What are frailty instruments for?

This is the authors' abstract. We don't add key points for this paper.

Frailty is measured to understand its nature and biology, to aid diagnosis and care planning, to measure outcomes and to stratify risk. Such goals oblige two types of frailty measures - for screening and for assessment - and recognition that not all measures will serve all purposes. When the goal is broad identification of people at risk, a dichotomised approach (frailty is present or absent ) is appropriate. If, however, the degree of risk varies, strategies to test grades of frailty will be required. Frailty measures should be implemented and evaluated in relation to the goal for their use.