Determining the reliability and convergent validity of a return-to-work status questionnaire

BACKGROUND: In occupational rehabilitation programs, return-to-work is a key outcome measure; however, the studies either used different definitions for return-to-work or do not provide their definition. In order to provide a solution to this issue, we developed a self-report return-to-work measure. OBJECTIVE: We investigated the reliability and validity of a self-report return-to-work questionnaire in a cohort of workers with a work-related injury. METHODS: Two research assistants independently administered the baseline questionnaires and a follow-up questionnaire. The questionnaires contained work-related questions (e.g., currently working, if duties changed) that were used to create a four-category work status measure. Pain-related and a recovery questions were also asked. We obtained loss of earnings data from the compensation board. The short-term reliability and convergent validity were assessed. RESULTS: We recruited 75 workers, and 57 completed the test-re-test baseline questionnaire, and 51 completed the follow-up. The mean age was 45.4 years and 57% were female. The participants had a mixture of musculoskeletal injuries. Most were in the acute stage, but 17% of the participants were injured for more than a year. The short-term reliability of current working status had a kappa value of 0.90. Participants who were not working had higher levels of pain-related disability than those who were working. The kappa value for the agreement between self-reported working status and administrative data on receiving any loss of earnings payment was around 0.65. CONCLUSIONS: Our study provides evidence of reliability and validity for a new return-to-work measure.