In November 2012 the states of Colorado and Washington approved ballot initiatives that legalized marijuana for recreational use under state law. Two years later, Alaska and Oregon followed suit. In November 2016 as many as 11 other states will likely consider similar measures, through either ballot initiative or state legislative action.
Supporters and critics make numerous claims about the effects of state-level marijuana legalization. Advocates think that legalization reduces crime, raises revenue, lowers criminal justice expenditure, improves public health, improves traffic safety, and stimulates the economy. Critics argue that legalization spurs marijuana and other drug or alcohol use, increases crime, diminishes traffic safety, harms public health, and lowers teen educational achievement. Systematic evaluation of those claims after legalization, however, has been limited, particularly for Oregon and Alaska.
This paper assesses the effect to date of marijuana legalization and related policies in Colorado, Washington, Oregon, and Alaska.
Each of those four legalizations occurred recently, and each rolled out gradually over several years. The data available for before and after comparisons are therefore limited, so our assessments of legalization’s effect are tentative. Yet some post-legalization data are available, and considerable data exist regarding earlier marijuana policy changes—such as legalization for medical purposes—that plausibly have similar effects. Thus available information provides a useful if incomplete perspective on what other states should expect from legalization or related policies. Going forward, additional data may allow stronger conclusions.
Our analysis compares the pre- and post-policy-change paths of marijuana use, other drug or alcohol use, marijuana prices, crime, traffic accidents, teen educational outcomes, public health, tax revenues, criminal justice expenditures, and economic outcomes. These comparisons indicate whether the outcomes display obvious changes in trend around the time of changes in marijuana policy.
Our conclusion is that state-level marijuana legalizations to date have been associated with, at most, modest changes in marijuana use and related outcomes. Our estimates cannot rule out small changes, and related literature finds some effects from earlier marijuana policy changes such as medicalization. But the strong claims about legalization made by both opponents and supporters are not apparent in the data. The absence of significant adverse consequences is especially striking given the sometimes dire predictions made by legalization opponents.
The remainder of the paper proceeds as follows. The next section outlines the recent changes in marijuana policy in the four states of interest and discusses the timing of those changes. Subsequent sections examine the behavior of marijuana use and related outcomes before and after those policy changes. A final section summarizes and discusses implications for upcoming legalization debates.
Read more here: http://www.cato.org/publications/policy-analysis/dose-reality-effect-state-marijuana-legalizations