The present paper argues that recent research on public sector reforms offers few contributions to the body of knowledge on this topic because it adds little to the conclusions drawn during the first generation of research in this area. Although these later studies have often been context-specific and have explored the details of the process of change in some depth, it is rather difficult to compare their results or to make reasoned judgements of the comprehensiveness and centrality of the analysed change. Although most public sector reforms that affect hospitals, schools or social services are initiated and designed by national governments, individual case studies of local administrations often fail to capture the generic traits of nationwide reforms. However, public sector change cannot be approached as if it comprises collections of nominally independent local events. The present paper argues for two new approaches to the study of public sector change: (i) the systematic categorization of the different forms of governmental intervention under study and (ii) analysis of the ways in which these forms of intervention are linked and interact. Based on extensive empirical research, this paper suggests a generic classification of these forms of intervention that can be used in empirical research on comprehensive public sector change. Consequently, five interventions in public sector organizations are suggested, namely political intervention, intervention by laws and regulations, intervention by audit and inspection, intervention by management and intervention by rationalizing professional practice. The model is particularly well suited to the longitudinal analysis of complex public sector reforms. This approach provides a conceptual tool to distinguish between interventions based on different forms of knowledge and to investigate how they are linked to each other vertically and horizontally. We demonstrate the usefulness of the model by analysing two empirical examples of reforms in which a variety of interventions were imposed at the local level, through legislation as well as a spectrum of voluntary measures proposed by government agencies, by national associations for local and regional councils and by other national or regional actors.