The sense that replicability is an important aspect of empirical science led Killeen (2005a) to define "p[subscript rep]," the probability that a replication will result in an outcome in the same direction as that found in a current experiment. Since then, several authors have praised and criticized 'p[subscript rep]," culminating…

This comment offers three descriptions of "p[subscript rep]" that start with a frequentist account of confidence intervals, draw on R. A. Fisher's fiducial argument, and do not make Bayesian assumptions. Links are described among "p[subscript rep]," "p" values, and the probability a confidence interval will capture…

Considers objections to comparisonwise position, which holds that, when conducting simultaneous significance procedures, per-test Type I error rate should be controlled and that it is unnecessary to introduce adjustments designed to control familywise rate. Objections collected by Saville in an attempt to refute them are discussed along with…

D. Trafimow presented an analysis of null hypothesis significance testing (NHST) using Bayes's theorem. Among other points, he concluded that NHST is logically invalid, but that logically valid Bayesian analyses are often not possible. The latter conclusion reflects a fundamental misunderstanding of the nature of Bayesian inference. This view…

Written by a social worker for social work students, this is a nuts and bolts guide to statistics that presents complex calculations and concepts in clear, easy-to-understand language. It includes numerous examples, data sets, and issues that students will encounter in social work practice. The first section introduces basic concepts and terms to…

The Behrens-Fisher problem arises when one seeks to make inferences about the means of two normal populations without assuming the variances are equal. This paper presents a review of fundamental concepts and applications used to address the Behrens-Fisher problem under fiducial, Bayesian, and frequentist approaches. Methods of approximations to…

The APA Task Force on Statistical Inference recently recommended reporting effect sizes alongside results of statistical significance tests. The purpose of this article is to investigate effect size usage in gifted education research and to follow up on a similar investigation published by Plucker (1997). A content analysis of effect size…

Many evaluation students are still being taught the use of tests of statistical significance without being warned about their limitations. This paper discusses other estimates of treatment effects necessary to interpret between-group differences correctly. Sources to improve evaluation practice are also suggested. (SLD)

Responds to Biskin's comments (this issue) on the significance test controversy. Highlights areas of agreement (importance of replication evidence, importance of effect sizes) and disagreement (influence of sample size, evaluation of populations vs. samples, significance of Carver's article). Includes further recommendations for reporting research…

Analyzed 150 articles from the "Journal of Applied Psychology" (JAP) from 1940 to 1999 to determine statistical reporting practices related to null hypothesis significance testing, American Psychological Association guidelines, and reform recommendations. Findings show little evidence that decades of cogent criticisms by reformers have…

Many research-related classes in social sciences present probability as a unified approach based upon mathematical axioms, but neglect the diversity of various probability theories and their associated philosophical assumptions. Although currently the dominant statistical and probabilistic approach is the Fisherian tradition, the use of Fisherian…

This paper addresses the state of the art regarding the use of statistical significance tests (SSTs). How social science research will be conducted in the future is impacted directly by current debates regarding hypothesis testing. This paper: (1) briefly explicates the current debate on hypothesis testing; (2) reviews the newly published report…

Significance tests are often used inappropriately in counseling research. In addition to comments on the significance test controversy (Vacha-Haase and Nilsson, this issue), a wider historical context and personal experiences are provided. The controversy is discussed, and seven recommendations for using significance tests are included. (EMK)

Introduces the three subsequent articles from this special section, which extend the discussion of future prospects for progress in the reporting and interpreting of effect sizes by researchers. The authors of these pieces represent diverse views. (SLD)

Discusses three topics related to interpretation of discriminant analyses (DA's): (1) partial F ratios and partial Wilks's lambdas for predictor variables in standard, step-down, and stepwise DA's; (2) relation of goals of classification to definition/evaluation of classification rules; and (3) significance tests for total hit rates in internal…