Body armor in the second Gulf war contributed greatly to an increased rate of amputations on soldiers.

Ah, survivor bias. Reminds me of analysis of damage to bombers in WW2. Data showed most damage was done to the wings and body of planes. The tail, cockpit and engines were rarely damaged. They responded by reinforcing those areas that were frequently damaged.

However they were only observing bombers that made it back to base and so data on planes that were shot down was missing. Luckily someone did eventually realise this and so the research could be used as evidence that strikes to the areas rarely recorded indicated a downed plane.