What Do the OMERACT Shoulder Core Set Candidate Instruments Measure? An Analysis Using the Refined International Classification of Functioning, Disability, and Health Linking Rules.

Two of 6 pain instruments include constructs other than pain. Within the physical function/activity domain, 2 candidate instruments matched the domain, 3 included additional content, and 2 included meaningful concepts in the response options, suggesting that they should be omitted as candidate instruments. The analyses show that the content in most existing instruments of shoulder pain and functioning extends across core set domains.