An alternative method for estimating samples sizes was also tested (Campbell, Julious, and Altman 1996). This uses published tables which estimate the sample size (per group) required to identify a pre-specified difference in two proportions at at a 5% significance level with 80% power. The group sizes are then adjusted to take into account any differences in group size. For example, if the group with depression represents 8% of the total population, then to detect a difference in uptake of 65% amongst people without depression and 60% amongst people with depression, an overall sample size of 425 is required, of which 34 would need to have depression and 391 would not have depression. The overall sample size required for a range of differences in uptake rates are presented in Table 3 (the uptake rates are all multiples of 5% as these values are used in the published tables).