Reliability of Nonorganic Sign Testing
Waddell et al defined illness behavior that can be relevant to both the development and the maintenance of chronic pain. They developed a screening tool to screen for nonorganic signs that they feel indicate emotional or psychological distress. This can be beneficial in terms of further assessment and treatment. The Waddell score consists of eight standardized physical nonorganic maneuvers, divided into five categories. The overall score is positive if at least three of the categories are scored positively.

Some clinicians have criticized these signs even though there is increasing evidence that these nonorganic signs are associated with poorer outcomes and greater disability. The authors of this study agree with others that there is limited literature, and conflicting outcomes regarding the reliability of nonorganic signs.

The authors recruited 126 subjects with chronic low back pain. Two examiners were involved in testing the subjects for nonorganic signs two times over the course of the study. The prevalence of positive signs and categories varied from 14 percent to 49 percent, and was 36 percent for the Waddell score.

The authors concluded that the Waddell score when used by the trained observers in their study demonstrated moderate interobserver reliability. The intraobserver reliability was good.
References
A. Apeldoorn et al. The Reliability of Nonorganic Sign-testing and the Waddell Score in Patients with Chronic Low Back Pain. SPINE. Volume 33. Number 7. Pp. 821-826.