[wjnc]

They included fixed effects for hospitals and surgeons: "To test whether our findings were affected by including both hospital and surgeon fixed effects in the same regression models." [1]

Perhaps the link could be changed to the paper itself?

[1] https://www.bmj.com/content/371/bmj.m4381

[throwawaylolx]

>Perhaps the link could be changed to the paper itself?

Especially since OP's link won't load.