Table 5.

Fatigue item variable name, content, relevance indices, and short form membership (denoted with an ‘x’)

PROMIS variable name	Item content	RI-CL44	RI-MS20	PROMIS-FatigueSFv1.0	PROMIS-FatigueMS
FATEXP6	How often did you feel tired even when you had not done anything?	0.92	4.39		X
FATIMP3	How often did you have to push yourself to get things done because of your fatigue?	1.78	4.37		X
FATIMP16	How often did you have trouble finishing things because of your fatigue?	1.89	3.82		X
FATIMP49	To what degree did your fatigue interfere with your physical functioning?	4.05	3.67		X
FATEXP48	How often did you find yourself getting tired easily?	1.30	3.37		X
FATIMP30	How often were you too tired to think clearly?	2.16	3.26	X	X
FATIMP33	How often did your fatigue limit you at work (include work at home)?	3.95	3.17	X
FATEXP7	How often did you feel your fatigue was beyond your control?	1.00	2.76
FATIMP14	How often did your fatigue make it difficult to organize your thoughts when doing things at work (include work at home)?	1.41	2.63
FATEXP26	How often were you too tired to enjoy life?	1.70	2.43		X
FATIMP17	How often did your fatigue make it difficult to make decisions?	1.32	2.13
FATEXP34	How tired did you feel on average?	1.73	2.09
FATIMP9	How often did you fatigue make it difficult to plan activities ahead of time?	1.62	2.09
FATEXP21	How fatigued were you when your fatigue was at its worst?	1.84	2.07
FATIMP4	How often did your fatigue interfere with your social activities?	2.68	1.93		X
FATEXP5	How often did you experience extreme exhaustion?	1.19	1.93	X
FATIMP29	How often were you too tired to leave the house?	1.38	1.91
FATIMP21	How often were you too tired to take a bath or shower?	1.81	1.34	X
FATIMP15	How often did your fatigue interfere with your ability to engage in recreational activities?	1.05	1.15
FATIMP26	How often were you too tired to socialize with your family?	1.24	0.67
FATIMP6	How often did your fatigue make you feel slowed down in your thinking?	1.43
FATEXP22	How often were you bothered by your fatigue?	1.27
FATIMP19	How often were you too tired to do your household chores?	1.27
FATIMP56	How often were you too tired to socialize with your friends?	1.08
FATIMP24	How often did you have trouble starting things because of your fatigue?	0.86
FATIMP25	How often was it an effort to carry on a conversation because of your fatigue?	0.81
FATEXP20	How often did you feel tired?	0.78		X
FATEXP49	How often did you think about your fatigue?	0.76
FATEXP51	How easily did you find yourself getting tired on average?	0.76
FATIMP53	How often were you too tired to take a short walk?	0.76
FATIMP42	How often were you less effective at home due to your fatigue?	0.73
FATIMP55	How often did you have to force yourself to get up and do things because of your fatigue?	0.70
FATIMP13	How often were you too tired to do errands?	0.65
FATEXP50	How fatigued were you on the day you felt least fatigued?	0.59
FATEXP19	How often were you physically drained?	0.54
FATEXP54	How often did you have physical energy?	0.54
FATIMP20	How often did your fatigue make you feel less alert?	0.43
FATIMP10	How often did your fatigue make it difficult to start anything new?	0.38
FATEXP18	How often did you run out of energy?	0.32		X
FATIMP11	How often did your fatigue make you more forgetful?	0.30
FATEXP42	How much mental energy did you have on average?	0.27
FATEXP46	On how many days was your fatigue worse in the morning?	0.27
FATIMP40	How often did you have enough energy to exercise strenuously?	0.24		X
FATIMP8	How often were you too tired to watch television?	0.22

Relevance indices were calculated as the arithmetic mean rank across raters (RI-CL₄₄ for clinician raters, RI-MS₂₀ for raters with MS)