The assessment for learning framework in education has become big business: huge quantities of time, money and energy have been invested in England, Wales and more recently the USA. This article shows that the assessment for learning theory is inefficient and often contradictory. Black and Wiliam's earlier work provides much of the theoretical rationale for this paradigm and evaluating three papers will serve to illustrate how existing anomalies arose. Their work has been little challenged, partly because of their seniority and position, and the respect accorded to them in the academic community, and also because of the undoubted contribution which their work has made to providing an ethical and practical working philosophy of institutional learning which prioritises formative assessment and, therefore, learning over assessing. However, respect for their achievements also includes building on and improving their work.