Table 2.

Descriptive statistics for samples used in the different steps of instrument evaluation

		Item analysis (109 subjects, 889 observations)			Test-retest reliability (55 subjects, 110 observations)
Pain location	Characteristic	Mean (SD*)	Item–total correlation	ICC+	Mean (SD*)
	Frequency	11.7 (9.2)	0.79	0.34	7.3 (8.5)
	Duration	11.4 (9.2)	0.79	0.39	6.9 (8.2)
Masseter pain	Intensity	7.9 (6.8)	0.85	0.32	5.3 (6.6)
	Unpleasantness	7.8 (7.1)	0.86	0.31	5.1 (7.1)
	Endurability	6.3 (6.5)	0.83	0.30	4.3 (6.7)
	Frequency	13.5 (9.0)	0.75	0.34	8.8 (9.2)
	Duration	12.7 (9.1)	0.74	0.38	8.5 (9.0)
TMJ pain	Intensity	9.2 (7.1)	0.84	0.29	6.8 (7.5)
	Unpleasantness	9.0 (7.4)	0.86	0.29	6.3 (7.5)
	Endurability	7.1 (6.8)	0.85	0.28	5.0 (7.0)
	Frequency	8.7 (8.0)	0.75	0.51	5.4 (7.0)
	Duration	9.1 (8.3)	0.72	0.49	5.6 (6.7)
Temple pain	Intensity	7.0 (6.8)	0.76	0.51	4.9 (6.4)
	Unpleasantness	7.0 (7.0)	0.76	0.52	4.9 (6.5)
	Endurability	5.8 (6.3)	0.76	0.51	3.0 (4.9)
Total SSI score		124.4 (94.2)			86.6 (83.2)

Possible range is from 0 to 27 for each scale

^*SD – standard deviation

⁺ICC - Intraclass correlation coefficient

Note: means and SD calculated across all 889 observations