ERIC Number: EJ747791
Record Type: Journal
Publication Date: 2006-Jun
Reference Count: 0
Assessing Heterogeneity in Meta-Analysis: Q Statistic or I[squared] Index?
Huedo-Medina, Tania B.; Sanchez-Meca, Julio; Marin-Martinez, Fulgencio; Botella, Juan
Psychological Methods, v11 n2 p193-206 Jun 2006
In meta-analysis, the usual way of assessing whether a set of single studies is homogeneous is by means of the Q test. However, the Q test only informs meta-analysts about the presence versus the absence of heterogeneity, but it does not report on the extent of such heterogeneity. Recently, the I[squared] index has been proposed to quantify the degree of heterogeneity in a meta-analysis. In this article, the performances of the Q test and the confidence interval around the I[squared] index are compared by means of a Monte Carlo simulation. The results show the utility of the I[squared] index as a complement to the Q test, although it has the same problems of power with a small number of studies.
Descriptors: Meta Analysis, Intervals, Monte Carlo Methods, Comparative Analysis, Q Methodology, Methods Research, Evaluation Research, Construct Validity, Research Problems, Heterogeneous Grouping, Homogeneous Grouping
American Psychological Association. Journals Department, 750 First Street NE, Washington, DC 20002-4242. Tel: 800-374-2721; Tel: 202-336-5510; Fax: 202-336-5502; e-mail: email@example.com; Web site: http://www.apa.org/publications
Publication Type: Journal Articles; Reports - Evaluative
Education Level: N/A
Authoring Institution: N/A