We conducted a theory-based analysis of the underlying structure of the Tripod student perception survey instrument using the Measures of Effective Teaching (MET) database (N = 1,049 middle school math class sections; N = 25,423 students). Multilevel item factor analyses suggested that an alternative bifactor structure best fit the Tripod items,…

Education agencies are evaluating teachers using student achievement data. However, very little is known about the comparability of test-based or "value-added" metrics across districts and the extent to which they capture variability in classroom practices. Drawing on data from four urban districts, we found that teachers were…