New models of interprofessional working are continuously being proposed to address the burgeoning health and social care needs of older people with complex and long-term health conditions. Evaluations of the effectiveness of these models tend to focus on process measures rather than outcomes for the older person. This discussion paper argues that the concept of frailty, and measures based on it, may provide a more user-centred tool for the evaluation of interprofessional services - a tool that cuts across unidisciplinary preoccupations and definitions of effectiveness. Numerous frailty scales have been developed for case identification and stratification of risk of adverse outcomes. We suggest that they may also be particularly suitable for evaluating the effectiveness of interprofessional working with community-dwelling older people. Several exemplars of frailty scales that might serve this purpose are identified, and their potential contributions and limitations are discussed. Further work is required to establish which is the most suitable scales for this application. The development of an appropriate frailty scale could provide an opportunity for interprofessional debate about the forms of care and treatment that should be prioritised to improve the health and well-being of this population.