Validity of the patient-focused wrist outcome instrument: do impairments represent functional ability?

The development of outcome instruments has been reported to be a long process, often taking years to complete. In a previous article, we reported on the rationale behind the construction of a new wrist outcome instrument that assesses, from the wrist-injured individual's perspective, their ability to perform activities of daily living following a wrist disorder. Content validity and test-retest reliability of the wrist outcome instrument also was demonstrated. Here we report on the results of the assessment of other aspects of validity, specifically construct validity of the wrist outcome instrument and the ability of the instrument to detect change over time. We evaluated these psychometric properties against frequently used clinical tests that assess impairments and thus report on the relationship between the ability to perform activities of daily living and impairment measures.