The effect of marijuana policy on crime is examined in this paper using a difference-in-difference method. The crime rates in states that legalized medical marijuana were compared to the rates in states that prohibit medical marijuana. This effect was investigated during two time periods: 1995-2010 and 2000-2010. The results suggest that legalizing medical marijuana from 2000-2010 resulted in an increase in both violent and nonviolent crime. During the period of 1995-2010, however, the results do not suggest any increase in these crimes.

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