Browsing by Author "Linn, Robert L."
Now showing 1 - 8 of 8
Results Per Page
Sort Options
Item A generalized logistic item response model parameterizing test score inappropriateness(1987) Strandmark, Nancy L.; Linn, Robert L.The person response curve has been suggested as a possible model for test score inappropriateness (Lumsden, 1977, 1978; Weiss, 1973). The two-parameter person response curve proposed by Lumsden includes a person slope parameter but abandons the notion of differential item relatedness to the underlying trait. As an alternative, a generalized logistic model is considered that includes all item parameters of the three-parameter logistic model (Birnbaum, 1968). In addition to the usual person location parameter, the model has extra person parameters representing two possible characterizations of test score inappropriateness: a slope parameter indicating the degree to which a person responds differently to items of varying difficulty, and an asymptote parameter measuring a person’s proclivity to engage in effective guessing or to omit items in the presence of partial information. To assess the model’s feasibility, statistical comparisons were made between parameter estimates from data simulated according to the model and the original simulation parameters. The results seem encouraging, but additional empirical study is needed before firm conclusions can be drawn.Item Group differentiated prediction(1984) Linn, Robert L.; Hastings, C. NicholasStudies of predictive bias have frequently shown that a prediction equation based on majority group members tends to overpredict the criterion performance of minority group members. Two statistical artifacts that may cause the overprediction finding are reviewed and evaluated using data for black and white students at 30 law schools. It is shown that (1) the degree of overprediction decreases as the predictive accuracy for white students increases, and (2) that overprediction can be caused by the effects of selection on variables not included in the regression model. Use of Heckman’s (1979) procedure to adjust the estimates of the regression parameters was found to essentially eliminate overprediction.Item Indices for detecting unusual patterns: Links between two general approaches and potential applications(1983) Tatsuoka, Kikumi K.; Linn, Robert L.Two distinct approaches, one based on item response theory and the other based on observed item responses and standard summary statistics, have been proposed to identify unusual response patterns of responses to test items. A link between these two approaches is provided by showing certain correspondences between Sato’s S-P curve theory and item response theory. This link makes possible several extensions of Sato’s caution index that take advantage of the results of item response theory. Several such indices are introduced and their use illustrated by application to a set of achievement test data. Two of the newly introduced extended indices were found to be very effective for purposes of identifying persons who consistently use an erroneous rule in attempting to solve signed-number arithmetic problems. The potential importance of this result is briefly discussed.Item Issues of validity for criterion-referenced measures(1980) Linn, Robert L.It has sometimes been assumed that validity of criterion-referenced tests is guaranteed by the definition of the domain and the process used to generate items. These are important considerations for content validity. It is argued that the proper focus for content validity is on the items of a test rather than on examinee responses to those items. Content validity is important for criterion-referenced measures, but it is not sufficient. This claim is discussed and the case is made that interpretations and uses of criterion-referenced tests require support of other kinds of evidence and logical analysis. The inferences that are made should dictate the kinds of evidence and logical arguments that are needed to support claims of validity. Illustrations of aspects of the validation process are provided in two concrete examples.Item Item bias in a test of reading comprehension(1981) Linn, Robert L.; Levine, Michael V.; Hastings, C. Nicholas; Wardrop, James L.The possibility that certain features of items on a reading comprehension test may lead to biased estimates of the reading achievement of particular subgroups of students was investigated. Eight nonoverlapping subgroups of students were defined by the combinations of three factors: student grade level (fifth or sixth), income level of the neighborhood in which the school was located (low and middle or above), and race of the student (black or white). Estimates of student ability and item parameters were obtained separately for each of the eight subgroups using the three-parameter logistic model. Bias indices were computed based on differences in item characteristic curves for pairs of subgroups. A criterion for labeling an item as biased was developed using the distribution of bias indices for subgroups of the same race that differed only in income level or grade level. Using this criterion, three items were consistently identified as biased in four independent comparisons of subgroups of black and white students. Comparisons of content and format characteristics of items that were identified as biased with those that were not, or between items biased in different directions, did not lead to the identification of any systematic content differences. The study did provide strong support for the viability of the estimation procedure; item characteristics, estimated with samples from different populations were very similar. Some suggestions for improvements in methodology are offered.Item The Rasch model, objective measurement, equating, and robustness(1979) Slinde, Jeffrey A.; Linn, Robert L.This study investigated the adequacy of the Rasch model in providing objective measurement when equating existing standardized reading achievement tests with groups of examinees not widely separated in ability. To provide the context for the assessment of objectivity with the Rasch model, information relevant to several assumptions of the model was provided. An anchor test procedure was used to equate the various pairs of existing achievement tests. Despite the considerable lack of fit of the data to the model found for all tests used, the Rasch difficulty estimates were reasonably invariant for replications with random samples as well as samples that differed in ability by one grade level. Furthermore, with the exception of the data for one test pair and one grade level, the Rasch model using the anchor test procedure provided a reasonably satisfactory means of equating three test pairs on the log ability scale for the examinees at two grade levels.Item Research Reports, 1975, 1-6(University of Minnesota, Department of Psychology, 1975) Weiss, David J.; Larkin, Kevin C.; Vale, David C.; McBride, James R.; Betz, Nancy; Sympson, James B.; Linn, Robert L.; Bock, Darrell R.Item Validity generalization and situational specificity: An analysis of the prediction of first-year grades in law school(1981) Linn, Robert L.; Harnisch, Delwyn L.; Dunbar, Stephen B.Results from 726 validity studies were analyzed to determine the degree of validity generalization of the Law School Admission Test for predicting first-year grades in law school. Four validity generalization procedures were used and their results compared. As much as 70% of the variance in observed validity coefficients could be accounted for by differences in the within-study variability of LSAT scores, simple sampling error, and between-study differences in criterion reliability. The 90% credibility value for the true validities was estimated to be .45, and the average true validity was estimated to be .54. Despite the substantial degree of validity generalization, law school and the year the study was conducted explained significant portions of the residual variance in validities. Thus, some degree of situational specificity of validity remained.