The digital transformation in the public sector is steadily advancing. An important aspect in this process in many countries is the provision of administrative data as Open Government Data (OGD), since public organisations often produce and collect large amounts of data and are required to follow high standards of transparency at the same time. Increasingly, however, the question arises how OGD can have a positive impact on the common good beyond transparency and how this could be promoted. In this discursive article, we therefore look at the prerequisites and success factors for generating impact through OGD in three steps. First, we discuss how OGD can be optimally published so that they can easily be found, read and processed. Second, we discuss what impact means in relation to OGD, which types of impact can be distinguished and which mechanisms potentially lead to such effects. Third, we focus specifically on the instrument of innovation contests, such as hackathons, as a possible key to success. Since public organisations are participating more and more in such events, we provide some specific recommendations for preparing and participating in these somewhat special competitions before drawing a conclusion.