AbstractThere is evidence that many schools aredifferentially effectivein that they promote with different effectiveness the academic attainments of different groups of pupils, divided by such characteristics as prior academic attainments, socio-economic background and so on. Awareness of the extent and direction of a school's differential effectiveness is important. Measures of overall performance of a differentially effective school can be misleading and targets seeking to improve the overall performance of such a school may not address its underlying inadequacies in raising the attainments of specific groups of pupils. This paper develops a data envelopment analysis based method for setting targets for diffentially effective schools to enable them to alter the bias of their differential effectiveness. The method also identifies role model schools which a differentially effective school can emulate in seeking to redress the imbalances in its effectiveness.