Some effort has been made to develop practical procedures for teachers to evaluate student work on open-ended problem situations. Zehavi, Bruckheimer, and Ben-Zvi (1988) conducted a series of studies with ninth-grade students working on assignment project-open-ended mathematical problems wide in scope, but strictly related to the regular curriculum and to the core mathematics. The use of assignment projects, which included some work in class and some work at home, was found to enhance student mathematical achievement when compared to a control group. In a procedure developed for classifying student responses, the teacher used sequentially ordered hints and noted the first effective hint and its result. It was concluded that the studies produced an organized framework for qualitative evaluation of mathematical activity on open-ended problems. This research exemplifies efforts to investigate not only students' test results but also their thinking processes and the results of that thinking.