) on the basis of crossed gender and ethnicity variables. Both the Mantel-Haenszel procedure and an IRT area-based technique were utilized to assess the degree of uniform and non-uniform DIF in a sample of ASVAB takers. The analysis was performed such that each subgroup of interest functioned as the focal group to be compared to the male reference group. This type of DIF analysis allowed for comparisons within ethnic group, within gender group, as well as crossed ethnic/gender group. The groups analyzed were: White, Black, and Hispanic males, and White and Black females. It was hypothesized that DIF would be found, at the scale level, on several of the ASVAB sub-tests as a result of unintended latent trait demands of items. In particular, those tests comprised of items requiring specialized jargon, visuospatial ability, or advanced English vocabulary are anticipated to show bias toward white males and/or white females. Findings were mixed. At the item level, DIF fluctuated greatly. Numerous instances of DIF favoring the reference as well as the focal group were found. At the scale level, inconsistencies existed across the forms and versions. Tests varied in their tendency to be biased against the focal group of interest and at times, performed contrary to expectations. / Master of Science