Table 2.

Descriptive data for the Pittsburgh Fatigability Scale (PFS).

	Cronbach’s alpha (>0.70)	SEM percent (<10%)	Floor percent (<20%)	Ceiling percent (<20%)	Mean (SD)
Fibromyalgia
PFS Physical	0.86	9.5	0.0	0.0	32.2 (8.2)
PFS Mental	0.85	16.5	1.6	0.0	24.4 (10.4)
Multiple sclerosis
PFS Physical	0.85	10.7	0.0	1.6	30.4 (8.4)
PFS Mental	0.91	15.9	0.0	1.6	23.0 (12.2)
Healthy adults
PFS Physical	0.88	20.9	2.4	0.0	15.2 (9.3)
PFS Mental	0.88	30.5	4.9	0.0	10.2 (9.0)
Combined sample
PFS Physical	0.91	13.9	0.9	0.5	24.8 (11.8)
PFS Mental	0.91	20.4	2.4	0.5	18.4 (12.4)

SD: standard deviation; SEM: standard error of measurement.

Parentheses indicate reliability criterion.