In order to develop a scientific theory of curriculum, a method for measuring the curriculum-related planning activity of teachers is proposed. This choice of focus is based on the assumption that a logical connection can be made between the level of teacher planning, the quality of the resulting actions, and the corresponding goal attainment by students. The level of planning activity is defined in terms of the quantity of decision making, the degree of involvement of other persons in the decision process, and the degree of formality of materials used in decision making. A self-report form is recommended, supplemented with the use of a multiple matrix sampling design. The method was devised to reduce the ambiguity of language used to describe curriculum decisions, the difficulty of retrospective recall over long periods of time, and the confusion of real versus psychological constructs. The sampling design and examples of self-report items are included. The self-reporting form focuses on decisions related to the planning stages of teaching, such as topics for individual study, classroom interest centers, and lesson plans. The items include general items, followed by source of information and types of decisions. (Author/JAC)