I hope this topic can provide some clarity to an issue I see significant confusion over (and is even incorrect on the Fallout Wiki based on my own experiences): Have you personally had one of your Settlers die?
If so, what were the circumstances of that death? What job were they assigned to?
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In my personal experience (PS4, Normal difficulty in case either of those matter,) I have never had a normal Settler die.
Even during attacks, they'll just go to the ground like a wounded companion ("knocked out") after taking enough damage. Once the fight is over, they get back up and go back to work. I've witnessed this for farmers, guards, and traders.
Two exceptions though:
- Provisioners - I have seen a Provisioner killed. (By a deathclaw spawning under the bridge near the Drive-In. He was in pieces when I found him, while, in that same fight, a significantly less armed and armored trader was merely "knocked out" as described above.)
- Synth Settlers - The entire settlement turns on them and they usually die very quickly. Synth components found on their corpses to confirm.