TY - JOUR

T1 - Improving interpretability

T2 - Gamma as an alternative to R-2 as a measure of effect size

AU - Reidpath, Daniel D

AU - Diamond, Mark R

AU - Hartel, Gunter

AU - Glasziou, P

PY - 2000/5/30

Y1 - 2000/5/30

N2 - A traditional measure of effect size associated with tests for difference between two groups is the variance explained by group membership (R-2). If exposure to a disease causes a small but long term deficit in performance, however, R-2 does not capture that cumulating effect. We propose an alternative statistic, gamma, based on the probability of an unexposed person outperforming an exposed person. Although gamma is also a point estimate, it more easily conveys what the cumulating effect of a deficit would be. We discuss some of the advantages of this measure. Copyright (C) 2000 John WiIey & Sons, Ltd.

AB - A traditional measure of effect size associated with tests for difference between two groups is the variance explained by group membership (R-2). If exposure to a disease causes a small but long term deficit in performance, however, R-2 does not capture that cumulating effect. We propose an alternative statistic, gamma, based on the probability of an unexposed person outperforming an exposed person. Although gamma is also a point estimate, it more easily conveys what the cumulating effect of a deficit would be. We discuss some of the advantages of this measure. Copyright (C) 2000 John WiIey & Sons, Ltd.

U2 - 10.1002/(SICI)1097-0258(20000530)19:10<1295::AID-SIM493>3.0.CO;2-Z

DO - 10.1002/(SICI)1097-0258(20000530)19:10<1295::AID-SIM493>3.0.CO;2-Z

M3 - Article

VL - 19

SP - 1295

EP - 1302

JO - Statistics in Medicine

JF - Statistics in Medicine

SN - 0277-6715

IS - 10

ER -