Quantum mechanics is often thought to be a difficult subject to understand, not only in the complexity of its mathematics but also in its conceptual foundation. In this paper we emphasize students' depictions of the uncertainty principle and wave-particle duality of quantum events, phenomena that could serve as a foundation in building an…

The focus article by Coburn and Turner (this issue) seeks to provide a comprehensive framework for understanding data use in the context of data-use interventions. This commentary focuses on what the authors see as a glaring omission in what is otherwise a valuable framework: the issue of "useful data." It is their contention that the usefulness…

Presents general principles for cleaning data sets. Suggests techniques: check for column shifts, data completeness, marginal frequencies, and selected cross-tabulations; examines a sample of cases. Gives strategies for preventing data processing errors. (SK)

Many do not consider the effect that missing data have on their survey results nor do they know how to handle missing data. This chapter offers strategies for handling item-missing data and provides a practical example of how these strategies may affect results. The chapter concludes with recommendations for preventing and dealing with missing…

Reviews problems involved in analyzing data on educational or training needs and details use of the proportionate reduction in error (PRE) approach (Hildebrand, et al., 1977), which predicts the probability that certain combinations of a joint distribution will occur, then tests to see how closely the prediction matches the observation. (MBR)

The conflict between immediacy and accuracy in data-gathering and analysis is discussed. The case of the Postsecondary Transcript Sample (PETS) of the National Longitudinal Study is used to illustrate the particulars of this conflict and their resolution on the side of accuracy. (Author/MLW)

Classical test theory, item response theory, and generalizability theory all treat the abilities to be measured as continuous variables, and the items of a test as independent probes of underlying continua. These models are well-suited to measuring the broad, diffuse traits of traditional differential psychology, but not for measuring the outcomes…

The seven cohort studies of the relation between prenatal and postnatal exposure to polychlorinated biphenyls (PCBs) to cognitive, neuropsychological and behavioral development have suggested that exposure to PCBs can cause persistent changes in cognitive functioning. D.V. Cicchetti, A.S. Kaufman, and S.S. Sparrow (this issue) apply six scientific…

This invited response to the paper by D.V. Cicchetti, A.S. Kaufman, and S.S. Sparrow (CKS), and the responses by the investigative teams of the studies criticized by them, addresses specific errors of logic and interpretation by CKS, and integrates comments made by the study investigators. CKS provide a flawed analysis of the literature on the…

This paper examines whether failure to control for family background, aptitude, high school quality, high school curriculum, and community characteristics leads to bias in estimates of the economic return resulting from postsecondary education. High school specific fixed effects were used to control for all observed and unobserved characteristics…