The purpose of this study was to describe and exemplify a model to aid schools in introducing and evaluating new instructional programs. Four basic steps are identified: selecting the curriculum goals, identifying a possible program or programs, evaluating the implementation of the program or programs, and developing and obtaining instruments for the evaluation of goals. This model was used to evaluate two biology courses to assist in making a curriculum decision. Twenty-two 10th grade classes in one high school were studied. Twelve of these classes were using Biological Sciences Curriculum Study (BSCS) materials and the other ten were using a traditional text. Achievement of the students was measured using the Test on Understanding Science, the Cooperative Biology Test, and the Problem Solving Ability Test. Classroom transactions were measured using the Biology Classroom Activity Checklist and three interaction analysis systems. Lesson plans were also collected and examined. It was concluded that, as taught in this high school, the BSCS program more nearly fulfilled the goals that had been set for biology instruction. (EB)