Some of this is really just common sense. I believe the following:

- If murder were not prosecuted, or punished by only a day in jail, murder rates would increase. It would effectively be legal.

- Changing the sentence on murder from 10 years to life, however, would be unlikely to have any marginal deterrent effect.

Stated more generally, I think many sentences in this country are horrifically long, and dramatically shortening them would not increase crime. But if you decrease them to a level where they are de minimis compared to the benefit of the crime, or just not prosecuted at all, I don’t need a study to tell me crime will increase. It is human nature.

Exactly! Beyond a certain threshold, increasing punishment severity has diminishing returns (or negative, if you count the fiscal and societal costs of incarceration).

I've heard incorrect folk wisdom parroted as if it were true, before, so I'll wait for the study.

Plenty of people claim they have a grasp on common sense, and many of them disagree.

Do you eat when you’re hungry and put on a raincoat outside when it’s raining, or do you wait for a study?

Hilarious that you bought up "eating when hungry" as an example of common sense considering all the discussion about that recently. Folk wisdom loses, again :) I think I will wait for the study.