Computerised cognitive behavioural therapy for the treatment of depression in people with multiple sclerosis: external pilot trial

Table 6 Sample size estimates for a definitive trial stratified by outcome measure, power and effect size

Outcome measure	Power (%)	Effect size		Sample Size per group	Total sample size (attrition adjusted)
		Approximate mean difference	Standardised
BDI	90	5	0.6	35	70
		3	0.3	90	180
		2	0.2	195	390
	80	5	0.6	25	50
		3	0.3	65	130
		2	0.2	145	290
MSIS-29 subscale
Psychological	90	3	0.3	95	190
		2	0.2	220	410
	80	3	0.3	70	140
		2	0.2	155	310
Physical	90	6	0.3	115	230
		4	0.2	260	520
	80	6	0.3	85	170
		4	0.2	195	390

ISSN: 1745-6215