[sooheon]

Better in what dimension? It's not a repeatable intervention, it's not controlled, it's observational. It's not a study on the same null hypothesis.

[notahacker]

If your claim concerns common habits of populations with limited or no artificial light sources, observational studies of multiple populations with no artificial light sources is a superior way of assessing it than a prior study which imposed very specific periods of light deprivation on a study sample accustomed to nightly routines governed by available light to see how their behaviour changed.