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ERIC Number: ED508284
Record Type: Non-Journal
Publication Date: 2008-Nov
Pages: 7
Abstractor: ERIC
Reference Count: 14
Overview of Measuring Effect Sizes: The Effect of Measurement Error. Brief 2
Boyd, Don; Grossman, Pam; Lankford, Hamp; Loeb, Susanna; Wyckoff, Jim
National Center for Analysis of Longitudinal Data in Education Research
The use of value-added models in education research has expanded rapidly. These models allow researchers to explore how a wide variety of policies and measured school inputs affect the academic performance of students. An important question is whether such effects are sufficiently large to achieve various policy goals. Judging whether a change in student achievement is important requires some meaningful point of reference. In certain cases a grade-equivalence scale or some other intuitive and policy relevant metric of educational achievement can be used. However, this is not the case with item response theory (IRT) scale-score measures common to the tests usually employed in value-added analyses. In such cases, researchers typically describe the impacts of various interventions in terms of "effect sizes", although conveying the intuition of such a measure to policymakers often is a challenge. This paper provides an overview of measuring effect sizes and explains the effect of measurement error. (Contains 2 tables and 6 notes.)
National Center for Analysis of Longitudinal Data in Education Research. The Urban Institute, 2100 M Street NW, Washington, DC 20037. Tel: 202-261-5739; Fax: 202-833-2477; e-mail:; Web site:
Publication Type: Reports - Evaluative
Education Level: Adult Education; Elementary Secondary Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: Urban Institute