Illinois-funded Project IMPACT was designed to identify and develop procedures for complying with the impact requirement of Public Law 94-482, with regard to the effect of vocational education research and development on vocational education programs. The study addressed itself to three problem areas: (1) how to define impact, (2) how to assess impact, and (3) how to show a cause-and-effect relationship between project activities and changes in vocational education teaching-learning situations. The project also investigated how to predict the probability of impact, and how to manage ongoing contracts to increase impact probability. In this first volume of the phase 1 reports, Project IMPACT is defined, principles of assessing impact are determined, and methods of study are decided through a review of literature and an analysis of case study methods. The review of literature on planned change and impact assessment showed that evidence of impact may be direct or indirect; that the time between cause and effect of impact is longer for intellectual products than for tangible products, and that it is desirable to assess impact of a project at the school district level rather than at higher administrative levels. It also showed that numerous characteristics which are associated with high versus low impact have been identified and that the degree to which these characteristics are present or absent may be useful in predicting actual impact. Through the analysis of case study methods, procedures for assessing impact of vocational education projects through case studies were established. These procedures were followed in the case studies in volumes 2-8 of this series (see note). (KC)