This study investigates parameter estimation under the simple linear regression model for situations in which the underlying assumptions of ordinary least squares estimation are untenable. Classical nonparametric estimation methods are directly compared against some robust estimation methods for conditions in which varying degrees of outliers are…

In previous works, D. J. Woodruff derived expressions for three different conditional test score variances: (1) the conditional standard error of prediction (CSEP); (2) the conditional standard error of measurement in prediction (CSEMP); and (3) the conditional standard error of estimation (CSEE). He also presented step-up formulas that require…

This paper compares various methods of smoothed equipercentile equating and linear equating in the random groups equating design. Three presmoothing methods (based on the beta binomial model, four-parameter beta binomial model and a log-linear model) are compared to postsmoothing using cubic splines, linear equating and unsmoothed equipercentile…

A method is presented for the simultaneous analysis of differential item functioning (DIF) in multi-factor situations. The method is unique in that it combines item response theory (IRT) and analysis of variance (ANOVA), takes a simultaneous approach to multifactor DIF analysis, and is capable of capturing interaction and controlling for possible…

The purposes of this study were to introduce the iterative purification procedure and to compare this with the two-step purification procedure, to compare false positive error rates and the power of five observed score approaches and to identify factors affecting power and false positive rates in each method. This study used 2,400 data sets that…

Accuracy of item parameter estimates is a critical concern for any application of item response theory (IRT). However, the necessary sample sizes are often difficult to obtain in practice, particularly for the more complex models. A promising avenue of research concerns modified item response models. This study both replicates and improves on an…

A two-level regression model is imposed on the ability parameters in an item response theory (IRT) model. The advantage of using latent rather than observed scores as dependent variables of a multilevel model is that this offers the possibility of separating the influence of item difficulty and ability level and modeling response variation and…

The Pearson product moment (P.M.) correlation ("r") and four of its most widely used variations--the phi, the rho, the biserial, and the point-biserial coefficients--are reviewed. Using small data sets between one and nine, the conditions under which the various forms are restricted in power and robustness are explored. Seven sample data…

The development of information for adjustment of the 1990 decennial census conducted by the U.S. Department of Commerce is discussed. Policy guidelines for the adjustment decision, which have been the subject of litigation, as well as technical operational plans are outlined. These plans include projects to evaluate the matching process, the…

The mixed model analysis of variance assumes a mathematical property known as sphericity. Several preliminary tests have been proposed to detect departures from the sphericity assumption. The logic of the preliminary testing procedure is to conduct the mixed model analysis of variance if the preliminary test suggests that the sphericity assumption…

Since meta-analysis was described in 1976 (Glass) as the application of familiar experimental methods to the integration of available research, at least five coherent approaches to meta-analysis have appeared in common use. These approaches can be divided into two broad groups. In the first group (including procedures by Robert Rosenthal, Larry…

A Rasch measurement model can be constructed to meet the requirements of rank ordered data. If multiple rankings of the same objects are available, then the parameters of the objects can be estimated, along with their standard errors and also with statistics summarizing the fit of the data to the measurement model. This paper summarizes the…

Meta-analysis has become an important supplement to traditional methods of research reviewing, although many problems must be addressed by the reviewer who carries out a meta-analysis. These problems include identifying and obtaining appropriate studies, extracting estimates of effect size from the studies, coding or classifying studies, analyzing…

According to classical test theory, the presence of random measurement error in a psychological test has important implications for validation studies. The more comprehensive application of classical test theory in construct validation is distinguished from that in criterion-oriented validation. Critics of thematic apperceptive measurement of the…

The objective of this paper is to examine the relationship between the unreliability of difference scores and the power of tests of significance in an attempt to determine the validity of the paradox for the measurement of change presented by Overall and Woodward: that the power of tests of significance is maximum when the reliability of the…