The objective of this project is to determine the prevalence, risk factors, clinical consequences and costs of high risk prescribing in older people. Given that older people are the most likely to be prescribed medications yet the most likely to be harmed by their medications, this study will provide an important evidence base for the quality use of medications in Australia. Please note that the study population for this project will include all participants aged 45 years and over, with a main focus on participants aged 60 years and over. This will allow us to explore age-related trends in high risk prescribing across a broad age range. The grant application restricts the focus to 60 and over to facilitate consideration by the NHMRC Geriatrics panel.