The changing attitudes toward marijuana can be difficult to fit into our understanding of crime. at the federal level, the drug is classified as a controlled substance and possession and distribution may carry severe penalties. in most states, possession is a criminal offense with penalties including jail. in a few states, possession is treated as a misdemeanor and in a handful of states, beginning with colorado and washington, recreational marijuana possession is now legal. what does this suggest about the difficulties of measuring changes in crime rates over time?