Incidence sampling is a parsimonious method whereby a large number of examinees can be measured on many variables (such as test items) to assess group characteristics. Parameters used to describe an incidence sample are estimated using the theory of generalized symmetric means and generalizability theory. (Author/JKS)

This paper elaborates on the work of Cardinet, and others, by clarifying some points regarding calculations, specifically with reference to existing computer programs, and by presenting illustrative examples of the calculation and interpretation of several generalizability coefficients from a complex six-facet (factor) design. (Author/RL)

Livingston's work is a careful analysis of what occurs when one pools two populations with different means, but similar variances and reliability coefficients. However, his work fails to advance reliability theory for the special case of criterion-referenced testing. See ED 042 802 for Livingston's paper. (MS)

Using data from a National Child Development Study (NCDS) in Great Britain, the applications of instrumental variable methods and structural equation models to estimating instrumental variables are presented. A subset of the longitudinal educational and home background data on children born in England, Wales and Scotland in a March week of 1958 is…

Textbook calculations of statistical power or sample size follow from formulas that assume that the variables under consideration are measured without error. However, in the real world of behavioral research, errors of measurement cannot be neglected. The determination of sample size is discussed, and an example illustrates blocking strategy.…

Most training programs in education and psychology focus on classical test theory techniques for assessing score dependability. This paper discusses generalizability theory and explores its concepts using a small heuristic data set. Generalizability theory subsumes and extends classical test score theory. It is able to estimate the magnitude of…

Believing that examinee-by-item interaction should be conceptualized as true score variability rather than as a result of errors of measurement, Lu proposed a modification of Hoyt's analysis of variance reliability procedure. Via a computer simulation study, it is shown that Lu's approach does not separate interaction from error. (Author/RL)

This study is an attempt at a cohesive characterization of the concept of essay reliability. As such, it takes as a basic premise that previous and current practices in reporting reliability estimates for essay tests have certain shortcomings. The study provides an analysis of these shortcomings--partly to encourage a fuller understanding of the…

Eight different methods are reviewed for determining whether two or more tests are equivalent measures. These methods vary in restrictiveness from the Wilks-Votaw test of compound symmetry (which requires that all means, variances, and covariances are equal), to Joreskog's theory of congeneric tests (which requires only that the tests are measures…

Although the standard-setting method of W. H. Angoff (1971) has broad-based support in the research literature, inconsistencies in the resulting standards do occur. Sources of these inconsistencies are examined in a study of judges, competencies (items), rounds (replications), and the interactions among them. A modified Angoff approach was used to…

Using the basic principles of generalizability theory, a psychometric model for domain-referenced interpretations is proposed, discussed, and illustrated. This approach, assuming an analysis of variance or linear model, is applicable to numerous data collection designs, including the traditional persons-crossed-with-items design, which is treated…

A nontechnical approach to statistics is presented. The examples and illustrations have been drawn from the classroom and the needs of teachers who wish to measure and understand the progress of their pupils. The areas covered include the following topics: (1) different forms of average, middle value, dispersion of data around the average, and the…

Data from the Second International Mathematics Study for 3,724 eighth graders are used to demonstrate the potential of multilevel factor analysis (MFA) methodology. Issues related to between-class and within-class decomposition of achievement variance and the change in this decomposition over the course of the eighth grade are revealed through…