Nishiyama C, et al. - Researchers explored if cardiopulmonary resuscitation (CPR) training can increase bystander CPR in the community or the appropriate target number of CPR trainings. For this purpose, they assessed community-wide aggressive dissemination of CPR training, as well as temporal trends in bystander CPR. They provided CPR training (45-minute chest compression–only CPR plus automated external defibrillator use training or the conventional CPR training), targeting 16% of residents, and analyzed data on patients experiencing out-of-hospital cardiac arrest and bystander CPR quality. The chest compression–only CPR training and conventional CPR training were completed by 57,173 (14.7%) and 32,423 (8.3%) residents, respectively, during the study period. No change was evident in the proportion of bystander CPR performed (from 43.3% in 2010 to 42.0% in 2015), but there was a discernable increase in the proportion of high-quality bystander CPR delivery (from 11.7% in 2010 to 20.7% in 2015). There was a link between 1-year increment and high-quality bystander CPR. Overall, the likeliness to perform high-quality CPR was 3.432 times (95% CI, 1.170–10.071) more in bystanders who previously experienced CPR training vs those who did not.