Prior research has estimated that 6% of patients receiving medical care experience preventable harm. This study compared the incidence and preventability of adverse events in older patients over an eight-year period (2008-2016). Findings indicate that while the incidence of adverse events declined across the time period, the preventability of the events did not. The authors posit that this could be due to crowding or increasing care complexity due to age, frailty, comorbidities, or polypharmacy.