Shortening of the Pittsburgh Sleep Quality Index Survey Using Factor Analysis

Table 2

Agreements tests between “good” and “poor” sleeper scored by original and “shortPSQI.”

Original survey	“shortPSQI”		Total
	Poor sleepers	Good sleepers
Poor sleepers	423	84	507
Good sleepers	19	720	739
Total	442	804	1246

Kappa value 0.83 indicates an agreement between original and “shortPSQI,” based on a cut-off of 5 and 4 in PISQ and “shortPSQI,” respectively; McNemar’s test indicated a lack of agreement or, rather, a lack of symmetry of false negative and false positive proportions. Based on the analyses, all global values greater than 4 in “shortPSQI” total score are detecting poor sleepers.