Effecten van een didactische interventie bij het leren in kleine groepen in de basisvorming.

This article reports on two intervention studies into the effects of a training in the use of social and/or cognitive strategies on the learning outcomes of students in secondary mathematics education. Special attention is given to differential effects for high- and low-achieving students. The studies were addressed to the following research question: What are the general and differential effects of training in the use of social and/or cognitive strategies on the results of learning in secondary mathematics? In the first study three instructional programs for co-operative learning were compared: (i) an experimental program with special instruction in the use of social strategies, (ii) an experimental program with special instruction in the use of cognitive strategies, and (iii) a control program without training in either cognitive or social strategies. The programs were identical with respect to mathematical content and general instructional settings (a combination of whole-class instruction, working in co-operative groups and individual work). The research was conducted in two schools for secondary education and in 21 classes, involving a total of 511 students. The design was a pretest-posttest control group design, using two experimental groups and one control group. The data were analysed from a multi-level perspective. The outcomes of the investigation clearly show the effects of the intervention. Teaching cognitive and social strategies has the expected, positive effects. In addition to this main effect, a compensatory effect for the low-achieving students was found. The low-achieving students in the experimental conditions outperformed their counterparts in the control group.In the experimental program of the second study students were trained in cognitive strategies and social strategies. To put it differently, the training involved mathematical problem solving and strategies for effective group work: social and cognitive strategies were integrated. As in the first study, students in the control group did not receive any strategy instruction. In general, the outcomes of the second study confirmed the positive results of the first study, however it turned out that low achieving students in the experimental program had about the same learning gains as their counterparts in the control program. The differences in outcomes concerning the low achieving students are discussed in detai