Clinical Frailty Scale

The Clinical Frailty Scale (CFS) was introduced in the second clinical examination of the Canadian Study of Health and Aging (CSHA) as a way to summarize the overall level of fitness or frailty of an older adult after they had been evaluated by an experienced clinician (Rockwood et al., 2005).

Although introduced as a means of summarizing a multidimensional assessment in an epidemiological setting, the CFS quickly evolved for clinical use, and has been widely taken up as a judgement-based tool to screen for frailty and to broadly stratify degrees of fitness and frailty. It is not a questionnaire, but a way to summarize information from a clinical encounter with an older person, in a context in which it is useful to screen for and roughly quantify an individual’s overall health status.

The highest grade of the CFS (level 7) as published in 2005, incorporated both severe frailty and terminal illness. Later, it became evident that we needed to distinguish between identifiable groups who were otherwise lumped together in the original scale – severely frail, very severely frail and terminally ill - as clinically distinct groups who required distinctive care plans. Therefore, in 2007 the CFS was expanded from a 7-point scale to the present 9-point scale, and it has been used extensively in that format. We published on the predictive validity of the 9-point CFS in 2020 (Pulok et al., 2020). 

In 2020 the CFS was further revised (version 2.0) with minor clarifying edits to the level descriptions and their corresponding labels. Most notably, CFS level 2 changed from "Well" to "Fit", level 4 from "Vulnerable" to "Living with Very Mild Frailty", and levels 5-8 were restated as "Living with..." mild, moderate, severe, and very severe frailty, respectively (Rockwood & Theou, 2020). 

Please refer to the CFS Guidance and Training section of this website for more information and resources about using the Clinical Frailty Scale. For novice CFS raters, we developed a classification tree to assist with CFS scoring. 


Rockwood K, Song X, MacKnight C, Bergman H, Hogan DB, McDowell I, Mitnitski A. A global clinical measure of fitness and frailty in elderly people. CMAJ. 2005;173(5):489-495.

Pulok MH, Theou O, van der Valk AM, Rockwood K. The role of illness acuity on the association between frailty and mortality in emergency department patients referred to internal medicine. Age Ageing. 2020;49(6):1071-1079.  

Rockwood K, Theou O. Using the Clinical Frailty Scale in Allocating Scarce Health Care Resources. Can Geriatr J. 2020:23(3):210-215.

Permission for Use

To guard against copyright infringement or unlicensed commercial use, we ask all potential users to complete a Permission for Use Agreement. Agreements are reviewed by the Industry Liaison Office at Dalhousie University to determine whether a license agreement is required. Requests for non-commercial educational, clinical and research use, as well as for reprint usually do not require a license agreement.

As a result of its worldwide uptake, the Clinical Frailty Scale is now available in a number of languages (see CFS Translations).