Background: In a previous study, information verbally presented as relative risk (e.g. "50% less likely") or qualitative risk (e.g. "significantly less likely") resulted in many more people (66%) choosing a surgical procedure for narrowing or artery in the neck than people presented with absolute risk (e.g. "11% versus 5% over 5 years"), annualized risk (e.g. "2% versus 1% per year for 5 years") and event-free survival (e.g. "95% versus 89% over 5 years") (33%).