Effect Sizes for 2×2 Contingency Tables
Open Access
- 7 March 2013
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLOS ONE
- Vol. 8 (3), e58777
- https://doi.org/10.1371/journal.pone.0058777
Abstract
Sample size calculations are an important part of research to balance the use of resources and to avoid undue harm to participants. Effect sizes are an integral part of these calculations and meaningful values are often unknown to the researcher. General recommendations for effect sizes have been proposed for several commonly used statistical procedures. For the analysis of tables, recommendations have been given for the correlation coefficient for binary data; however, it is well known that suffers from poor statistical properties. The odds ratio is not problematic, although recommendations based on objective reasoning do not exist. This paper proposes odds ratio recommendations that are anchored to for fixed marginal probabilities. It will further be demonstrated that the marginal assumptions can be relaxed resulting in more general results.Keywords
This publication has 18 references indexed in Scilit:
- Bicycle Helmet Wearing Is Not Associated with Close Motor Vehicle Passing: A Re-Analysis of Walker, 2007PLOS ONE, 2013
- Statistical power analyses using G*Power 3.1: Tests for correlation and regression analysesBehavior Research Methods, 2009
- An effect size primer: A guide for clinicians and researchers.Professional Psychology: Research and Practice, 2009
- Drivers overtaking bicyclists: Objective data on the effects of riding position, helmet use, vehicle type and apparent genderAccident Analysis & Prevention, 2006
- Effect Size Estimation: Factors to Consider and Mistakes to AvoidJournal of Management, 2003
- Some Practical Guidelines for Effective Sample Size DeterminationThe American Statistician, 2001
- Using odds ratios as effect sizes for meta-analysis of dichotomous data: A primer on methods and issues.Psychological Methods, 1998
- A power primer.Psychological Bulletin, 1992
- Phi/Phimax: Review and SynthesisEducational and Psychological Measurement, 1991
- The factorial interpretation of test difficultyPsychometrika, 1941