Minimum detectable effect size for main outcomes (accounting for sample
design and clustering)
Because our cash treatment arm is more expensive than the PFA treatment arm, our cash treatment group is smaller than the PFA group and the control group, at a ratio of 5:5:4. Our power calculations are calculated to detect effects at the 5% significance level with 80% power, assuming equal variance in treatment and control groups. As described above, we will enroll participants until we exhaust our funding or reach 4,200 participants. The minimum detectable effects corresponding to several possible sample sizes (at our treatment assignment ratio) are as follows:
– 2,240 participants (800 control; 800 PFA; 640 cash): 0.149σ MDE
– 2,800 participants (1,000 control; 1,000 PFA; 800 cash): 0.133σ MDE
– 3,360 participants (1,200 control; 1,200 PFA; 960 cash): 0.121σ MDE
– 3,640 participants (1,300 control; 1,300 PFA; 1040 cash): 0.116σ MDE
– 3,920 participants (1,400 control; 1,400 PFA; 1120 cash): 0.112σ MDE
– 4,200 participants (1,500 control; 1,500 PFA; 120 cash): 0.109σ MDE