Makes the case that science is best served when researchers focus on the size of effects and their practical significance. Advocates the use of confidence intervals for deciding whether chance or sampling variability is an unlikely explanation for an observed effect. Calls for more emphasis on effect sizes in the next edition of the American…

Investigates significance tests as a tool for helping to identify real effects in the face of random variation. Speculates that equivalence tests improve the logic of significance testing when demonstrating similarity is important. Reverse tests can help show that failure to reject a null hypothesis does not support that hypothesis. (Contains 30…

Wider use in psychology of confidence intervals (CIs), especially as error bars in figures, is a desirable development. However, psychologists seldom use CIs and may not understand them well. The authors discuss the interpretation of figures with error bars and analyze the relationship between CIs and statistical significance testing. They propose…

In this article, the authors (a) illustrate how displaying disattenuated correlation coefficients alongside their unadjusted counterparts will allow researchers to assess the impact of unreliability on bivariate relationships and (b) demonstrate how a proposed new "what if reliability" analysis can complement null hypothesis significance…

A critical reanalysis of Barrett, Caldwell, and Alexander's (1985) critique of dynamic criteria. Summarizes and questions Barrett, et al.'s three definitions of dynamic criteria and their conclusion that reported temporal changes in criteria could be explained by methodological artifacts. A greater focus on dynamic criteria as constructs is…

Responds to Austin, Humphreys, and Hulin's (1989) critique of Barrett, Caldwell, and Alexander, suggesting that the burden of proof still rests on the advocates of the concept of dynamic criteria, and that empirical support is lacking for the existence of dynamic criteria as a simplex. Contrary evidence from educational, organizations, and…

This commentary on EC 603 695 argues that significance testing is a necessary but insufficient condition for positivistic research, that judgment-based assessment and single-subject research are not substitutes for significance testing, and that sampling fluctuation should be considered as one of numerous epistemological concerns in any…

Statistical significance reporting and use in educational and psychological research is reviewed. An assessment of the use of statistical significance in articles published in MECD from 1990-1996 is presented. The elements of statistical significance (including sample size, effect size, and power), interpretation of results, common erroneous…

Addresses the state of the art in use of statistical significance tests and effect size interpretation, explicating the current debate regarding hypothesis testing; reviewing the newly published American Psychological Association Task Force on Statistical Inference report on statistical inference; examining current trends in reporting practices in…

The use of measures of magnitude of effect has been advocated as a way to go beyond statistical tests of significance and to identify effects of a practical size. They have been used in meta-analysis to combine results of different studies. Describes problems associated with measures of magnitude of effect (particularly study size) and…

Researchers, journal editors, textbook authors, and those responsible for writing publication manuals must work together to enhance the thoughtful reporting of statistical results and to make clear the necessity for reporting effect sizes. (SLD)

Suggests that researchers should report the results of appropriate significance tests and the effect sizes associated with each test. Discusses the roles of textbook authors, publication manuals, and journal editors in leading the movement to better statistical reporting. (SLD)

Documents the recent use of one-tailed F-tests in communication journals, and examines the arguments both for and against their use. Examines the use of these tests within the broader unresolved controversy surrounding the use of one-tailed tests. Recommends that future researchers should most often avoid one-tailed Fs, and generally exercise…

Since the 1993 APA task force of the Society of Clinical Psychology developed guidelines to apply data-based psychology to the identification of effective psychotherapy, there has been an increasing number of texts focussing on Empirically based Psychotherapy and Empirically Supported Treatments. This manuscript examines recent key texts and…

Despite the increasing criticism of statistical significance testing by researchers, particularly in the publication of the 1994 American Psychological Association's style manual, statistical significance test results are still popular in journal articles. For this reason, it remains important to understand the logic of inferential statistics. A…