Concurrent validity of questions on arm, shoulder and neck symptoms of the RSI QuickScan.
PURPOSE
The objective was to determine the concurrent validity of questions on arm, shoulder and neck symptoms of an Internet-based questionnaire. In addition, the inter-observer reliability of physical examinations by occupational physicians was investigated.


METHODS
A total of 160 employees of a Dutch occupational health service were approached, of which 106 participated. Right after the assessment of arm, shoulder and neck symptoms using a self-administered questionnaire, each participant was examined by two occupational physicians. The presence of symptoms in the past 7 days was compared to the physical examinations. The participation of two occupational physicians allowed us to study also the inter-observer reliability.


RESULTS
Overall, the concurrent validity of the symptom questions of the questionnaire can be defined as poor to moderate with κ values between 0.16 and 0.53. Detecting the presence of symptoms (p(pos)) could be considered as moderately valid with values below 0.60, but the p(neg) shows that the concurrent validity for detecting the absence of arm, shoulder or neck symptoms can be considered sufficient with values above 0.69. The agreement between occupational physicians can, with a few exceptions, be considered as moderate with κ values below 0.60. The agreement was sufficient for detecting the absence of symptoms (p(neg) > 0.7).


CONCLUSIONS
The agreement between the symptom questions of the questionnaire and physical examinations of occupational physicians can be considered as poor to moderate. The results are comparable to what is generally reported in the literature. Future studies should be aimed at gaining more fundamental knowledge about the possible conceptual differences between self-reported symptoms and symptoms assessed using physical examinations. Moreover, it is advisable to improve the inter-observer reliability of physical examinations as applied in the present study.