It Depends. It Always Depends.

My favorite education research is what I call "Well, duh, research" -- that is, research in which smart people spend a lot of time documenting what practitioners consider to be common sense.

That sounds as if I am being snarky, but I'm not. Common sense isn't all that common, unfortunately -- particularly in the broad field of education. "Well, duh research" can give serious educators a firm foothold with which to fight off the faddish nonsense that plagues the field.

One example of what I consider to be "well, duh, research" was a large study done by a team led by Ken Leithwood at the University of Toronto that detailed how school leadership is crucial to school improvement. "To date we have not found a single case of a school improving its student achievement record in the absence of talented leadership," concluded the study.

Most teachers -- and common sense -- could have told you that principals often make the difference between good schools and bad ones. But until that study, plenty of people who mess around in the field of education considered principals to be middle managers of little consequence and paid little attention to what principals did or the role they could play in improving schools. The Leithwood team demonstrated that to be a grave oversight.

All of which is to say that for me the term "well, duh, research," is far from an insult.

Recently a new piece of research, though not as far-reaching as the Leithwood study, elicited a "well, duh" reaction from me.

It attempted to quantify what principals do, precisely, to be so crucial in school improvement. It began with the idea that principals are now supposed to be "instructional leaders" -- that is, not simply middle managers -- and examined an activity that is often associated with instructional leadership, which is "walkthroughs."

Walkthroughs, which have become very popular, are quick dips into classrooms to observe and assess instruction; many principals are actually required to do them. The question is, are they helpful? This new study says (drumroll, please) that depends.

If they're done just to establish the visibility of the principal and to monitor whether teachers are doing what they're told to do, the study found, then they are not just a potential waste of time but a harmful waste of time. Or, as the study says, "negatively associated with outcomes."

The study's authors -- Jason Grissom, Benjamin Master, and the redoubtable Susannah Loeb -- assigned researchers to shadow 100-plus principals in the Miami-Dade school district and document their actions in five-minute intervals. They supplemented that time study with interviews and student achievement data from the principals' schools. In collating all that information -- which principals' schools showed improvement and how they approached walkthroughs -- the authors said pretty definitively, "we find a negative association between time spent on walkthroughs and outcomes."

But they went further, breaking apart the data and finding that walkthroughs can be helpful, but only when principals use them to provide direct coaching and feedback and to gather information about what professional development teachers need. Or, as the study says, "Schools are likely better served if principals spend more time using the information for school improvement than collecting it."

In writing about the Grissom, Masters, Loeb study, cognitive scientist Dan Willingham said it suggests "a general principle of instructional leadership that fits well with one overarching principle of learning: Feedback is essential. Instructional leadership activities that offer meaningful feedback to teachers may help. Those that don't, will not."

All I can say is, "Well, duh."