Can teachers accurately predict student performance?

•Professional development improved teachers' prediction accuracy.•Student achievement increased for high-fidelity implementers.•Prediction accuracy improved for high-fidelity implementers.•Students' test performance was greater for teachers with higher prediction accuracy.

In two studies, we examined the effect of professional development to improve mathematics instruction on the accuracy of teachers' monitoring of student learning. Study 1 was conducted with 36 teachers participating in three years of professional development. Judgment accuracy was influenced by the fidelity with which what was learned in the professional development. Study 2 was conducted with 64 teachers from 8 schools, which were randomly assigned to receive professional development or serve as a control. Judgment accuracy was greater for teachers receiving professional development than for teachers who did not and teachers were better to predict students' computational skills.