Bring Back 30-Day Sentences!

I'm sitting in my Law & Society class learning that, when people are considering the possibility of sanctions in considering whether to commit a crime, the certainty of a punishment matters a whole lot more than the severity. So, in other words, if Sanction A is a 50% chance of a 1-year jail sentence and Sanction B is a 25% chance of a 2-year jail sentence, both of which give an Expected Value punishment of six months, most people will be more scared of Sanction A than Sanction B. This is interesting for the death penalty debate, since trying to impose the death penalty makes it much harder to get the punishment imposed. But I think it's also interesting because over the past many decades we've moved away from giving people a 30-day sentence for run-of-the-mill offenses. This is probably a mistake, since it's probably easier to give people 30-day sentences than five-year ones. It's also vastly less destructive of social well-being. At the very least we wouldn't suffer much of a reduction in deterrence, and we'd move away from our 'throw everyone in jail forever' society.