Older people with frailty are more vulnerable to sudden declines in health in response to seemingly small trigger events such as drug side effects or overmedication. Identifying older people in the community with frailty offers an opportunity to prevent or delay these adverse events. This study takes advantage of New Zealand’s world-leading comprehensive assessment system for older people (the interRAI). In partnership with Canterbury DHB we will develop and trial a measure of frailty within the interRAI to guide better medication treatment plans and enhance clinical management. We will compare possible measures statistically using existing data and then evaluate the impact of utilising the interRAI to identify frailty and target medication reviews in a stratified randomised-controlled trial. The research may offer a specific workable improvement to the national interRAI assessment system to help prevent unnecessary medication complications and hospitalisations for older people with frailty.