A MULTINATIONAL STUDY OF THE FACTORIAL STRUCTURE AND OTHER CHARACTERISTICS OF THE DARTMOUTH COOP FUNCTIONAL HEALTH ASSESSMENT CHARTS WONCA

Background. The 'Dartmouth COOP Functional Health Assessment Charts/WO NCA' constitute a relatively new derived instrument for assessing heal th status that is specifically intended for use in primary care on a w orld-wide basis. It needs further validation in its special area of us e. Objectives. Over a range of countries, social backgrounds and case mixes, our aim was (i) to examine the factorial structure of the instr ument; (ii) to explore how well it was understood; (iii) to check its acceptability; and (iv) to assess the value of the pictures on the cha rts. Methods. The charts themselves, accompanied by a short questionna ire about the charts, were administered to 1719 patients at eight vari ed types of treatment centre in Canada, Japan, Nepal and Spain. The re sponses to the instrument were subjected to standard factor analysis a nd a special Q-type principal components analysis. The responses to di rect questions about the charts were compared with the answers to open -ended questions. Results. Factor analysis suggested a shared factoria l pattern for all sites, with the first two factors accounting for 88. 5% of the variability in correlations between the charts across the si tes. The individual questions were understood by most patients, but a substantial minority did not appear to grasp the underlying purpose of the instrument. The instrument was well accepted. The pictures were c onsidered to be helpful by most respondents, especially those at the N epal sites. The variability in the scores for the individual charts ac ross sites was less than expected and not always in the expected direc tion. Conclusions. The COOP/WONCA system continues to show promise, bu t needs more validation.