Inspired by the successess of last two year's Impact of Science conferences, we have decided with our partner to reconvene the conference in Amsterdam, to discuss measuring and demonstrating the societal impact of science on 4 and 5 June 2015. This conference brings international key players and experts in this field together and help them to understand the possibilities and impossibilities of measuring and demonstrating the societal impact of science has on. During the conference the recent developments in this field will be discussed. Furthermore, ideas on the next steps in measuring the societal impact of science and harmonization of definitions will be exchanged to further professionalize the measurements of the impact of science.