As I discuss below, this does not necessarily constitute a weakness in the accountability design. Such a system does not account for growth in individual student achievement or for differences in student background. It is unlikely that this type of performance indicator primarily reflects factors over which schools have control. Further, under this system, schools whose students start out at a relatively low level of achievement but demonstrate significant academic gains over time, may fail to be recognized as strong performers because less than the required percentage of students reach the benchmark. Other schools, whose students start out at a higher level of achievement but have smaller gains over time, could be recognized as meeting the state benchmark for adequate performance.
Few states come close to the value-added ideal that researchers utilize.
The upside to such a system is that it is both easily understood by the public and relatively inexpensive to administer. O ther states assess performance based on the change in average achievement at a given grade level for different cohorts of students that is, for instance, the average performance of third graders this year compared to the performance of third graders last year. S everal states and school districts have crafted more sophisticated performance-based incentive systems. Although they differ from one another in some respects, these systems compare school-wide gains in student scores over time to what econometric models would predict the gains to be after controlling for student demographic characteristics. However, they are likely to be considerably more costly to administer, because they require more frequent testing as well as data systems that allow the tracking of student performance and educational experience over time.