This retrospective study in the Netherlands encompasses three national major adverse event studies. These authors previously reported that the adverse event rate in the Netherlands had increased between 2004 and 2008. In this current study, there was no change in overall adverse event rates in 2011/2012 compared to 2008, while preventable adverse events were markedly reduced by 45%. Following multiple adjustments, this decrease was still evident (30%), though no longer met statistical significance (p=0.10). The decreased harms were seen in areas addressed by national safety programs implemented during this time, suggesting a positive effect from these efforts. A related editorial by Charles Vincent and Rene Amalberti discusses the expanding scope of patient safety as more medical harms become regarded as preventable. A second editorial by two of the journal's editors discusses the degree to which the nonsignificant reduction in preventable adverse events plausibly represents improvements from a national patient safety program in the Netherlands. It also advances the idea that the results highlight some of the limitations of adverse events as a measure of progress in patient safety, a point also made in the editorial by Vincent and Almaberti.