Hansen J, Hanewinkel R, Maruska K, et al. The ‘Eigenständig werden’ prevention trial: a cluster randomised controlled study on a school-based life skills programme to prevent substance use onset. BMJ Open 2011;1:e000352. There are two errors in this article. First, there is a line break between “unpleasant” and “emotions” in table 1 (“emotions” should run on from “unpleasant”). Second, in table 4 several errors were inadvertently introduced. The corrected table is below.