"It's about instruction, stupid." That 2001 headline, which appeared in Catalyst, the magazine of record about Chicago school reform, says a lot about what has happened—and what hasn't—in the first decade of reforms. Despite some notable successes at individual schools, there is this striking fact: one-third of schools have improved, one-third are treading water, and another third appear dead in the water. Why such disparities? Books could—and will—be written dissecting that question. But one answer heard more often than not these days is "instruction."

In the last issue of the Harvard Education Letter, we highlighted research showing the importance of strong, trusting relationships in schools—the power of social trust as an agent of school reform. In successful schools, the development of trust between administrators and teachers —and among teachers themselves—depends in large part on the amount of respect they have in each others' instructional abilities. Trust begins first and foremost with the question, Is this person committed to and capable of high-quality teaching?

The Consortium on Chicago School Research—a group of researchers from local universities, community groups, and the school system—has conducted a number of studies in an effort to identify why some Chicago schools are improving while most are not. Much of that work has focused on instruction.