Table B-8Bias of the ES indexes as a function of the correlation (r) between pretest and post-test

rdhbdhwdbdgds1ds2ds3
.000.0016−0.14760.0000−0.14650.00160.0016−0.1352
.250.0019−0.14740.0001−0.09190.00150.0019−0.1295
.500.0015−0.1474−0.0001−0.00010.00110.0019−0.1118
.750.0017−0.14690.00000.29050.00110.0027−0.0635

Note. See Tables 1 and 2 in the main report for definitions of each ES index. Bias is defined as the M difference between the estimate of the ES and the parametric value. db=Becker’s standardized mean difference; dg=Gibbons’s standardized mean difference. dhb=Hedges’s standardized mean difference using the between-studies degrees of freedom. dhw=Huedo-Medina and Johnson’s standardized mean difference using the within-study degrees of freedom. ds1=Standardized mean difference proposed by Shadish (See Table 2, No. 10). ds2=Standardized mean difference proposed by Shadish using the standard deviation from ANOVA results (See Table 2, No. 11). ds3=Standardized mean difference proposed by Shadish using the standard deviation from ANCOVA results (See Table 2, No. 12). dtch=the standardized mean difference in change-score metric from td. dtra=standardized mean difference in raw-score metric form td.

From: Appendix B, Bias, Efficiency, and Theoretical Variance for All Effect Size Indexes and Their Variances (Specific Aim 2)

Cover of Meta-Analytic Statistical Inferences for Continuous Measure Outcomes as a Function of Effect Size Metric and Other Assumptions
Meta-Analytic Statistical Inferences for Continuous Measure Outcomes as a Function of Effect Size Metric and Other Assumptions [Internet].
Johnson BT, Huedo-Medina TB.

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.