By its fundamental design, an observational study cannot account for everything. That is the critique and it is a valid one.
Most observational studies do in fact account for the first thing a random HN poster can come up with 5 seconds after reading the title. So there is very little value in such a comment.
Most observational studies do in fact account for the first thing a random HN poster can come up with 5 seconds after reading the title. So there is very little value in such a comment.