Although school performance feedback is available in schools all over the world, there is a dearth of information about the use made of feedback and about the effects of its use. This paper presents case study research into the use of school performance feedback and its perceived effects. All schools used the feedback in writing school improvement plans, but the extent of genuine school improvement varied across schools as did the perceived effects of the use of performance feedback. The results highlight various factors which may promote or impede the use of school performance feedback and its effects. (Contains 1 figure and 7 tables.)