Dear all, Many dataset are results of  complex survey design (e.g. uneven probability of selection). In this dataset each observation is associated with a different sampling weights. These weights are different than CEM  weights desxribed in j.mp/CEMweights. Sample weights are used to compute sample (weighted) statistics that are representative of  population statistic. My question is, in case of complex survey design, does CEM allow to compute ATT for the sample only or also for the population ? is any adjustment needed ? my tentative answer is yes and CEM weight should be combined with sample weighting but I would appreciate your advise. kind regards Cesare Cesare A. F. Riillo, PhD STATEC Research National Institute of statistics and economic studies of the Grand Duchy of Luxembourg. 13, rue Erasme L-1468 Luxembourg www.statec.lu Postal address: B.P. 304 L-2013 Luxembourg