Drug policy shortlist: https://www.euda.europa.eu/activities/scientific-award-shortlist-2016_en

Mason, T., Sutton, M., Whittaker, W., McSweeney, T., Millar, T., Donmall, M., Jones, A., Pierce, M. (2015), The impact of paying treatment providers for outcomes: difference-in-differences analysis of the ‘payment by results for drugs recovery' pilot’. Addiction, 110: 1120–1128.