ERIC Number: ED222579
Record Type: Non-Journal
Publication Date: 1982-Aug
Reference Count: N/A
Credible Comparison of Instructional Program Impact: The RAGS Procedure. Report No. 328.
Fennessey, James; Salganik, Laura Hersh
An explicit model identifying 10 relevant components of achievement gain scores has been developed. Based on that model, all students under consideration are stratified according to individual observed pretest score, and achievement gains are measured relative to the average and range of gains among students in the same prescore stratum. The resulting index, RAGS, is based on the Rescaled and Adjusted Gains within Stratum. Stratification by prescore controls well for the the biases identified in the decomposition of gain scores, and so allows the fairest practical comparison of program impacts. The RAGS reports also provide other data that allow educational managers to compare detailed impact patterns. By viewing the RAGS indices as useful approximations, and by institutionalizing a systematic procedure for critiquing and refining the index construction process, educators have available one major component of an overall program assessment system that is informative, feasible, and self-improving. (Author)
Publication Type: Reports - Evaluative
Education Level: N/A
Sponsor: National Inst. of Education (ED), Washington, DC.
Authoring Institution: Johns Hopkins Univ., Baltimore, MD. Center for Social Organization of Schools.