Notable new Cato working paper examines "Marijuana Policy in Colorado"

Dr. Jeffrey Miron, who is director of economic studies at the Cato Institute and director of undergraduate studies in the Department of Economics at Harvard University, has just produced this significant new Cato working paper titled "Marijuana Policy in Colorado."  The paper is relatively short, though it includes lots of data, and here is its Executive Summary and its closing paragraphs:

In November 2012, voters in the states of Colorado and Washington approved ballot initiatives that legalized marijuana for recreational purposes.  Alaska, Oregon, and the District of Columbia are scheduled to consider similar measures in the fall of 2014, and other states may follow suit in the fall of 2016.

Supporters and opponents of such initiatives make numerous claims about state-level marijuana legalization.  Advocates believe legalization reduces crime, raises revenue, lowers criminal justice expenditure, improves public health, improves traffic safety, and stimulates the economy.  Critics believe legalization spurs marijuana use, increases crime, diminishes traffic safety, harms public health, and lowers teen educational achievement.  Systematic evaluation of these claims, however, has been absent.

This paper provides a preliminary assessment of marijuana legalization and related policies in Colorado.  It is the first part of a longer-term project that will monitor state marijuana legalizations in Colorado, Washington, and other states.

The conclusion from this initial evaluation is that changes in Colorado’s marijuana policy have had minimal impact on marijuana use and the outcomes sometimes associated with use.  Colorado has collected non-trivial tax revenue from legal marijuana, but so far less than anticipated by legalization advocates....

The evidence provided here suggests that marijuana policy changes in Colorado have had minimal impact on marijuana use and the outcomes sometimes associated with use.  This does not prove that other legalizing states will experience similar results, nor that the absence of major effects will continue.  Such conclusions must await additional evidence from Colorado, Washington, and future legalizing states, as well as more statistically robust analyses that use non-legalizing states as controls.

But the evidence here indicates that strong claims about Colorado’s legalization, whether by advocates or opponents, are so far devoid of empirical support.

Cross-posted at Marijuana Law, Policy & Reform