Like all management, just because you can control and measure something (sentencing) doesn't mean it will help you achieve your goal (lower crime). Think of it

Like all management, just because you can control and measure something (sentencing) doesn't mean it will help you achieve your goal (lower crime). Think of it in terms of the broken window effect - if people (all subsections of soceity) know that they are very likely to be caught, then they are very unlikely to commit a crime no matter what the punishment. Only un-meditated crimes would likely slip through the gap. Also if a cop says it, it may mean nothing, but then when coders say different things, it would mean equally little would it not? At least the cop has real world experience. That said I'll see if I can find some studies to back it up.