Evaluation of the Dartmouth COOP charts in a large-scale community survey in the United Kingdom.

BACKGROUND The aim of this study was to gain population norms for the COOP Charts in a large community sample, and to explore the construct validity, and whether the inclusion of the illustrations influences response rates. METHODS A postal survey was carried out using a questionnaire booklet, containing the COOP Charts and a number of other items concerned with lifestyles and illness, sent to 6007 randomly selected subjects over the age of 18 years. Respondents were randomized to receiving the questionnaire booklet with a copy of the COOP Charts including illustrations, or the same booklet but including the COOP items without illustrations. The sample was drawn from the Family Health Services Authority (FHSA) computerized register for Oxfordshire. Outcome measures were scores for the eight dimensions of the COOP Charts. RESULTS The survey achieved an adjusted response rate of 56.72 per cent. There was no difference in response rate or scores on the eight dimensions of the COOP Charts when broken down by those who received the illustrated Charts or simply the items from the measure without illustrations. Normative data for the COOP Charts are reported, broken down by age, sex, social class and whether respondent reported chronic illness or not. CONCLUSION The illustrations included in the original charts do not appear to influence response rates, or responses given to the questions. The evidence suggests that items of the COOP Charts provide a short and comprehensive survey of health status. The normative data provided in this paper may further facilitate their validation and use.