Psychometric Evaluation of the Perceived Stress Scale in Multiple Sclerosis

Table 3

Factor analysis results: model fit indices.

	PSS-14			PSS-10			PSS-4
	One factor	Two factor	Bifactor	One factor	Two factor	Bifactor	One factor	Two factor
Perfect; Fit	𝜒^2=1124.54,; 𝑃<.001	𝜒^2=442.98,; 𝑃<.001	𝜒^2=181.28,; 𝑃<.001	𝜒^2=561.95,; 𝑃<.001	𝜒^2=156.23,; 𝑃<.001	𝜒^2=87.83,; 𝑃<.001	𝜒^2=11.18,; 𝑃=.004	𝜒^2=.53,; 𝑃=.470
Close fit	𝑃<.001	𝑃=.014	𝑃=.99	𝑃<.001	𝑃=.350	𝑃=.760	𝑃=.430	𝑃=.780
RMSEA	.110	.064	.031	.120	.053	.041	.046	<.01
CFI	.95	.99	1.00	.97	.99	1.00	1.00	1.00
RMSR	.078	.057	.030	.063	.036	.022	.018	.004
ECVI	1.31	.61	.39	.66	.27	.23	.045	.043
AIC	584.57	270.92	173.58	293.73	118.54	103.41	19.89	18.23

RMSEA: root mean square error of approximation, CFI: comparative fit index, RMSR: root mean squared residual, ECVI: expected cross validation index, AIC: akaike information criterion.