This study investigated the impact of task directions on the mathematical performance of high school students from six classes. Students analyzed data regarding school dropout by answering six short-answer questions and writing a letter discussing the trends and their predictions about school dropout. Tasks were scored using two methods: (1) trait…

Fit statistics provide a direct measure of assessment accuracy by analyzing the fit of measurement models to an individual's (or group's) response pattern. Students that lose interest during the assessment, for example, will miss exercises that are within their abilities. Such students will respond correctly to some more difficult items and…

This paper reports a method for assessing the adequacy of existing item banks for computer adaptive testing. The method takes into account content specifications, test length, and stopping rules, and can be used to determine if an existing item bank is adequate to administer a computer adaptive test efficiently across differing levels of examinee…

A method is presented for the simultaneous analysis of differential item functioning (DIF) in multi-factor situations. The method is unique in that it combines item response theory (IRT) and analysis of variance (ANOVA), takes a simultaneous approach to multifactor DIF analysis, and is capable of capturing interaction and controlling for possible…

The purposes of this study were to introduce the iterative purification procedure and to compare this with the two-step purification procedure, to compare false positive error rates and the power of five observed score approaches and to identify factors affecting power and false positive rates in each method. This study used 2,400 data sets that…

Accuracy of item parameter estimates is a critical concern for any application of item response theory (IRT). However, the necessary sample sizes are often difficult to obtain in practice, particularly for the more complex models. A promising avenue of research concerns modified item response models. This study both replicates and improves on an…

Several person-fit statistics have been proposed to detect item score patterns that do not fit an item response theory model. To classify response patterns as not fitting a model, a distribution of a person-fit statistic is needed. The null distributions of several fit statistics have been investigated using conventionally administered tests, but…

This report examines both the substantiveness and statistical significance of differences between mean American College Testing (ACT) Program assessment scale scores. The first part of the report describes the development and results of a method for interpreting the substantiveness of mean differences in terms of test items correctly answered. For…

Large gains in scores have been observed over the first years of the Kentucky Instructional Results Information System (KIRIS) program. The extent to which these gains in scores indicate that student learning improved was evaluated. Previous studies have suggested that KIRIS score gains might be appreciably inflated, something that might result…

This study investigated the effect of writing task topic on learner performance in a second-language writing test, in this case the Michigan English Language Assessment Battery designed to test proficiency in English as a Second Language. The 64 topics or "prompts" used in the test (offered as pairs of options) were categorized according…

Modified Parallel Analysis (MPA) is a heuristic method for assessing "approximate unidimensionality" of item pools. It compares the second eigenvalue of the observed correlation matrix with the corresponding eigenvalue extracted from a "parallel" matrix generated by a unidimensional and locally independent model. Revised…

The first purpose of this study was to investigate the stability of two essential dimensionality measures across 10 random samples within a particular assessment item (AT1) selection. Other purposes were to investigate the discrepancy of the essential unidimensionality estimates for a test across different AT1 selections and sample sizes and to…

A didactic example is provided, using a Monte Carlo method, of how differential item functioning (DIF) can be eliminated (and thus better understood) when the complete latent space is used. The main source of DIF is that the matching single criterion used in some DIF procedures, Mantel Haenszel or Simultaneous Item Bias (SIBTEST), does not account…

The Iowa Test of Educational Development (ITED), a test of general abilities given to high school students, is intended as a tool for teachers and administrators to measure the progress of their students and plan accordingly; it also purports to assess the use by students of critical and evaluative abilities. Because such tests as the ITED carry…

Performance in assessing the unidimensionality of tests was examined for four methods: (1) W. F. Stout's procedure (1987); (2) the approach of P. W. Holland and P. R. Rosenbaum (1986); (3) linear factor analysis; and (4) non-linear factor analysis. Each method was examined and compared with the others using simulated and real test data. Seven data…