help sizefx-------------------------------------------------------------------------------

Title

sizefx-- Calculate Cohen'sd, Hedges'g, and the effect size (ES) correlation > (r)

Syntax

sizefxvarlist[if] [in]

Description

sizefxcomputes Cohen'sd, Hedges'g, and effect size (ES) correlations (r) for the two variables specified invarlist. The two variables specified correspond to the variables in attest, although the "==" operator is not used in thesizefxsyntax.The command displays Cohen's

dstatistic (Cohen 1988) using the pooled variance of the variables and Hedges'gstatistic. The pooled variance for an unpaired t-test is used to calculate effect size even when using a dependent sample or correlated designs (Dunlap et al. 1996).Additionally, it displays the effect size (ES) correlation (

r) using the value of Cohen'sd.

Examples.

sizefxage1 age2 .sizefxbefore after

ReferencesCohen, J. (1988)

Statistical power analysis for the behavioral sciences,2nd ed. Hillsdale, NJ: Lawrence Earlbaum Associates.Dunlap, William P., Cortina, Jose M., Vaslow, Joel B., and Burke, Michael J. (1996) Meta-analysis of experiments with matched groups or repeated measures designs.

Psychological Methods1 no. 2, 170-177.Thalheimer, W., and Cook, S. (2002, August)

How to calculate effect sizesfrom published research articles: A simplified methodology. Retrieved 01 Apr 2010 from http://work-learning.com/effect_sizes.htm.Additional resources may be found at: http://www.gseis.ucla.edu/courses/ed230a2/notes/effect.html http://web.uccs.edu/lbecker/Psy590/es.htm

Links active as of 01 Apr 2010.

AuthorMatthew S. Openshaw, The University of Texas at Dallas, USA openshaw@utdallas.edu

Please send comments, suggestions or constructive criticism to the above email address.

sizefx v1.3 Update 01 Apr 2010