Distribution Theory for Glass's Estimator of Effect size and Related Estimators

Larry V. Hedges

Journal of Educational and Behavioral Statistics, 1981, vol. 6, issue 2, 107-128

Abstract: Glass's estimator of effect size, the sample mean difference divided by the sample standard deviation, is studied in the context of an explicit statistical model. The exact distribution of Glass's estimator is obtained and the estimator is shown to have a small sample bias. The minimum variance unbiased estimator is obtained and shown to have uniformly smaller variance than Glass's (biased) estimator. Measurement error is shown to attenuate estimates of effect size and a correction is given. The effects of measurement invalidity are discussed. Expressions for weights that yield the most precise weighted estimate of effect size are also derived.

Keywords: Meta-analysis; Research synthesis; Standardized mean difference; Measurement error; Weighting of estimators; Invalidity; confidence intervals (search for similar items in EconPapers)
Date: 1981
References: Add references at CitEc
Citations: View citations in EconPapers (18)

Downloads: (external link)
https://journals.sagepub.com/doi/10.3102/10769986006002107 (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:sae:jedbes:v:6:y:1981:i:2:p:107-128

DOI: 10.3102/10769986006002107

Access Statistics for this article

More articles in Journal of Educational and Behavioral Statistics
Bibliographic data for series maintained by SAGE Publications ().