Table 2.

Items used in our assessment of construct validity. Selection is based on the similarity of construct with that of the NFR Scale.

English Translation	Scoring Values
How many days in the last four weeks has muscle or joint pain inhibited you? (e.g., affected you daily routine or activities)	0–28 days
How physically demanding do you normally perceive your working situation? [27]	0–10 numerical ratings scale. 0 being not demanding; 10 being maximally demanding
How do you rate your overall health? [24]	5 point likert scale 1 being very poor; 5 being excellent
How do you rate your current work ability in relation to the psychological/cognitive demands of your work? [26]	5 point likert scale 1 being very poor; 5 being excellent
How do you rate your current work ability in relation to the physical demands of you work? [26]	5 point likert scale 1 being very poor; 5 being excellent
How do you rate your current work ability? [26]	0–10 numerical ratings scale. 0 being unable to work; 10 being work ability at it’s best
Do you wake up fresh and recovered? [25]	6 point likert scale 1 being at no time; 6 being all the time
Do you feel calm and relaxed? [25]	6 point likert scale 1 being at no time; 6 being all the time