Table 4.

Effect of study length on the power of the study

Scenario	Estimated power	Threshold of statistical significance	HCEQ Standard Deviation	Minimum detectable difference (Cohen’s effect size of 0.6)	Intra-cluster correlation	Adjusted standard deviation	Number of clusters (clinics)	Totalsample size	Study length (months)	Mean number of patients per clinic
1	0.519	0,05	2.46	1.476	0,02	2.65	6	54	1	9
2	0.76	0,05	2.46	1.476	0,02	2.85	6	108	2	18
3	0.88	0,05	2.46	1.476	0,02	2.98	6	162	3	27
4	0.92	0,05	2.46	1.476	0,02	3.21	6	216	4	36
5	0.948	0,05	2.46	1.476	0,02	3.37	6	270	5	45
6	0.963	0,05	2.46	1.476	0,02	3.53	6	324	6	54