Confirmatory factor analysis of the Michigan Hand Questionnaire.

Background: When the Michigan Hand Questionnaire (MHQ) was originally developed, an exploratory factor analysis (EFA) was used to reduce the originally large number of generated items to the 63 items currently present on the questionnaire. Confirmation of the implied factor model of the existing MHQ has never been performed. The objective of this study was to confirm the factor model used to create the existing MHQ, and to possibly shorten the existing MHQ using factor analysis.

Methods: Patients attending the Plastic Surgery Clinic at the QEII Health Sciences Centre with a hand complaint were asked to complete the MHQ. Confirmatory factor analysis was performed to explore the implied factor structure of the original EFA and to examine the interplay between the MHQ subscales. Further item-reduction was performed using clinically guided decisions as well as factor analysis-guided statistics.

Results: Initial confirmatory factor analysis showed that original EFA model does not optimally explain the relationships between items in the existing MHQ and their corresponding factors. Our abbreviated model of the MHQ consists of 23 items, and performed more favorably in all goodness-of-fit parameters than the original 63-item questionnaire.

Conclusions: The factor model of the existing MHQ does not fully take advantage of the relationship between items in the MHQ and the proposed factors. This study proposes a shortened version of the MHQ that more accurately reflects hand health as well as a factor-based interpretation of the subscales that takes interdependent relationships into account.