A test for multisample sphericity based on the efficient scores criterion is obtained as an alternative to the likelihood ratio test developed by Mendoza. (Author)

The purposes of this article are (1) to present a method by which social security numbers may be used to draw cluster samples of a predetermined size and (2) to describe procedures used to validate this method of drawing random samples. (JOW)

This technical paper examines the issue of attrition bias in two cohorts of the Longitudinal Surveys of Australian Youth (LSAY), based on an analysis using data from 1995 to 2002. Data up to 2002 provided eight years of information on members of the Y95 cohort and five years of information on members of the Y98 cohort. This study suggests that…

Presents a statistical technique that yields consistent estimates for censored samples. Application of this technique to models related to selection bias and the presence of depression indicate that the prevalence of this disorder in mental health center populations approaches 44 percent rather than the 25 percent from a censored sample.…

It is argued that time generalizability exists independent of population and situation generalizability, although the three may interact. Problems associated with sampling and randomization efficacy over time are discussed. (Author/GK)

The use of stepwise methodologies has been sharply criticized by several researchers, yet their popularity, especially in educational and psychological research, continues unabated. Stepwise methods have been considered particularly well suited for use in regression and discriminant analyses, but their use in discriminant analysis (predictive…

This article builds on an earlier discussion of the importance of the Type II error (beta) and power to the hypothesis testing process (CE 511 484), and illustrates the methods by which sample size calculations should be employed so as to improve the research process. (Author/CT)

Addresses issue of range enhancement effects on correlations, asserting that, while adding to or deleting from sample can affect variance and correlation in sample, increases or decreases in individual differences in intact sample resulting from such factors as history, maturation, training, and experience will not necessarily affect correlations.…

Describes a sampling strategy which involves linked pairs of persons used to obtain bereaved respondents for a study examining loss and coping responses following a recent natural disaster. The sampling procedure appeared not to produce an obvious bias and was very beneficial in meeting the research objectives. (Author/NRB)

As a result of rejection by personnel psychologists of the erroneous law of small numbers and of the adoption of correct inferential procedures, the future of criterion-related validity promises to be bright. Probable future developments include widespread appreciation of the low statistical power characteristic of small samples. (Author)

An experimental sampling procedure for communities on which coal had been surface-mined yielded missing cells and caused the number of degrees of freedom to be N instead of the usual N minus one. The apparent discrepancy is explained, and a solution to the problem is presented. (Author/JKS)

A study of the reported sampling methods and respondent/subject characteristics in 297 published communication research studies suggests that the vast majority of published communication research literature does not meet minimal scholarly standards for reporting research results. (GT)

Three problems with stepwise research methods are explored. Computer packages may use incorrect degrees of freedom in stepwise computations. In addition, stepwise methods do not identify correctly the best variable set of a given size. A third problem is that stepwise methods tend to capitalize on sampling error. (SLD)

Notes that family researchers can examine extent of self-selection bias in samples by using range of "plausibly correlated characteristics" such as marriage and divorce public records. Provides extensive case example of analyses and discusses compensation techniques of weighting and hazard rate models. (Author/NB)

This document describes the flaws in an October 2007 Wisconsin Policy Research Institute (WPRI) report on public school choice and parental involvement, "Fixing the Milwaukee Public Schools: The Limits of Parent-Driven Reform." Because the report claims that public school choice and parental involvement have little effect on student…