The weekend effect has been observed for many conditions. A patient who has an in-hospital cardiac arrest at night or during the weekend is less likely to be successfully resuscitated or survive hospitalization than a patient whose heart stops in the hospital on a weekday. In this large retrospective cohort study, researchers examined trends in in-hospital cardiac arrests over 15 years. Resuscitation and survival to hospital discharge improved nearly 75% overall. The weekend effect persisted, especially in survival to hospital discharge. An accompanying editorial hypothesizes that during nights and weekends fewer specialists are available and fatigue may impair providers' psychomotor skills. A previous PSNet interview highlighted techniques for achieving high reliability at all times of day.