A model of test item dependency is presented and used to illustrate the effect that violations of local independence have on the behavior of item characteristic curves. The dependency model is flexible enough to simulate the interaction of a number of factors including item difficulty and item discrimination, varying degrees of item dependence,…

For the purpose of obtaining data to use in test development, multiple matrix sampling plans were compared to examinee sampling plans. Data were simulated for examinees, sampled from a population with a normal distribution of ability, responding to items selected from an item universe. (Author/LMO)

Five sets of paired comparison judgments were made concerning test item difficulty, in order to identify the most probable source of intrasensitivity in the data. The paired comparisons method was useful in providing information about sensitivity to stimulus differences, but less useful for assessing dimensionality of judgment criteria.…

Whether or not subjects can simulate mental retardation, a consideration that has implications in criminal cases, was studied using 21 adult Caucasian males between 20 and 30 years of age, largely comprised of students and staff employees of the University of New Mexico. Subjects were asked to give genuine and simulated responses to two major test…

Factor analysis is the traditional method for studying the dimensionality of test data. However, under common conditions, the factor analysis of tetrachoric correlations does not recover the underlying structure of dichotomous data. The purpose of this paper is to demonstrate that the factor analyses of tetrachoric correlations is unlikely to…

In this paper a Bayesian procedure is developed for the simultaneous estimation of the reading ability and difficulty parameters which are assumed to be factors in reading errors by the multiplicative Poisson Model. According to several criteria, the Bayesian estimates are better than comparable maximum likelihood estimates. (Author/JAZ)

The study compares three methods for establishing cut-off scores that effect a compromise between absolute cut-offs based on item difficulty and relative cut-offs based on expected passing rates. Each method coordinates these two types of information differently. The Beuk method obtains judges' estimates of an absolute cut-off and an expected…

This paper deals with test fairness regarding a test consisting of two parts: (1) a "common" section, taken by all students; and (2) a "variable" section, in which some students may answer a different set of questions from other students. For example, a test taken by several thousand students each year contains a common multiple-choice portion and…

The TESTFACT computer program and full-information factor analysis of test items were used in a computer simulation conducted to correct for the guessing effect. Full-information factor analysis also corrects for omitted items. The present version of TESTFACT handles up to five factors and 150 items. A preliminary smoothing of the tetrachoric…

Growth of administrative components in 43 K-12 public school districts in the Saint Louis metropolitan area is reported for 1968-76. Increases in absolute numbers and ratios of administrators to teachers occurred in school districts with increasing as well as declining enrollments. Statistical analysis of public records and interviews with…

Problems and procedures in assessing and obtaining fit of data to the Rasch model are treated and assumptions embodied in the Rasch model are made explicit. It is concluded that statistical tests are needed which are sensitive to deviations so that more than one item parameter would be needed for each item, and more than one person parameter would…

On the basis of past research efforts to improve multiple-choice test information through differential weighting of responses to wrong answers (distractors), two statistical indices are developed. Each describes the properties of response distributions across the options of an item. Jaspen's polyserial generalization of the biserial correlation…

Based on the standard setting procedures or the American Board of Preventive Medicine for their Core Test, this article describes how Rasch measurement can facilitate using test content judgments in setting a standard. Rasch measurement can then be used to evaluate and improve the precision of the standard and to hold it constant across time.…

Although perfectly scalable items rarely occur in practice, Guttman's concept of a scale has proved to be valuable to the development of measurement theory. If the score distribution is uniform and there is an equal number of items at each difficulty level, both the elements and the eigenvalues of the Pearson correlation matrix of dichotomous…

A primary goal of this study was to determine the extent to which item difficulty was related to item position and, if a significant relationship was found, to suggest adjustments to predicted item difficulty that reflect differences in item position. Item response data from the Medical College Admission Test (MCAT) were analyzed. A data set was…