Null hypothesis testing (NHT) is the most commonly used tool in empirical psychological research even though it has several known limitations. It is argued that since the hypotheses evaluated with NHT do not reflect the research-question or theory of the researchers, conclusions from NHT must be formulated with great modesty, that is, they cannot…

Most psychotherapy research uses a one-with-many design, in which each therapist (the one) treats multiple clients (the many), which raises the challenge of nonindependent data. We present a statistical model for analyzing data from studies that use a one-with-many design. This model addresses the problems associated with nonindependence and can…

The current study proposes a new procedure for separately estimating slope change and level change between two adjacent phases in single-case designs. The procedure eliminates baseline trend from the whole data series before assessing treatment effectiveness. The steps necessary to obtain the estimates are presented in detail, explained, and…

Among the many methods available for modeling intraindividual time series, differential equation modeling has several advantages that make it promising for applications to psychological data. One interesting differential equation model is that of the damped linear oscillator (DLO), which can be used to model variables that have a tendency to…

The Candecomp/Parafac (CP) method decomposes a three-way array into a prespecified number R of rank-1 arrays, by minimizing the sum of squares of the residual array. The practical use of CP is sometimes complicated by the occurrence of so-called degenerate sequences of solutions, in which several rank-1 arrays become highly correlated in all three…

The purpose of this research was to examine the effects of missing data on person-model fit and person trait estimation in tests with dichotomous items. Under the missing-completely-at-random framework, four missing data treatment techniques were investigated including pairwise deletion, coding missing responses as incorrect, hotdeck imputation,…

A model of the response process based on signal-detection theory (Tanner & Swets, 1954) was used to analyse PI effects in three different tests of short-term memory. (Editor)

The purpose of this study was to establish a theoretical framework for Stevens' empirically derived power law. Three models were proposed to explain the power law. (Editor)

This article reports the results of an experiment addressing extrapolation in function learning, in particular the issue of whether participants can extrapolate in a nonmonotonic manner. Existing models of function learning, including the extrapolation association model of function learning (EXAM; E. L. DeLosh, J. R. Busemeyer, & M. A. McDaniel,…

A model of similarity-based retrieval is presented that attempts to capture these seemingly contradictory psychological phenomena: (1) structural commonalities are weighed more heavily than surface commonalities in soundness or similarity judgments (when both members are present); (2) superficial similarity is more important in retrieval from…

This paper attempted to resolve major methodological and design inadequacies associated with encounter, T-, and sensitivity groups. In addition, it highlighted some issues that have not been sufficiently considered previously. (Author/RK)

Three models are proposed to describe the strategy applied by a subject when he is confronted with two successive time intervals and is required to deal with some relation between them, for example, by telling which was the longer by adjusting the second to match the first. (Author)

A theoretical model for estimating the effects of age and incentive on children's performance in probability learning is introduced. Novel predictions of the model about the effects of combinations of age and incentive were tested and confirmed. (Editor/RK)

A confluence model is developed that explains the effects of birth order and family size on intelligence. (Editor)

This study attempts to discriminate between 2 theories about strategies Ss use when trying to remember a linear ordering. (Editor)