A Cost Benefit Analysis Model to describe the perception and use of Activities in self-instructional texts

The results of a qualitative study, that explored students perception and use of Activities in self-instructional texts, are described, illustrated and analysed. The emergent constructs, identified by means of interview, questionnaire and self-recorded audio-tape, are interpreted in the context of a Cost Benefit Analysis Model. The findings challenge the dominant model of Mathemagenic Devices and of experimental research into adjunct questions; it offers a methodology and a framework by which students’ perceptions and use of Activities can be explored.