Our research in statistical cognition uses both qualitative and quantitative methods. A mixed method approach makes our research more comprehensive, and provides us with new directions, unexpected insights, and alternative explanations for previously established concepts. In this paper, we review four statistical cognition studies that used mixed…

Compelling arguments for reform of statistical practices have been made in many disciplines, in some cases over several decades, but achieving reform has proved difficult. We discuss how reform has progressed--or not progressed--in psychology, medicine, and ecology and describe case studies of attempts by pioneering journal editors to change…

Practitioners and teachers should be able to justify their chosen techniques by taking into account research results: This is evidence-based practice (EBP). We argue that, specifically, statistical practice and statistics education should be guided by evidence, and we propose statistical cognition (SC) as an integration of theory, research, and…

Identifies deficiencies in the new edition of the American Psychological Association's "Publication Manual," drawing on interviews with some critics and other parties. These include lack of follow-through with explanations and examples of how to report the statistics now recommended. (SLD)

Illustrates the computation of confidence intervals for effect sizes for some analysis of variance applications and shows how the use of intervals involving noncentral distributions is made practical by new software. (SLD)

Little is known about researchers' understanding of confidence intervals (CIs) and standard error (SE) bars. Authors of journal articles in psychology, behavioral neuroscience, and medicine were invited to visit a Web site where they adjusted a figure until they judged 2 means, with error bars, to be just statistically significantly different (p…

Philip Kendall's (1997) editorial encouraged authors in the Journal of Consulting and Clinical Psychology (JCCP) to report effect sizes and clinical significance. The present authors assessed the influence of that editorial--and other American Psychological Association initiatives to improve statistical practices--by examining 239 JCCP articles…