Function to calculate sample size requirements for a stepped wedge cluster randomised study.

Function to calculate sample size requirements for a stepped wedge cluster randomised study.

get_ss_swedge(z1 = 1.96, z2 = 0.84, p1, p2, deff)

Arguments

z1	The z-score indicating level of significance (confidence interval). Default at 1.96 for 95% confidence interval.
z2	desired power. Default at 0.84 for 80% power.
p1	Expected proportion for control group.
p2	Expected proportion for intervention group
deff	Design effect of a stepped wedge cluster randomised study

Value

A numeric value of sample size needed for a stepped wedge cluster ranomised study

Examples

 get_ss_swedge(z1 = 1.96, z2 = 0.84,
               p1 = 0.2, p2 = 0.15,
               deff = get_deff_swedge(k = 2, b = 1, t = 1,
                                      icc = 0.034, size = 192))
#> [1] 2552.836