A brief, practical overview of "design effects" (DEFFs) is presented for users of the results of sample surveys. The overview is intended to help such users to determine how and when to use DEFFs and to compute them correctly. DEFFs are needed only for inferential statistics, not for descriptive statistics. When the selections for…

This study applies a procedure which yields estimates of true score change on the Scholastic Aptitude Test (SAT) adjusted for regression effects and student self-selection. It is shown that student self-selection in deciding to repeat an admissions test probably involves factors in addition to the measurement error attributable to variations in…

Formulas are derived for the bias in the maximum likelihood estimators (MLE) of the item parameters in the logistic item response model when examinee abilities are known. Numerical results are given for a typical verbal test for college admission. Most typically the bias of an MLE is about one-tenth of its standard error. It is very seldom more…

A possible method is developed for computing the asymptotic sampling variance-covariance matrix of joint maximum likelihood estimates in item response theory when both item parameters and abilities are unknown. For a set of artificial data, results are compared with empirical values and with the variance-covariance matrices found by the usual…

A procedure for estimating reliability in a factor analytic context, when reliability of the extracted factors is not an emphasis, is identified. The procedure is an extension of Dressel's work and might be applied in attitude measurement. It assesses how homogeneous the weighted original item responses are, when they are scored for pattern…

Investigated empirically through post mortem item-examinee sampling were the relative merits of two alternative procedures for allocating items to subtests in multiple matrix sampling and the feasibility of using the jackknife in approximating standard errors of estimate. The results indicate clearly that a partially balanced incomplete block…

Current usage and theory of standard error of measurement calls for one standard error of measurement figure to be used across all levels of scoring. The study revealed that scoring variance across scoring levels is not constant. As scoring ability increases scoring variance decreases. The assertion that low and high scoring subjects will…

The formulas which give the standard errors of factor loading estimates while available and computable are complicated, and our understanding of them is limited. A nontechnical description of their behavior under favorable and unfavorable conditions is given. Of particular interest is their behavior in the presence of singularities arising from…

In a manner similar to that used in the orthogonal case, formulas for the asymptotic standard errors of analytically rotated oblique factor loading estimates are obtained. This is done by finding expressions for the partial derivatives of an oblique rotation algorithm and using previously derived results for unrotated loadings. These include the…

Dependability of class means is analyzed by applying generalizability to a split-plot design with students nested within classes. Basic generalizability concepts are reviewed, and the derivation and interpretation of distinct generalizability concepts are discussed. Four generalizability coefficients are compared with each other and with the three…

Type I error rates and power were estimated for 10 tests of variance equality under various combinations of the following factors: similar and dissimilar distributional forms, equal and unequal means, and equal and unequal sample sizes. (TJH)

This paper summarizes much of the available information concerning the reliability and validity of the Tests of General Educational Development (GED Tests). The data suggest that the results are sufficiently reliable for continued use and that the validity evidence generally supports the intended uses of the tests. (Author/LMO)

Commonly used techniques for estimating the effect of data error on fund allocations are biased because they fail to account for numerous sources of data error and for misspecification of the allocation formula itself. Alternate methods for estimating the effects of data error are presented. (Author/BS)

Issues regarding tolerance and confidence intervals are discussed within the context of educational measurement, and conceptual distinctions are drawn between these two types of intervals. Points are raised about the advantages of tolerance intervals when the focus is on a particular observed score rather than a particular examinee. (Author/BW)