The Education Action Zone programme in Gauteng province, South Africa, has been widely seen as a very successful school improvement initiative, with particular significance as it represents a unique model of top-down, bureaucratic accountability as a vehicle for turning- around dysfunctional secondary schools. In this article I evaluate the impact of the initiative through an analysis of the senior secondary examination results for 1999-2002, in the 70 schools involved in the programme. It was found that the EAZ schools made significant gains in the overall pass rate, university pass rates, number of "A" symbols , and average mark. The results of comparative analysis confirmed the overall success of the programme. However an alternative explanation raised questions about the mechanisms of improvement by uncovering a relationship between gains in examination results and learner exclusion.