Evaluation is a major challenge in the field of health promotion and health education. Since the degree to which a project is planned often guarantees its potential success, the evaluation process should make it possible to answer different questions related to stages of project implementation. The goal of this study was to develop a planning tool to help health professionals and community workers judge the potential success of health education interventions based on the extent to which they are planned and to test the tool in real intervention evaluations. Educational interventions examined in this study were targeted primarily at the promotion and adoption of behaviour reducing the risk of human immunodeficiency virus (HIV) transmission. The conceptual framework of "intervention mapping" served as the basis for developing the tool. Experts were consulted to identify criteria that would make it possible to evaluate the extent to which different stages of the model were accomplished. The tool was tested for reliability. Data from 123 projects were then collected and analyzed. The process for the development of the tool made it possible to identify 40 planning criteria, broken down into the 19 tasks of intervention mapping model. Reliability test results were highly satisfactory. The overall average score for project planning was 12.7 out of 40. The degree to which different stages were planned varied considerably. For example, only 15% of projects had developed their objective matrices properly, whereas 80% were assured proper support for their implementation. Thirty-nine percent of the projects were satisfactorily available for evaluation. This exercise made it possible to construct an interesting tool for identifying strengths and weaknesses of intervention planning. Various promoters might find this tool useful for increasing the potential success of their initiatives.