Beyond Significance Testing: Reforming Data Analysis Methods in Behavioral Research

Article excerpt

REX B. KLINE Beyond Significance Testing: Reforming Data Analysis Methods in Behavioral Research Washington, DC: American Psychological Association, 2004, 336 pages (ISBN 1-59147-118-4, US$49.95 Hardcover)

In 1999, a blue-ribbon task force assembled by the American Psychological Association published their findings with regards to the long-standing controversy pertaining to null hypothesis significance testing (NHST). The task force dictated effect sizes and confidence intervals be reported, and p values and dichotomous accept-reject decisions be given less weight. Editorial policies in a number of journals came to reflect the views of the task force as did a subsequent revision to the American Psychological Association Publication Manual.

Rex B. Kline wrote Beyond Significance Testing. Reforming Data Analysis Methods in Behavioral Research as a follow-up to both the task force recommendations and the revision to the publication manual. Kline's 1998 book Principles and Practice of Structural Equation Modeling (Guilford Press) was well received and a second edition is being published this fall. In Beyond Significance Testing, Kline reviews the controversy regarding significance testing, offers methods for effect size and confidence interval estimation, and suggests some alternative methodologies. There is an accompanying website that includes resources for instructors and students. Part I of the book is a review of fundamental concepts and the debate regarding significance testing. Part II provides statistics for effect size and confidence interval estimation for parametric and nonparametric two-group, oneway, and factorial designs. Part III examines metaanalysis, resampling, and Bayesian estimation procedures.

In the first chapter, Kline provides a scholarly summary of the null hypothesis testing debate concluding with the APA task force findings and what Kline regards as ambiguous recommendations in the publication manual. Kline predicts the future will see a smaller role for traditional statistical testing (p values) in psychology. This change will take time and may not occur until the next generation of researchers are trained, but Kline anticipates the social sciences will then become more like the natural sciences in that "we will report the directions and magnitudes of our effects, determine whether they replicate, and evaluate them for their theoretical, clinical, or practical significance" (p. 15).

Chapter 2 is a review of fundamental concepts of research design, including sampling and estimation, the logic of statistical significance testing, and t, F, and chi-square tests. The problems with statistical tests are revisited in Chapter 3. What follows is a long list of errors in interpretation of p values and conclusions made after null hypothesis testing. The emphasis on null hypothesis significance testing in psychology is also argued to inhibit advancement of the discipline. To be fair, Kline recognizes there is yet no "magical alternative" to statistical tests and that such tests are appropriate in some circumstances when applied correctly. Nonetheless, Kline envisions a future where effect sizes and confidence intervals are reported, substantive rather than statistical significance predominates, and "NHST-Centric" thinking has diminished.

Part II covers effect size and confidence interval calculations. Chapter 4 is a presentation of parametric effect size indexes. Independent and dependent sample statistics are covered separately. The textbook's website has a supplementary chapter on twogroup multivariate designs. Group difference indexes such as d are distinguished from measures of association such as r. Case level analyses of group differences are also reviewed. Sections not relevant to a reader's needs can be skipped without loss of continuity. Interpretive guidelines for effect size magnitude and how one might be fooled by effect size estimation are sections that should not be passed over. …