Thanks very much for your helpful responses!
So i guess in your example of spurious selection, regions X and Y are equally close to hospitals, exposed to natural catastrophes, etc? Or is your point that even if region X has a hospital and Y doesn't, it's not strictly 'geography' causing a difference in mortality, it's 'closeness to a hospital'.
I just find the Core Reading confusing (quoted on page 7) that geographical location is a proxy factor but climate/geography "provide a direct causal explanation of the observed differences" in mortality.
From a quick google it seems that the term 'spurious selection' is related to the 19th century concept of 'spurious correlation' which seems to simply mean that: 'Correlation Is Not Causation' Spurious Correlation - an overview | ScienceDirect Topics and nicely 'correlates' with your answer. Anyway, now back to past papers
Last edited: Mar 26, 2023