The Open Data Challenge Series was a series of seven challenge prizes run by Nesta and the Open Data Initiative between 2013 and 2015. Businesses, start-ups and individuals were invited to develop innovative solutions to social issues using open data. The challenges centred on a number of themes (Crime and Justice, Education, Energy and Environment, Housing, Food, Heritage and Culture, and Jobs) and participants competed for an equity free cash prize of £40-50,000. At the end of the Series, Icarus was asked to undertake research to pull out the lessons about running a programme of this nature and to inform the development of future Challenge Prizes. The research methods we employed included the following: interviews, online surveys, desk based research and virtual focus groups. Our report can be found here: