A jack knife is a pocket knife that is put to many tasks, because it's ready to hand. Often there could be a better tool for the job, such as a screwdriver, a scraper, or a can-opener, but these are not usually pocket items. In statistical terms, the expression implies making do with what's available. Another simile, of an extreme situation, is…

A simple statistical test procedure for assessing questionnaire response validity is proposed. The technique assesses the joint probability that frequently reported behaviors are not reported and infrequently reported behaviors are reported. (Author)

This article evaluated criticisms by Stevens and Aleamoni (1986) of an article by Gardner and Erdle (1984) on aggregation using either raw or standard scores. It was demonstrated that their criticisms were unfounded. (Author)

The development of a nonparametric K-sample test for equality of slopes using Puri's generalized L statistic is presented. The test is recommended when the assumptions underlying the parametric model are violated. This procedure replaces original data with either ranks (for data with heavy tails) or normal scores (for data with light tails).…

A computer program randomly sampled ordered pairs of scores from known populations that departed from bivariate normal form and calculated correlation coefficients from sample values. Hypotheses were tested (1) that population correlations are zero using the t statistic; and (2) that population correlations have non-zero values using the r to z…

Section pre-equating (SPE) equates a new test to an old test prior to the actual use of a new test by making extensive use of experimental sections of a testing instrument. SPE theory is extended to allow for practice effects on both the old and new tests. (Author/BS)

Rubin and Thayer recently presented equations to implement maximum likelihood estimation in factor analysis via the EM algorithm. It is argued here that the advantages of using the EM algorithm remain to be demonstrated. (Author/JKS)

The authors respond to a criticism of their earlier article concerning the use of the EM algorithm in maximum likelihood factor analysis. Also included are the comments made by the reviewers of this article. (JKS)

Demonstrates that some commonly used indices can be misleading in their quantification of reliability. The effects are most pronounced on gain or difference scores. Proposals are made to avoid sources of invalidity by using a procedure to assess reliability in terms of upper and lower limits for the true scores of each examinee. (Author/JDH)

This proposal attempts to follow in Allan Birnbaum's tradition by using Bayesian ideas to show that his mental test model possesses even broader applicability than previously realized. Birnbaum's two significant contributions to the theories of statistics and educational testing are: (1) the proof that the sufficiency and conditionality principles…

Two methods of constucting equal-interval scales for educational achievement are discussed: Thurstone's absolute scaling method and Item Response Theory. Alternative criteria for choosing a scale are contrasted. It is argued that clearer criteria are needed for judging the appropriateness and usefulness of alternative scaling procedures.…

Prior standardization of scores when an aggregate score is formed has been criticized. This article presents a demonstration of the effects of differential weighting of aggregate components that clarifies the need for prior standardization. The role of standardization in statistics and the use of aggregate scores in research are discussed.…

The reliability of simple difference scores is greater than, less than, or equal to that of residualized difference scores, depending on whether the correlation between pretest and posttest scores is greater than, less than, or equal to the ratio of the standard deviations of pretest and posttest scores. (Author)

The well-known problem of cumulating error probabilities is reconsidered from a general epistemological perspective, namely, the concepts of severity and of fairness of tests. It is shown that not only Type 1 but also Type 2 errors can cumulate. A new adjustment strategy is proposed and applied. (Author/JAZ)

Conjunctive item response models are introduced such that: (1) sufficient statistics for latent traits are not necessarily additive in item scores; (2) items are not necessarily locally independent; and (3) existing compensatory (additive) item response models including the binomial, Rasch, logistic, and general locally independent model are…