The _average_ quality of those who where laid off is indeed probably a bit lower than the average quality of those who weren't.
But there's so much variance within those groups! The very _worst_ way of using that information that is:
- Interview everyone; run them through the full assessment process
- Once you have a successful group through the process, nix anyone with this trait
Instead, you arguably want to more thoroughly reference check folks who were laid off, in the same way you want to more thoroughly assess someone's technical ability who doesn't have a technical background. That lets you incorporate _more_ information, rather than acting on the very low-information signal of them being laid off.
But there's so much variance within those groups! The very _worst_ way of using that information that is:
Instead, you arguably want to more thoroughly reference check folks who were laid off, in the same way you want to more thoroughly assess someone's technical ability who doesn't have a technical background. That lets you incorporate _more_ information, rather than acting on the very low-information signal of them being laid off.