The tetrachoric correlation describes the linear relation between two continuous variables that have each been measured on a dichotomous scale. The treatment of the point estimate, standard error, interval estimate, and sample size requirement for the tetrachoric correlation is cursory and incomplete in modern psychometric and behavioral…

Large numbers of rural districts have experienced sharp declines in enrollment, unlike their suburban counterparts. Accurate enrollment projections are required, whether a district needs to build new schools or consolidate existing ones. For school districts having more than 600 students, a quantitative method such as the Cohort-Survival Ratio…

In textbook treatments of enzyme inhibition kinetics, adjustment of the initial inhibitor concentration for inhibitor bound to enzyme is often neglected. For example, in graphical plots such as the Dixon plot for estimation of an inhibition constant, the initial concentration of inhibitor is usually plotted instead of the true inhibitor…

Among the varied analytical challenges institutional researchers face, examining faculty pay may be one of the most vexing. Although the literature on faculty compensation analysis dates back to the 1970s (Loeb and Ferber, 1971; Gordon, Morton, and Braden, 1974; Scott, 1977; Braskamp and Johnson, 1978; McLaughlin, Smart, and Montgomery, 1978),…

It is a widely held belief that anchor tests should be miniature versions (i.e., minitests), with respect to content and statistical characteristics of the tests being equated. This paper examines the foundations for this belief. It examines the requirement of statistical representativeness of anchor tests that are content representative. The…

The objectives of this study were to generate precise estimates of suicide rates in the military while controlling for factors contributing to rate variability such as demographic differences and classification bias, and to develop a simple methodology for the determination of statistically derived thresholds for detecting significant rate…

In general, it is assumed that distinct true values will be found behind what is actually measured in surveys. By acquiring sufficient knowledge of measurement error, its extent and nature, we are supposed to be able to obtain adequate knowledge of underlying properties. It could be maintained, however, that this idea of a stable and…

Oversampling and cluster sampling must be addressed when analyzing complex sample data. This study: (a) compares parameter estimates when applying weights versus not applying weights; (b) examines subset selection issues; (c) compares results when using standard statistical software (SPSS) versus specialized software (AM); and (d) offers…

Because there is no commonly accepted view of what makes for good writing, automated essay scoring (AES) ideally should be able to accommodate different theoretical positions, certainly at the level of state standards but also perhaps among teachers at the classroom level. This paper presents a practical approach and an interactive computer…

The present study used an ecological framework to examine the relationships among adolescents' perceptions of school climate, social competence, and behavioral and psychological adjustment in the middle school years. This study improved upon prior studies by using "structural equation modeling" to investigate the hypothesized mediating…

As performance-based assessments have gained wider use, there are increasing concerns about their dependability. This study is a synthesis of existing studies regarding the reliability or generalizability of performance assessments. The meta-analysis involves summarizing, examining, and evaluating research findings. Articles on the dependability…

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…