RELIABILITY AND VALIDITY TESTING OF THE MICHIGAN HAND OUTCOMES QUESTIONNAIRE

In this study, psychometric principles were used to develop an outcome s questionnaire capable of measuring health state domains important to patients with hand disorders. These domains were hypothesized to incl ude (1) overall hand function, (2) activities of daily living (ADL), ( 3) pain, (4) work performance, (5) aesthetics, and (6) patient satisfa ction with hand function. An initial pool of 100 questions was pilot-t ested for clarity in 20 patients; following factor analysis, the numbe r of questions was reduced to a 37-item Michigan Hand Outcomes Questio nnaire (MHQ). The MHQ, along with the Short Form-12, a generic health status outcomes questionnaire, was then administered to 200 consecutiv e patients at a university-based hand surgery clinic and was subjected to reliability and validity testing. The mean time required to comple te the questionnaire was 10 minutes (range, 7-20 minutes). Factor anal ysis supported the 6 hypothesized scales. Test-retest reliability usin g Spearman's correlation demonstrated substantial agreement, ranging f rom 0.81 for the aesthetics scale to 0.97 for the ADL scale. In testin g for internal consistency, Cronbach's alphas ranged from 0.86 for the pain scale to 0.97 for the ADL scale (values >0.7 for Cronbach's alph a are considered a good internal consistency). Correlation between sca les gave evidence of construct validity. In comparing similar scales i n the MHQ and the Short Form-12, a moderate correlation (range, 0.54-0 .79) for the ADL, work performance, and pain scales was found. In eval uating the discriminate validity of the aesthetics scale, a significan t difference (p =.0012) was found between the aesthetics scores for pa tients with carpal tunnel syndrome and patients with rheumatoid arthri tis. The MHQ is a reliable and valid instrument for measuring hand out comes. It can be used in a clinic setting with minimal burden to patie nts. The questions in the MHQ have undergone rigorous psychometric tes ting, and the MHQ is a promising instrument for evaluation of outcomes following hand surgery. (1 Hand Surg 1998;23A:575-587. Copyright (C) 1998 by the American Society for Surgery of the Hand.)