When there is uncertainty in the HC response rate but this uncertainty is not considered, Makuch and Simon's method produces a sample size that gives a considerably lower power than that specified.
This produces a sample size of 333 per group.
These assumptions, together with an analysis of covariance adjusted for baseline scores and for clustering, produce a sample size of 67 patients per intervention arm to achieve 80% power to detect the above differences.
Sample size estimation using economic end points is possible, but it is both time consuming, thus generally infeasible prior to obtaining funding, and will more likely produce a sample size that is larger than that required for the clinical effect; this increases the cost of a trial, and thus deceases the likelihood of successfully receiving funding.
The first 100,000 iterations in each run were discarded, and the phylogeny and additional model parameters were sampled every 100 generations in the last 200,000 iterations; thus, each run produced a sample of size 2,000 from the posterior.
An average of 15 patients per centre are expected to be enrolled, producing a total sample size of 6 000 patients.
We plan to recruit approximately 50 participants from each of the three hospital sites and from the community, producing a total sample size of 200.
A target of 60 participants within each village was set, to produce a final sample size of 720.
Calculation according to these values produced a minimal sample size of 118 cases.
Because the students were to be sampled in clusters by schools, a design effect of 1.3, estimated from Williamson et al. [ 50], was applied to produce a required sample size of 455.
