Assessment of fatigue among working people: a comparison of six questionnaires, 2003, De Vries et al

Abstract
Aims: To compare the psychometric qualities of six fatigue questionnaires in a sample of working persons.

Methods: Internal consistency and test-retest reliability, content validity, convergent validity, and the dimensionality of the fatigue instruments were explored.

Results: All scales had a satisfactory internal consistency. Furthermore, based on factor analyses and Mokken scale analyses, all scales were unidimensional and appeared to measure an identical construct. The Fatigue Assessment Scale (FAS) had the highest factor loading on the one factor solution obtained in a factor analysis of the total scores of all scales.

Conclusions: All the questionnaires were unidimensional and had good reliability and validity. The FAS was the most promising fatigue measure.

Authors: J De Vries, H J Michielsen, G L Van Heck

Open access full text
https://oem.bmj.com/content/60/suppl_1/i10

 

Questionnaires
The Checklist Individual Strength-20 (CIS-20)15 consists of 20 statements and provides a total fatigue score and scores for four components of fatigue: subjective experience of fatigue (SEF; eight items), reduced concentration (CON; five items), reduced motivation (MOT; four items), and reduced physical activity level (PA; three items). Respondents use a seven point rating scale (1, yes, that is true, to 7, no, that is not true). The reliability of the CIS is good.15 Furthermore, the CIS yielded different scores for CFS patients, multiple sclerosis (MS) patients, and patients with abdominal pain. Moreover, the subscales of the CIS correlated significantly with comparable scales.15 A total score above 76 is considered high. Although the CIS was developed for CFS patients, the questionnaire is claimed to be also appropriate for healthy populations.32 In a number of recent studies among working persons only the total CIS score has been used, while in other investigations one or more subscales have been employed. In the present study, we evaluated the total score as well as subscale scores in order to provide a complete picture concerning the CIS.

The Emotional Exhaustion subscale (EE scale) of the Dutch version of the Maslach Burnout Inventory (MBI25; MBI-NL6), comprises five items, each with a seven point rating scale ranging from 1, never, to 7, always. The scale has well established validity and high internal consistency.6 A score above 2.20 is considered high.

The Energy and Fatigue subscale from the World Health Organisation Quality of Life assessment instrument (EF-WHOQOL-10026; Dutch version33) contains four items. Answers are given on a fivepoint Likert scale (1, never, to 5, always): two positively phrased items using the term “energy” and two negatively phrased featuring the word “fatigue”. This scale has been found to have a good reliability and to have excellent convergent validity.34

The 11 item Fatigue Scale (FS13; Dutch translation35) distinguishes mental fatigue (four items), describing cognitive difficulties, and physical fatigue (seven items). This measure uses a five point rating scale (1, never, to 5, always). It is also possible to calculate a total fatigue score. The scale was found to be both reliable and valid13 and has shown sensitivity to treatment changes.36

The Need for Recovery scale (NRS) from the Questionnaire on Perception and Judgement of Work (VBBA37) is designed to measure the short term effects of a day of work. The 11 items are rated on a dichotomous scale, Yes-No. Reliability and validity of the scale are good.37

The 10 item Fatigue Assessment Scale (FAS29) is a new fatigue scale that was developed in large samples of the Dutch working and general population. The items were selected from an initial item pool consisting of 40 items taken out of existing fatigue questionnaires and represent physical (five items) and mental fatigue (five items). Despite this, based on factor analyses and Mokken Scale analyses, the FAS is considered unidimensional and consequently, only a total score is calculated. The instruction of the FAS is directed at how a person usually feels. The five point rating scale varies from 1, never, to 5, always. Reliability and validity appear to be good. The FAS has a reliability of 0.90 and does not measure emotional stability or depression.29

 

But there's nothing objective to compare them to. It's like comparing "official" weights without having a gold standard, it's irrelevant if they are consistent with one another. They're not compared to anything in real life. In the end it's basically just personal preferences which is "most promising", not a real thing.