ERIC Number: ED392822
Record Type: RIE
Publication Date: 1995-Apr
Reference Count: N/A
An Empirical Study of the Hedges (1982) Homogeneity Test.
The test of homogeneity developed by L. V. Hedges (1982) for the fixed effects model is frequently used in quantitative meta-analyses to test whether effect sizes are equal. Despite its widespread use, evidence of the behavior of this test for the less-than-ideal case of small study sample sizes paired with large numbers of studies is contradictory, and its behavior for nonnormal score distributions in primary studies is an open question. The results of a Monte Carlo study indicated that the Type I error rate and power of the homogeneity test were insensitive to skewed score distributions, but were very sensitive to smaller study sample sizes paired with larger numbers of studies. These findings extend earlier results and help to clarify the statistical behavior of the homogeneity test. Specifically, the pairing of small study sample sizes with large numbers of studies tends to produce conservative Type I error rates for the homogeneity test and underestimates its power, increasing the likelihood of Type II errors. (Contains 2 tables and 23 references.) (Author/SLD)
Publication Type: Reports - Evaluative; Speeches/Meeting Papers
Education Level: N/A
Authoring Institution: N/A
Identifiers: Fixed Effects; Homogeneity Tests; Type I Errors
Note: Paper presented at the Annual Meeting of the American Educational Research Association (San Francisco, CA, April 18-22,1995).