"We need triage," Madame Secretary explained last week. This morning, Randy Reback delivered it to my inbox via the Journal of Public Economics' new issue, which includes his paper, "Teaching to the Rating: School Accountability and the Distribution of Student Achievement." Reback analyzed data from Texas, the birthplace of NCLB-style accountability, and here's what he found:

* Schools respond to math performance incentives both by targeting math resources towards specific students and by making broad changes which also help very low achieving students. These responses tend to sacrifice the targeted students’ reading performance and to sacrifice relatively high achieving students’ performance in both math and reading.

* Schools respond to reading performance incentives by targeting resources towards the reading performance of particular students, sacrificing these students’ math performance and sacrificing all other students’ performance in reading.

* Finally, schools devote fewer resources towards students in the terminal grades during years when short-run incentives are low than during years when incentives are high.

Reback concluded:

Whether the finding of non-trivial distributional effects is a positive or negative outcome of this public policy is entirely subjective. If one of the primary goals is to create a sort of educational triage, in which students below minimum grade-level skills are pushed up, then the No Child Left Behind type of accountability system appears to be fairly effective. Furthermore, the results say nothing about the overall impact of this system on performance: it may be a rising tide that lifts all boats (and lifting some more than others), or it may be a falling tide sinking all boats (and sinking some less than others).

The important lesson here is that schools respond to the specific instructional incentives created by the accountability system. Schools' responses include targeting specific students, targeting specific subjects, and making broad changes which affect all students. An accountability system should only create disproportionate incentives concerning student achievement gains if the intention is to help some students more than others and to boost performance in some subjects by more than others. Otherwise, the optimal accountability system requires a more evenhanded approach.