A case study utilising ethnomethodology was undertaken over a two year period. Participant observation was the primary data collection technique. Other data were obtained through the use of surveys, interviews, and unobtrusive techniques, such as use of minutes of meetings, interpretation of some school surveys and school newsletters. The research followed the process of curriculum decision making within the school. Initially, attention was focused on modes of how to develop curricula. From models, attention moved to the processes of curriculum development, in particular, decision making. A relationship is posited between the type of problem and the meaning of participation. Specifically, most decisions involve issues for which there are existing mechanisms for their resolution. The analysis offers some explanation for the incremental nature of school based curriculum development. This analysis derives essentially from the findings on problem solving.