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Submitted by Seb on

Hi Ben, the program has been very useful, thank you. I've been working on a partial population design since we are interested in spillover effects. We are giving equal weight to both the MDE_T and MDE_S and the program gives us that the proportions should be around 44% of the clusters for pure control and the rest for saturation at a 50% rate. I wanted to see the possible effects on these two MDEs if we had a lower take-up rate than expected. As expected, the MDE_T goes up as the effective saturation rate lowers.To my surprise, no matter how much I lowered the saturation for the treated clusters, the MDE_S will always decrease. This is of course leaving the proportions fixed to the initial minimizing value.
My intuition would tell me that the MDE_S in a partial population design would have an inverted U relation with the saturation rate: both extremes would imply a high variance. I went through the equations in the paper and they match what I see in the program.
Am I missing something? Before I go into calculating the MDEs myself I wanted to know if my intuition is wrong. Any insights would be very appreciated, thanks!