Occup Environ Med 2000;57:353–357 353
Fatigue among working people: validity of a questionnaire measure
Anna J H M Beurskens, Ute Bültmann, IJmert Kant, Jan H M M Vercoulen, Gijs Bleijenberg, Gerard M H Swaen
Abstract Objectives—To evaluate the validity of the checklist individual strength questionnaire (CIS) in theworking population. This 20 item self reported questionnaire has often been used in patients with chronic fatigue. To date, no research has focused on the validity of the CIS in occupational groups. Methods—To evaluate the discriminant validity the CIS was ﬁlled out by ﬁve groups of employees with expected diVerences in fatigue. The convergent validity was evaluated by comparing the results of theCIS with the results of three related measures: measured unidimensional fatigue, burnout, and need for recovery. Results—The CIS was able to discriminate between fatigued and non-fatigued employees in occupational groups. The expected agreement between the results of the CIS and related measures was conﬁrmed. Conclusions—The CIS seems to be an appropriate instrument for measuring fatigue in theworking population.
(Occup Environ Med 2000;57:353–357) Keywords: fatigue; occupational groups; measurement
Department of Epidemiology, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands A J H M Beurskens U Bültmann IJ Kant G M H Swaen Department of Medical Psychology, University Hospital Nijmegen, The Netherlands J H M M Vercoulen G Bleijenberg
Correspondence to: Dr ABeurskens ajhm.Beurskens@ epid.unimaas.nl Accepted 30 December 1999
Fatigue at work is a normal everyday experience. However, in the case of severe fatigue it may aVect the person’s performance in the occupational as well as the home setting. Moreover, severe long term fatigue may lead to sick leave and work disability. In The Netherlands about one in every three recipients of work disabilitybeneﬁt is classiﬁed as occupationally disabled on mental grounds.1 They have an “exogenous reaction”,2 which is the oYcial diagnosis that includes chronic job stress and burnout—that is, a mental state closely related to mental fatigue. In 1996 a large scale national concerted research action on fatigue at work was initiated in The Netherlands. This multidisciplinary research programme includespsychological and medical research and is supported by grants from The Netherlands Organisation for Scientiﬁc Research (NWO), universities, occupational health services, private research institutes, trade unions, and business.3 Within the research programme fatigue is deﬁned as: “The change in the psychological control mechanism that regulates task behaviour, resulting from preliminary mental and/orphysical eVorts which have become bother-
some to such an extent that the individual is no longer able to adequately meet the demands that the job requires on his or her mental functioning, or that the individual is able to meet these demands only at the cost of increasing mental eVort and the surmounting of psychic resistance”.3 We see fatigue, in line with Lewis and Wessely,4 as a subjectivesensation with emotional, behavioural, and cognitive components. There is an essential diVerence between acute fatigue and long term fatigue. Acute fatigue is characterised by reversibility, task speciﬁcity, and the functional use of compensation mechanisms. Acute fatigue is a normal phenomenon that disappears after a period of rest, when tasks are switched, or when particular strategies are used—forexample, working at a slower pace. By contrast, long term fatigue is irreversible, not task speciﬁc, and the compensation mechanisms that were useful in reducing acute fatigue are no longer eVective. To gain more insight in the aetiology and prognosis of long term fatigue at work one of the research programmes within the national concerted research action studies is the epidemiology of long term...