The last 20 years have seen the development of sophisticated techniques for analysing individual data within a hierarchical context and the growing availability of good datasets to which these techniques can be applied. The modelling of pupil performance controlling for prior attainment has led to a type of analysis commonly titled "value-added". Concern for school factors which affect pupil progress has given rise to "school effectiveness" research. This article outlines the history of these linked movements, mainly with reference to England and Wales, but developments in other countries are also outlined. It discusses some of the objections that have been raised, and comments on possible future directions. (Contains 1 figure.)