The meta analyses of Active Labor Market Programs jointly with Andrea Weber (CEU) and 2021 Nobel laureate David Card (UC Berkeley) can be found here: Economic Journal 2010 and here: Journal of the European Economic Association 2018 An earlier study specifically on Europe that had its origin in a research project initiated by the European Commission DG Employment can be found here. The comprehensive evaluation of the Hartz labor market reforms was a unique public policy evaluation in the 2000s which involved many actors from government and research institutions; a paper with Lena Jacobi summarizes the main findings. From a researcher's perspective, it is particularly inspiring when policy impact evaluations can be implemented using natural experiments such as RDD -- one example was the evaluation of the new parental leave for the German federal government, see the papers with Marcus Tamm here, and with Sebastian Schmitz for the longer-term effects.