To identify the incidence of self-reported harmful adverse events in the health care of community-dwelling adults, and to examine attitudes about safety in the health system.

Cross-sectional, population-based survey.

Analysis of data from 3522 adults participating in Stage 2 of the North West Adelaide Health Study, who were surveyed in 2004 and 2005.

Self-reported adverse events causing harm in the past year; attitudes to safety in health care, including adequacy of current measures for preventing adverse events, and the effect of groups like patients themselves, doctors and governments on patient safety.

The annual incidence of self-reported harmful adverse events was 4.2%. The main types were medication error (45.5%) and misdiagnosis or wrong treatment (25.6%). Multiple logistic regression showed that self-reported harmful adverse events were more likely in people who had been hospitalised in the past 12 months (odds ratio [OR], 2.5; 95% CI, 1.9–3.4), those who had low annual income (< $12 000), those who completed higher education to the level of Bachelor degree or higher (OR, 3.0; 95% CI, 1.0–9.4), and those who had some level of dissatisfaction with their recent health care; and less likely in those more risk-averse rather than those with a tendency to risk-taking behaviour (OR, 0.6; 95% CI, 0.4–0.9). People were more likely to believe that individual health care professionals had a positive effect on safety than professional groups or government, and that more resources were the key to improving the safety of health care.

We found an incidence of self-reported harmful adverse events that was significantly lower than that found by a 2002 Australian survey (4.2% v 6.5%; P = 0.009). Better communication to help patients acquire more realistic risk perception may help reduce harm. Better communication could also increase public advocacy for systems improvement in safety to counter persisting community beliefs that individual action alone can redress the situation.