The CSHA is a representative 5-year prospective cohort study. Its first stage of investigation (CSHA-1) began in 1991 with 10 263 people aged 65 years and older, recruited with the aim of describing the epidemiology of cognitive impairment and other important health issues in elderly Canadians.,, From the clinical examinations we did within this cohort, we developed the rules-based frailty definition and the Frailty Index, a measure of frailty obtained by counting various clinical deficits (). Afterward, we also developed CSHA scales for function and overall clinical frailty, with the goal of creating tools that could stratify elderly patients as to their relative degree of vulnerability (i.e., their risks of death and of entry into an institutional facility) with simple clinical descriptors. We defined the Clinical Frailty Scale using the terminology of Streiner and Norman. Rooted in our theoretical model of fitness and frailty and the importance of function (which we reported in earlier investigations), our Clinical Frailty Scale () ranges from 1 (robust health) to 7 (complete functional dependence on others).