In this paper I present a class of discrete choice models for ordinal response variables based on a generalization of the stereotype model. The stereotype model can be derived and generalized as a random utility model for ordered alternatives. Random utility models can be specified to account for heteroscedastic and correlated utilities. In the…

The compatibility of the polychotomous Rasch model with dichotomization of the response continuum is discussed. It is argued that in the case of graded responses, the response categories presented to the subject are essentially an arbitrary polychotomization of the response continuum. (Author/LMO)

Statistical methods are presented to facilitate a more complete analysis of results obtained when a scaling model is applied to data from two or more groups. Various kinds of scaling models are considered here in the multiple-group context. (Author/LMO)

Glickman, Gray, and Morales (this issue) propose a statistical model for measuring the unobserved latency of stimulus-controlled processes. The model accounts for both speed and accuracy and does so by assuming that participants set an internal deadline. If a stimulus-controlled response is not produced by the deadline, the participant then…

The author shows that correlation studies can be affected by self-selection bias when questionnaire response is poor, contrary to the common supposition that only loss of degrees of freedom or precision result. Tests are suggested for the ensuing self-selection bias. (Author/LMO)

Van Breukelen (this issue) provides an approach to using both response time (RT) and accuracy for (1) measuring latent abilities of participants even when they may trade speed for accuracy, and for (2) providing insight into the psychological processes underlying task performance. In this commentary, I focus on the second of these aims and assess…

Human performance in cognitive testing and experimental psychology is expressed in terms of response speed and accuracy. Data analysis is often limited to either speed or accuracy, and/or to crude summary measures like mean response time (RT) or the percentage correct responses. This paper proposes the use of mixed regression for the psychometric…

Omitted items cannot properly be treated as wrong when estimating ability and item parameters. A convenient method for utilizing the information provided by omissions is presented. Theoretical and empirical justifications are presented for the estimates obtained by the new method. (Author)