The Regression-Based Discrepancy Definition of Learning Disability

The regression-based discrepancy definition of learning disabilities has been suggested by Rutter and Yule as an improvement of the well-known and much criticized achievement–intelligence discrepancy definition, whereby the examinee’s predicted reading attainment is substituted for the intelligence score in the discrepancy expression. Even though the regression-based discrepancy definition has been with us for more than 30 years, critical examination of this approach is scarce. This article fills this lacuna by examining the implications of two variables in the model on the diagnosis of learning disabilities: (a) the effect of predictive validity on the proportion of examinees identified as learning disabled, and (b) the effect of the predictor’s identity on the identity of the examinees diagnosed with learning disabilities. Implications of these effects concerning the validity of the regression-based discrepancy model and of the results of its implementation are discussed. </jats:p

Nonparametric Analysis of Longitudinal Binary Data: An Application to the Intergroup Prisoner's Dilemma Game

The intergroup prisoner's dilemma game was suggested by Bornstein (1992, Journal of Personality and Social Psychology. 7, 597–606) for modelling intergroup conflicts over continuous public goods. We analyse data of an experiment in which the game was played for 150 rounds, under three matching conditions. The objective is to study differences in the investment patterns of players in the different groups. A repeated measures analysis was conducted by Goren and Bornstein (1999, Games and Human Behaviour: Essays in Honor of Amnon Rapoport, pp. 299–314), involving data aggregation and strong distributional assumptions. Here we introduce a nonparametric approach based on permutation tests. Two new measures, the cumulative investment and the normalised cumulative investment, provide additional insight into the differences between groups. The proposed tests are based on the area under the investment curves. They identify an overall difference between the groups as well as pairwise differences. A simultaneous confidence band for the mean difference curve is used to detect the games which account for any pairwise difference. Copyright Kluwer Academic Publishers 2003randomisation tests, multiple comparisons, displacement approach, conflict resolution problems,

The Extra-Examination Time Granting Policy

Differential granting of extra-examination time (EET) is commonly based on learning disabilities (LD) status: EET is granted to LD examinees and is denied to nondisabled examinees. We argue that LD serves as a proxy for the extent to which time limitation affects the examinee’s test score ( e). Hence, the validity of the LD-based EET granting policy depends on how well LD status serves as a proxy for e. Reanalysis of 11 comparative experimental studies of the effect of EET shows that LD status is a poor proxy for e. The proportion of nondisabled examinees who benefit from EET roughly equals the corresponding proportion among LD students. Implications of these results for the validity and fairness of this policy are discussed. </jats:p