Psychometric evaluation of the PROMIS SD-SF-8b instrument in individuals experiencing vasomotor symptoms due to menopause

Table 2 Internal consistency reliability analysis

Item	Baseline		Week 12
Item	Alpha item deleted	Cronbach’s alpha (95% CI)	Alpha item deleted	Cronbach’s alpha (95% CI)
PROMIS SD-SF-8b total score		0.915 (0.906, 0.922)		0.935 (0.928, 0.941)
Item 1: my sleep was restless	0.903		0.930
Item 2: I was satisfied with my sleep	0.899		0.924
Item 3: my sleep was refreshing	0.904		0.924
Item 4: had difficulty falling asleep	0.922		0.941
Item 5: had trouble staying asleep	0.902		0.925
Item 6: had trouble sleeping	0.898		0.920
Item 7: got enough sleep	0.903		0.926
Item 8: my sleep quality was…	0.895		0.920

Cronbach’s alpha is calculated between each item and the total score omitting the item
CI Confidence interval; PROMIS SD-SF-8b Patient-Reported Outcomes Measurement Information System Sleep Disturbance – Short Form 8b

ISSN: 1477-7525