Psychometric Evaluation of the Perceived Stress Scale in Multiple Sclerosis

Table 4

Floor effects and ceiling effects, reliability coefficients, and item-total correlations. Floor effects refer to the percentage of participants who reported the lowest possible score. Ceiling effects refer to the percentage of participants who reported the highest possible score. For floor and ceiling effects, more than 15% of the sample reporting the lowest or highest score is indicative of a floor or ceiling effect. Cronbach’s alphas are ideally above .70 and item-total correlations should be above .40.

Scale	Floor effect % (𝑁)	Ceiling effect % (𝑁)	Cronbach’s alpha	Item-total correlations range
PSS14-Total	0.4% (2)	0.0% (0)	.91	.126 to .758
PSS14-Stress	0.7% (3)	0.4% (2)	.84	.208 to .727
PSS14-Coping	4.9% (22)	0.0% (0)	.88	.488 to .770
PSS10-Total	1.1% (5)	0.0% (0)	.91	.588 to .771
PSS10-Stress	2.5% (11)	0.4% (2)	.87	.589 to .724
PSS10-Coping	7.2% (32)	0.0% (0)	.88	.688 to .785
PSS4-Total	7.2% (32)	0.2% (1)	.84	.643 to .706
PSS4-Stress	12.3% (55)	2.9% (13)	.73	.577
PSS4-Coping	12.6% (56)	0.9% (4)	.78	.639

PSS: Perceived Stress Scale.