Personal alarms or Personal Response Systems (PRSs) are electronic systems designed to enable frail older people and people with disabilities living at home to summon help in an emergency. The demand for government subsidised PRSs in Victoria (called Personal Alert Victoria) currently exceeds supply (Department of Human Services, 1998) but until now there has been no consistently applied method to ensure that those at highest risk had access to the service. Instruments to aid assessment and determining relative priority for receiving a PRS were developed for the Victorian Department of Human Services (DHS). The development of the instruments was largely informed by the published literature on PRSs and falls risk factors. Three major areas were identified as important in assessing for relative priority to receive a PRS: the client?s assessed risk of being involved in a critical incident requiring immediate assistance, such as a fall; the availability of alternative means of accessing immediate assistance; and the expected impact that a PRS would have on the client?s and/or carer?s wellbeing and their ability to engage in important activities. The process for selecting the items used to determine need in each of these key areas is described, as is the recommended method for determining relative priority. The process for assessing clients to receive a PRS is outlined, emphasising that a PRS is one potential service outcome of an assessment of need.