I was instantly reminding of the WWII aircraft engineers who inspected the damage to planes that returned from bombing raids, thinking to provide better protection to the most damaged areas of the plane. But someone pointed out that planes damaged in those areas made it back — those were the planes being inspected — and that the key was to figure out what damage had prevented planes from returning.

The easy data to find was the damage to planes that returned, so that was the data they wanted to use. "Easily accessible" is not the same as "useful."