This paper examines which configuration of teaching activities maximizes student performance. For this purpose a nonparametric efficiency model is formulated that accounts for (1) self-selection of students and teachers in better schools and (2) complementary teaching activities. The analysis distinguishes both individual teaching (i.e., a personal teaching style adapted to the individual needs of the student) and collective teaching (i.e., a similar style for all students in a class). Moreover, we examine to which group of students the teacher is adapting his/her teaching style. The model is applied on the Trends in International Mathematics and Science Study 2003 data. The main results show that high test scores are associated with teaching styles that emphasize problem solving and homework. In addition, teachers seem to adapt their optimal teaching style to the 70% least performing students.