Knowing the sample size in the original study was 366 (184 placebo), the researchers would be able to detect a proportion difference of .12 (i.e., .30 for placebo vs .42 for treatment, as per the original study results), which corresponds to a Cohen h of .26, with 80% power using an alpha value of .05, and thus this analysis would be adequately powered (power analysis conducted with G*Power, http://www.gpower.hhu.de/en.html). In essence, the researchers simply want to attempt to replicate the original study findings using modified MADRS response rates.