Percentile Growth Modeling
Nov. 1, 2011
Percentile Growth Modeling: A Policy Response to Educational Accountability
by R. Martin Reardon (November 2011)
In the following, I will commence by briefly considering the policy context from which the discussion of rewards and performance has emerged. I then touch on the emergence of the current emphasis on teacher quality, and some of the key issues involved in the practical application of such an ephemeral concept. I then move into a more comprehensive overview of the appealing concept of “value added,” and how this concept operationalizes “teacher quality.” I then portray the observed instability of early value-added measures as motivating a percentile growth modeling approach which compares each individual student’s performance to that of his or her peers on the basis of his or her past performance in relation to those same peers. I propose that the current focus on educational accountability is well served by taking cognizance of the perennial injunction to teachers to refrain from making summative judgement on the basis of a single indicator and applying it to teachers. This is the hallmark of a policy that will appropriately guide judgements of teacher performance and potential consideration of teacher rewards, with which prospect this paper closes.