VALIDATION DATA

The subscales have a high degree of internal consistency, as illustrated by the high Cronbach α ranging from 0.85 to 0.88.

High test-retest reliability, ranging from 0.74 to 0.92.

An expert panel composed of podiatric physicians, measurement experts, and potential respondents was used to rate questions on content coverage and relevance as well as technical factors, and a mean rating was assigned. On the basis of these ratings, 19 questions were eliminated. The remaining questions were administered to 225 subjects who presented to the Queensland University of Technology podiatric clinic for treatment.

During the development, a principal component analysis with scree test was performed and indicated that only four factors (pain, function, footwear, and general foot health) could be extracted. The four factors were rotated to simple structure using the direct oblimin technique and 12 additional items were omitted based on item factor loadings of less than 0.7.

There is not a gold standard for foot health status, but additional construct validation was provided by classifying foot diseases (minor pathology, acute disease, and morphological problems) and assessing the ability of the FHSQ to discriminate between different types of foot pathology. Minor foot complaints tended to produce higher scores in the pain, function, and general foot health scales. By contrast, more severe foot problems (such as neuromas, plantar fasciitis, and tarsal inflammation) seemingly produced more impairment and disability in terms of pain and function (F[2,92] = 32.07, P = .00; and F[2,96] = 25.03, P = .00, respectively). Also, after adjusting for the effects of age and sex, subjects with foot-morphology problems (cavus foot types, hammer toes, interdigital corns, and bunion development) scored significantly worse than any other group in the footwear domain (F[2,95] = 4.962, P = .009).