[maxbond]

> [T]he author doesn't explain "why", just "how".

The below seems like a "why" to me.

> The criteria for selecting the data are an atttempt to get the primary efficacy outcome, and to ensure that each trial occurs only once in our dataset. The selection for |z|<20 is because such large z-values are extremely unlikely for trials that aim to test if the effect is zero.

[polygamous_bat]

Ah I am sorry, seems like a comment was posted later (Jan 9th) providing a justification of their criteria. However, the reply comment it was posted on wasn't there when I first read the article and the comments on Jan 8th.