Questionnaires that include items eliciting count responses are becoming increasingly common in psychology. This study proposes methodological techniques to overcome some of the challenges associated with analyzing multivariate item response data that exhibit zero inflation, maximum inflation, and heaping at preferred digits. The modeling…

Missing data is endemic in much educational research. However, practices such as step-wise regression common in the educational research literature have been shown to be dangerous when significant data are missing, and multiple imputation (MI) is generally recommended by statisticians. In this paper, we provide a review of these advances and their…

In a series of publications, the author and his colleagues have obtained scores from students in higher education on different questionnaires, and they have described the relationships among these scores using the statistic known as Wilks' [lambda]. Burt (2005) has criticized that the use of this measure is inappropriate, arguing (1) that the…

Establishing stability, defined as observing minimal measurement error in a test-retest assessment, is vital to validating psychometric tools. Correlational methods, such as Pearson product-moment, intraclass, and kappa are tests of association or consistency, whereas stability or reproducibility (regarded here as synonymous) assesses the…

This report shows that there are many ways to confirm the accuracy, reliability, and validity of student self-reports. Examples from higher education and from public opinion polls and general surveys demonstrate some of the common sources of measurement errors and errors of substance. Part 1 of the report summarizes a few highlights from the…

This study explores the utility of analytic scoring for the TOEFL® Academic Speaking Test (TAST) in providing useful and reliable diagnostic information in three aspects of candidates' performance: delivery, language use, and topic development. G studies were used to investigate the dependability of the analytic scores, the distinctness of the…