Assessment of the COOP charts with and without pictures in a Swiss population

Objectives: This study aimed to assess the validity of COOP charts in a gen eral population sample, to examine whether illustrations contribute to inst rument validity, and to establish general population norms. Methods: A gene ral population mail survey was conducted among 20-79 years old residents of the Swiss canton of Vaud. Participants were invited to complete COOP chart s, the SF-36 Health Survey; they also provided data on health service use i n the previous month. Two thirds of the respondents received standard COOP charts, the rest received charts without illustrations. Results: Overall 12 50 persons responded (54%). The presence of illustrations did not affect sc ore distributions, except that the illustrated 'physical fitness' chart dre w greater non-response (10 vs. 3%, p < 0.001). Validity tests were similar for illustrated and picture-less charts. Factor analysis yielded two princi pal components, corresponding to physical and mental health. Six COOP chart s showed strong and nearly linear relationships with corresponding SF36 sco res (all p < 0.001), demonstrating concurrent validity. Similarly, most COO P charts were associated with the use of medical services in the past month . Only the chart on 'social support' partly deviated from construct validit y hypotheses. Population norms revealed a generally lower health status in women and an age-related decline in physical health. Conclusions: COOP char ts can be used to assess the health status of a general population. Their v alidity is good, with the possible exception of the 'social support' chart. The illustrations do not affect the properties of this instrument.