Rural development practices are found throughout Europe and cover a wide range of different types of activity. At first sight there does not seem to be much similarity between these different practices. This paper presents the results of a comparative analysis of some 30 cases of rural development from the different tracts of European countryside studied in the first phase of the impact research programme. The paper summarizes several of the communalities that were revealed in the analysis and goes on to consider differences that may be relevant to policy, especially in relation to the levels of socio-economic impact generated by rural development practices in terms of extra income and employment. By means of clustering sets of cases according to regional and farm level impact data, a number of underlying factors in successful rural development and its translation into socio-economic impacts are identified. Important factors relate the dissemination of activities by integrating new participants and repetition by others, the unleashing of synergy effects within clusters of compatible and mutually reinforcing rural development activities,and the construction of regional ‘protected spaces’ within the dominant technological regime that favour rural development.