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ERIC Number: ED423304
Record Type: Non-Journal
Publication Date: 1998
Pages: 11
Abstractor: N/A
Reference Count: N/A
Improved Confidence Interval Estimation for Variance Components and Error Variances in Generalizability Theory.
Betebenner, Damian W.
The zeitgeist for reform in education precipitated a number of changes in assessment. Among these are performance assessments, sometimes linked to "high stakes" accountability decisions. In some instances, the trustworthiness of these decisions is based on variance components and error variances derived through generalizability theory. Often overlooked is the fact that these statistics are subject to sampling error. This paper introduces techniques used to determine the accuracy of such statistics. It addresses the shortcomings of overlooking sampling error by presenting a number of results with respect to confidence intervals about linear combinations of expected mean squares appropriate for generalizability theory. Simulation results indicate that these intervals, particularly the two-sided and one-sided lower intervals, are accurate or conservative both in simple and complex designs with varying amounts of difference in degrees of freedom across effects. (Contains 1 figure and 12 references.) (Author/SLD)
Publication Type: Reports - Descriptive; Speeches/Meeting Papers
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A