TABLE 4.

Factor Loadings and Fit for Unidimensional Confirmatory Factor Analysis Models for Six and Seven Items from the PROMIS F-SF

	Seven item model				Six item model
Item	FMS (N = 72)	SCD (N = 60)	CMR (N = 62)	Pregnancy (N = 72)	FMS (N = 72)	SCD (N = 60)	CMR (N = 62)	Pregnancy (N = 72)
1	.34	.63	.57	.44	.35	.63	.56	.44
2	.69	.82	.66	.77	.69	.83	.67	.77
3	.82	.90	.85	.93	.80	.90	.85	.93
4	.64	.88	.86	.73	.64	.88	.86	.73
5	.65	.85	.80	.66	.66	.85	.80	.66
6	.49	.66	.47	.50	.49	.66	.47	.50
7	.20	.13	.52	.02	--	--	--	--
Fit
χ²	27.35*	14.84	13.59	29.42^**	12.74	10.97	9.47	23.32^**
df	14	14	14	14	9	9	9	9
CFI	0.91	0.99	1.0	.87	0.97	0.99	1.0	.88
TLI	0.87	0.99	1.0	.81	0.96	0.98	1.0	.80
RMSEA^a	0.12	0.03	0.0	.12	0.08	0.06	.03	.15
95%CI	[.03, .19]	[0, .14]	[0, .13]	[.04, .20]	[0, .18]	[0, .18]	[0, .16]	[.06, .24]

Note. Complete factor solutions (unstandardized factor loadings, uniquenesses, and standard errors) are available in Supplemental Digital Content 2. CFI = comparative fit index; CI = confidence interval; CMR = cardiometabolic risk; df = degrees of freedom; FMS = fibromyalgia syndrome; RMSEA = root mean squared error of approximation; SCD = sickle cell disease; SE = standard error; TLI = Tucker-Lewis Index.

When df > χ² , RMSEA is set to 0 (Browne & Cudeck, 1993). In simulations with small sample sizes, small degrees of freedom, and a correctly specified model, RMSEA indicates a poor fitting model more often than theoretically expected (Kenny, Kaniskan, & McCoach, 2015).

p < .05,

^**

p < .01.