This report introduces the practical problems related to formative evaluation of educational programmes in avoiding non‐functional designs and also keeping data gathering and analysis simple and utilitarian. A rationale for a systems‐based approach is presented and illustrated using a technique called Branching Diagram Analysis (BDA). Following a discussion of an illustration of the technique, three cases are presented of evaluations of a school improvement project, a doctoral seminar, and three different staff development‐training programmes. For each illustrative case the analysis, interpretations, and findings are presented to help readers understand practical uses of such evaluation procedures.