Principals reported that they used walk-throughs to "check up" on teacher performance and to be visible throughout their school. While principals saw the walk-throughs positively, their teachers found them less valuable and even intrusive.
The study published in Educational Researcher (Grissom, Loeb & Master, 2013), gathered data from the Miami-Dade County Public Schools. Observers followed principals one full school day for each of three years. Follow-up interviews with principals provided additional data. This article from Education Week summarizes the findings.
Walk-throughs are widely used in American schools as a tool for instructional improvement. But this study shows there is much to learn about their link to improvement. I'd enjoy hearing from you about the use of walk-throughs in your school.