The value of Value-Added

Here's a study from the Brookings Institution you won't find on the MCEA blog.  Jay Mathews brought it to my attention and he does a good job summarizing the study which focuses on the reliability concerns associated with value-added modeling.   The main idea is that just because a teacher's "percentile rank" might fluctuate year to year- does not mean it is a worthless piece of information.   They compare a teacher's percentile value-added rank to a baseball player's batting average which has similar year to year fluctuations.   Would you make decisions about the current year based on the batting average from last year?   Well, you'd certainly keep it in mind.  From the executive summary:

We believe that whenever human resource actions are based on evaluations of teachers they will benefit from incorporating all the best available information, which includes value-added measures. Not only do teachers typically receive scant feedback on their past performance in raising test scores, the information they usually receive on the average test scores or proficiency of their students can be misleading or demoralizing. High test scores or a high proficiency rate may be more informative of who their students are than how they were taught. Low test scores might mask the incredible progress the teachers made. Teachers and their mentors and principals stand to gain vast new insight if they could see the teachers’ performance placed in context of other teachers with students just like their own, drawn from a much larger population than a single school. This is the promise of value-added analysis. It is not a perfect system of measurement, but it can complement observational measures, parent feedback, and personal reflections on teaching far better than any available alternative. It can be used to help guide resources to where they are needed most, to identify teachers’ strengths and weaknesses, and to put a spotlight on the critical role of teachers in learning.