The outcomes of a school improvement programme were measured in 26 primary schools over one year. Authorised pupil and staff absences and staff turnover decreased, and unauthorised pupil absences significantly increased ("p" < 0.05). Fixed-term exclusions significantly decreased ("p" < 0.001). The self-esteem of 316 pupils aged between 4 and 11 before and after programme implementation showed a significant increase ("p" < 0.001). Staff self-esteem also increased significantly ("p" < 0.05) and provided a significant indicator of programme sustainability ("p" < 0.05). Thematic analysis of data from staff interviews demonstrated that the effectiveness of school improvement programmes rested on staff participation in terms of capacity, perceptions of change and stability of the school before programme implementation. These elements were incorporated into a model of school improvement. Goal Attainment Scores were significantly correlated with fidelity of programme participation ("p" < 0.05). Feedback indicated that there was more to school improvement programmes than simply buying one "off the shelf."