Reporting point and interval estimates of effect-size for planned contrasts: fixed within effect analyses of variance.
The purpose of this tutorial is threefold: (a) review the state of statistical science regarding effect-sizes, (b) illustrate the importance of effect-sizes for interpreting findings in all forms of research and particularly for results of clinical-outcome research, and (c) demonstrate just how easily a criterion on reporting effect-sizes in research manuscripts can be accomplished. The presentation centers on within-effect analyses of variance including the one-way design for testing pre-post hypotheses and the two-way parallel-groups design for making direct comparisons of competing treatment protocols (e.g., experimental treatment versus control). The presentation is supported with worked examples and a web site containing templates for software applications.


OBJECTIVE
The reader will be able to: (1) explain the rationale for the increased use of estimates of effect-size in reporting results in published research manuscripts; (2) describe what an effect-size is (generally considered) and provide a rationale for its importance; (3) distinguish among the many forms of effect-size and apply their features to the most appropriate choices under specific research circumstances; and (4) appropriately report and interpret effect-sizes.
Robey
Randall R
RR
University of Virginia, P.O. Box 400197, Charlottesville, VA 22904-4197, USA. rrr7w@virginia.edu
D000465:Algorithms; D000704:Analysis of Variance; D002985:Clinical Protocols / Q000592:standards; D016001:Confidence Intervals; D003627:Data Interpretation, Statistical; D006801:Humans; D020407:Internet; D008433:Mathematics; D011643:Publishing / Q000592:standards*; D012107:Research Design / Q000592:standards; D018401:Sample Size; D012984:Software; D016008:Statistical Distributions