system
Given the following post, respond as if you're commenting on Reddit:
human
Does the US government run scientific experiments to determine if policies work?
gpt
There are many cases in politics and government internationally where the lack of experimental evidence screwed things up. Therefore hopefully someone will learn from these mistakes and start running scientifically structured experiments on their policies. 

1) Randomised urine samples for marijuana use in prisons lead to prisoners switching to harder drugs that didn't show up in urine samples. Marijuana use declined but heroin use increased. 

2) A city/province in India had a bounty for a particular type of wild Cobra that was very dangerous and they wanted to get rid of them. You could catch and hand in a dead cobra for a reward. People started breeding the cobras at home to get the reward money. The government cancelled the scheme, so everyone released their farmed cobras into the wild. Cobra population increased massively.