More important than good grades. . .

It's report card day for the nation's public schools, and the news is generally encouraging. Math scores are up on the National Assessment of Educational Progress, younger students are reading better, more students with disabilities and limited English proficiency are in the pool and overall performance is slowly rising.

But year-to-year gains or losses are only part of the reason why this testing program matters. More important than how states did in a given year is the fact that we now measure their progress annually, report it by a common yardstick, and give policymakers and citizens a way to compare states' performance. The NAEP results also give us ongoing feedback on the achievement gap between white and minority students, information that should goad us to get to the heart of the disparity.

Standardized testing has brought both benefit and detriment, but its greatest good is an insistence on reliable and consistent data by which to measure performance and direct improvement.