The same observed estimates for cluster size, reliability and the average correlation over the five waves of data was used for these analyses. Additionally, the estimates of the pooled variance were as follows: σ=10.7 (pooled: 11.1 at screen, 9.8 at baseline, 11.2 at 3 months, 10.2 at 6 months, 11.4 at 9 months, 10.6 at 12 months). The following effect sizes were examined: δ=3.5 to 3.8 (DBP point reduction per year in intervention group), d= δ/σ (where δ is average point reduction over one year and d is Cohen’s d). As shown, with about 120 per group, effect sizes as low as 2.21 can be detected. (See figure 4 and table 4).