Most of the literature on the instructional effects of operationally defining the objectives of a curriculum before implementation has been based on a logical, rather than an empirical, analysis of the instructional process. A model procedure was developed and used to examine empirically the contribution of the cognitive objectives of an instructional system to the instructional process within an operational middle school setting (grades 5-8). When valid tests were constructed, teachers were taught toward and students mastered the cognitive behaviors stated in the prespecified objectives of the curriculum. Although this relationship held for individual classes, comparison across classes for a grade level indicated that teachers had considerable instructional freedom when implementing the curriculum within the classroom. (Author)