It's almost a given that when NCLB is finally reauthorized, schools will be allowed--if not required--to use value-added data to determine if they have made AYP. A new paper by Doug Harris makes a convincing argument that accountability models should include both value-added as well as the much-maligned proficiency data used under the current NCLB regime.

In an unusually understandable description of performance measures, Harris recaps the limitations of the proficiency-based model and the necessity of moving toward measures that instead judge schools on what they contribute to student learning. But, Harris notes, value-added isn't without some of the same kinds of perverse incentives found under NCLB. If the current AYP model unintentionally encourages schools to focus on "bubble kids," a value-added model could lead schools to ignore the early grades, in order to maximize growth in tested grades. The emphasis on growth could also lead schools to alternate stronger teachers with weaker teachers between grades, the very opposite of what is needed to close the achievement gap.

His solution is to use a "School Performance Table," an index that integrates both value-added data and the percentage of students at proficiency. Therefore, a school that starts off with lots of grade-level kids but achieves little growth--a school now deemed successful--would instead be identified for intervention. And a school not yet hitting proficiency targets but making substantial gains nevertheless would face no sanctions.

Harris points out the flaws in the current system play right into the hands of those who oppose any kind of accountability. The next system cannot just be different; it has to be better.