The Stability of Teacher Effects Upon Student Achievement

This review focuses on the stability, or consistency, of effectiveness. In the review the term teacher refers to residual class mean achievement scores in which a measure of prior achievement or student aptitude is used to adjust posttest scores by regression. Although there have been numerous studies seeking to determine the correlates of effects within a given time period, much less effort has been devoted to assessing the consistency of effects across two intervals (e.g., two lessons or two years). This paper reviews and discusses nine studies concerned with the generality of effects across two instructional periods. Nine studies are too few to support any conclusions, especially when the designs of the studies were not equally rigorous. Therefore, one of the purposes of writing the review is to call attention to the existing research in this area, and to the problems in interpreting the results. It is hoped that future studies will be conducted to replicate the existing studies and to help resolve some of the issues which they raise.