Researchers are often inclined to test agreement or discrepancy hypotheses using difference scores. This commentary explains 2 mathematical-statistical principles underlying associations with difference scores and 2 conceptual-interpretation problems that make difference scores inappropriate for testing such hypotheses. The commentary provides…

The use of differences scores to assess agreement/disagreement has a long and contentious history. Laird (2020) notes, however, that developmentalists have been particularly resistant to discontinue the use of difference scores. One area of developmental science where difference scores are still in regular use is that of parental differential…

Preparing and supporting teachers to enact teaching practice that responds to diversity, challenges educational inequities, and promotes social justice is a pressing yet daunting and complex task. More research is needed to understand how and to what extent teacher education programs prepare and support teacher candidates to enhance the…

We are concerned with the hypothesis that two variables have a perfect disattenuated correlation, hence measure the same trait except for errors of measurement. This hypothesis is equivalent to saying, within the adopted model, that true scores of two psychological tests satisfy a linear relation. A statistical test of this hypothesis is derived…

When evaluating the utility of a psychological test for clinical decision making, both the psychometric properties of the test (i.e., the reliability and validity of the instrument) and the ambiguity of the language by which test results are interpreted or communicated need to be considered. Although each has been studied independently, to date…

Two psychological experiments--Anderson and Shanteau (1970), Berkowitz and LePage (1967)--are reanalyzed to present the problem of the relative importance of low Type 1 error probability and high power when answering a research question by testing several statistical hypotheses. (Author/PN)

Diagnostic testing confronts several challenges at once, among which are issues of test interpretation and immediate modification of the test itself in response to the interpretation. Several methods are available for administering and evaluating a test in real-time, towards optimizing the examiner's chances of isolating a persistent pattern of…

Implicit in the work of S. Huck and H. Sandler (1979) is the idea that the concept "rival hypotheses" refers to some kind of alternative explanation. Rather than being threats to internal validity, rival hypotheses, in their view, are interpretations that differ from those of the researcher. This paper broadens the idea to include any…

Too few researchers understand what statistical significance testing does and does not do, and consequently their results are misinterpreted. This Digest explains the concept of statistical significance testing and discusses the meaning of probabilities, the concept of statistical significance, arguments against significance testing,…

Factorial analyses differ from nonfactorial analyses in that in the former all possible hypotheses (all possible main effects and interaction effects) are tested regardless of their substantive interest to the researcher and their interpretability, while in the latter, only substantive and interpretable hypotheses are tested. This paper shows the…

A general method for identifying the separate components of the Rod-and-Frame Test consists of correlating theoretical patterns of scores with obtained test scores of single subjects. The correlation test calculates probability values from the test data. In this way, fit can be determined between theoretical pattern and test scores. (Author/BW)

A new method is proposed for a simultaneous factor analysis of dichotomous responses from several groups of individuals. The method makes it possible to compare factor loading pattern, factor variances and covariances, and factor means over groups. Generalized least squares is used as the estimation procedure. (Author/JKS)

A new procedure for determining the optimal number of interpretable factors to extract from a correlation matrix is introduced and compared to more conventional procedures. The new method evaluates the magnitude of the very simple structure index of goodness of fit for factor solutions of increasing rank. (Author/CTM)

Participation in test interpretation counseling by high school students, whether positively or neutrally oriented, has a greater effect on improving students' future achievement performance, than does the absence of counseling. (CK)