Four general criteria are proposed for the choice of a metrical solution for a causal effect: (1) compatibility with the effect; (2) ease of communication; (3) lack of measurement error bias; and (4) stability across subjects and situations. These criteria are illustrated for randomized and nonrandomized designs. (SLD)

The distinction between two models of reliability is clarified. Reliability may be conceived of and estimated from a true score model or from the perspective of sampling precision. Basic models are developed and illustrated for each approach using data from the author's work on measuring organizational climate. (SLD)

Some of the threats to internal validity that arise when evaluating the impact of water conservation programs during a drought are illustrated. These include differential response to the drought, self-selection bias, and measurement error. How to deal with these problems when high-quality disaggregate data are available is discussed. (SLD)

Effects of response guided experimentation in applied behavior analysis on Type I error rates are explored. Data from T. A. Matyas and K. M. Greenwood (1990) suggest that, when visual inspection is combined with response guided experimentation, Type I error rates can be as high as 25%. (SLD)

The study calculated indices of interjudge reliability and interjudge and intrajudge agreement on ratings made by 15 experienced speech clinicians on 5 deviant speech dimensions of 15 speakers with ataxic dysarthria and a wide range of speech intelligibility. Judges were reliable in tracking imprecise consonants, excess and equal stress, and harsh…

Nonlinear relationships and latent variable assumptions can lead to serious specification errors in structural models. A quadratic relationship, described by a linear structural model with a latent variable, is shown to have less predictive validity than a simple manifest variable regression model. Advocates the use of simpler preliminary…

A reparameterization is formulated that yields estimates of scale-invariant parameters in recursive path models with latent variables, and (asymptotically) correct standard errors, without the use of constrained optimization. The method is based on the logical structure of the reticular action model. (Author)

The relationship between self- and peer report on the Coping Inventory for Stressful Situations (CISS) (N. Endler and J. Parker, 1990) was studied with 163 pairs of friends (college students). Positive but modest correlations were found between peer and self-report for three types of coping. Findings that attenuate these correlations are…

Explores effects of ignoring one or more levels of variation in hierarchical linear regression analysis, using a model with four hierarchical levels. Ignoring the top or intermediate levels influences fixed coefficients, variance components, and their corresponding standard error and can lead to different research conclusions. (Contains 16…

A program for obtaining ability estimates and their standard errors under a variety of psychometric models is documented. The general models considered are (1) classical test theory; (2) item factor analysis for continuous censored responses; and (3) unidimensional and multidimensional item response theory graded response models. (SLD)

This activity makes students a part of an investigation that determines the frequency of a particular plant variety in a simulated population. Provides an opportunity for students to observe the inherent variability of estimates, observe the relationship between sample size and sampling error, and consider aspects of research design. (Author/SAH)

The calculations of D. Schretlen, R. H. B. Benedict, and J. H. Bobholz for the reliabilities of a short form of the Wechsler Adult Intelligence Scale--Revised (WAIS-R) (1994) consistently overestimated the values. More accurate values are provided for the WAIS--R and a seven-subtest short form. (SLD)

Because of the requirement of reporting effect sizes and in the interest of measurement of change within the item response theory framework, their combination becomes a new issue. In the present study, repeated measures are decomposed as an initial ability and one or more modifiabilities (gain score) using a multidimensional Rasch model. The…

This article considers the implications for other noncentrality parameter-based statistics from Steiger's (1998) multiple sample adjustment to the root mean square error of approximation (RMSEA) measure. When a structural equation model is fitted simultaneously in more than 1 sample, it is shown that the calculation of the noncentrality parameter…

The primary purpose of this article was to offer a methodological critique in support of arguments that racial categories should be replaced as explanatory constructs in psychological research and theory. To accomplish this goal, the authors (a) summarized arguments for why racial categories should be replaced; (b) used principles of the…