. Author manuscript; available in PMC: 2010 Feb 28.

Published in final edited form as: Arch Dermatol. 2008 Feb;144(2):173–180. doi: 10.1001/archderm.144.2.173

Table 3.

Responsiveness, Power, and Sample Size Requirements^a

Responsiveness Index (or Effect Size)	SD	Sample Size, No.	Power
CLASI Activity Change of 11.0
0.20	55.0	60	0.80
0.40	27.5	40	0.84
		50	0.87
		55	0.90
0.50	22.0	25	0.78
		30	0.85
		35	0.89
		40	0.93
0.61	18.0	15	0.73
		20	0.84
		25	0.91
0.80	13.8	10	0.75
		15	0.90
1.00	11.0	10	0.90

CLASI Activity Change of 9.0
0.20	45.0	60	0.45
0.40	22.5	40	0.80
		45	0.84
		50	0.87
		55	0.90
0.50	18.0	25	0.78
		30	0.85
		35	0.89
		40	0.93
0.60	15.0	20	0.83
		25	0.90
		30	0.94
0.80	11.3	10	0.75
		15	0.90
1.00	9.0	10	0.90

Abbreviation: CLASI, Cutaneous Lupus Erythematosus Disease Area and Severity Index.

One sample, paired t test; α=.05; 1-tailed; SD unknown. Power calculations were performed using PASS statistical software (Number Cruncher Statistical Systems, Kaysville, Utah).