Knowledge of results
An important question was whether scores would be improved more if direct teaching was given either before or after the question was asked. The answer in both cases was (broadly) yes. Using instructional films, Michael and Maccoby split groups into two halves. Half the students were given material which required active, explicit responses. After a pause, they were told the correct answer. The other half was not given feedback. Instructional time was identical. The result showed a "slight but significant gain" for the active-response procedure without feedback, but more gain when feedback was provided. The experimenters later described this as "KCR" rather than "feedback". Research on the active response itself is summarised in p614. Later discussion of experiments like these suggested that the results might be due to practice rather than feedback. Undoubtedly, the set-up had given extra practice on the questions as well as knowledge of results. In technical terms, the experiments had confounded the two factors.