The existence of things like DNA tests causes people to want more evidence today before they’re willing to convict resulting in fewer dubious arrests. Which may mean we’re simply catching the wrong person less often, but we could also be letting more guilty people go. https://www.npr.org/2023/04/29/1172775448/people-murder-unso...
Yes, this is how the US legal system is designed.
>want more evidence today before they’re willing to convict
This is why you should be completely suspect of the data from the past. Law enforcement is great at going out, grabbing the usual suspects, then pinning some evidence on them. This is great for LEO. They get a win, the public feels safe, and they get reelected. It's unfortunate the actual killer is still on the street because it's a lot easier to frame someone than it is to do real (expensive) police work.
https://innocenceproject.org/all-cases/
https://en.wikipedia.org/wiki/Michael_Morton_(criminal_justi...
Which doesn’t mean we should do the old convict a random drifter in the area, just acknowledge there’s real negative consequences in both directions.