Does legalizing marijuana help or harm Americans? Weighing the statistical evidence | Opinion


By Liberty Vittert

The legalization of marijuana has been a topic of contention and confusion for both sides of the debate.

The federal government still deems it illegal. But marijuana has been legalized for recreational use in 10 states and the District of Columbia, and a further 21 broadly legalize medical marijuana.

Researchers like myself finally have some data to assess claims made on both sides. Let’s take a closer look at three major arguments around marijuana legalization – and how the statistics stack up against them.

How much money will states earn from marijuana taxes?

One of the biggest pro-legalization arguments was that states would be able to bring in a new source of tax revenue.

Colorado, for example, imposes a 15 percent excise tax from cultivator to retailer and a further 15% sales tax on the end customer.

In 2018, Colorado legal pot sales topped $1.2 billion, with the state pulling in about $270 million in taxes. Compare that to the approximately $45 million that the state collected in tax on alcohol that same year.

A study from Georgia State University found that alcohol sales fell by 15 percent in states where only medical marijuana had been legalized and by 20% in counties where recreational marijuana is sold legally. However, the states made more than enough back from marijuana sales, since marijuana taxes are typically greater than alcohol taxes.

Other states are reaping the benefits of marijuana taxes as well. California pulled in $345 million in 2018 and Washington $376 million. New Frontier Data, a cannabis data website, predicts the legalized cannabis market will grow to US$25 billion by 2025.

However, there are a lot of questions about how much tax revenue states will actually earn, especially considering that some states have missed their projections by a long shot.

For example, the governor of California predicted a much larger $643 million in revenue. Meanwhile, projections for Washington suggested that the state would earn only $160 million.

While projections for other types of goods are typically more reliable, this is an entirely new market and therefore prone to error. Why? Well, the jury is still out. Some researchers and pundits have guessed that in California taxes are too high, that the black market is too strong or that the red tape of bureaucracy is just too much.

Regardless, it’s clear that marijuana tax revenue has increased year over year for every state that has legalized recreational marijuana.

While naysayers are touting California’s missed projections, Colorado, while struggling to meet its projections in the first three years after legalization, eventually exceeded its projection.

Is legalized marijuana hurting youth?

A well-trodden argument against legalization is that it could lead youth to use it more. For example, anti-drug group DARE has blamed marijuana for a rise in school suspensions and youth suicide, among other things.

Here is the problem: Researchers simply don’t have enough data yet.

Studies have shown that youth marijuana use actually decreases in states where medical marijuana has been legalized. Researchers guess that this may be due to kids viewing marijuana as medicinal instead of recreational.

While other studies have suggested that legalizing marijuana can lead to increased use, this could simply be reporting bias. In other words, if it is legalized, people are more willing to be honest about use.

Three things to know about Pa.’s latest legal cannabis proposal

Other studies show quite the opposite. For example, Colorado teens had a statistically significant drop in marijuana use over the past three years since recreational legalization.

While there are strong indicators that the legalization of recreational marijuana leads to decreased use in youth, only time will give the final verdict.

Does marijuana increase crime?

Many who are against legal marijuana claim that it could lead to an increase in violent crime.

Even in Colorado last year, there were rumblings from former Gov. John Hickenlooper about banning marijuana, since crime in Colorado has been rising since 2014, the same year marijuana was legalized.

There is really no doubt that states which allow medical marijuana show absolutely no increase in their violent and nonviolent crime statistics. In fact, crime might actually decrease.

However, crime has increased in many of the cities where recreational marijuana is legal. Homicides in Seattle, D.C. and Denver – all major cities with legal marijuana – have increased over the past few years. But homicides have also increased in cities without recreational marijuana, such as Chicago, St. Louis, Baltimore, New Orleans and Kansas City.

A homicide increase over four years alone in cities where marijuana is legalized reveals absolutely nothing. This is a classic case for the statistical saying “correlation does not necessarily mean causation.” Take California, for instance. Murders in Oakland are down, but murders in Fresno are up. How can that be recreational marijuana’s fault?

However, legalized marijuana does seem to have an effect on the justice system. According to FBI crime data, in 2017, there were 659,000 marijuana arrests in the U.S. There were also 1.2 million violent crimes with victims, but only 518,617 arrests for these same violent crimes. This means that there are more than 700,000 victims who have suffered without justice.

Poll: 59 percent of Pennsylvania voters support legalizing recreational cannabis

In states with legalized recreational marijuana, police now no longer spend time on marijuana arrests and can spend more time on solving these types of crime. FBI data from Colorado and Washington show that crime clearance rates – the number of times that the police solved a crime – increased for both violent and property crimes after legalization.

While there are still many unknowns surrounding the legalization of recreational marijuana, I believe that this shows that it will be a positive influence.The Conversation

Liberty Vittert is a Visiting Assistant Professor in Statistics at Washington University in St Louis. She wrote this piece for The Conversation, where it first appeared.


  1. Marijuana consumers deserve and demand equal rights and protections under our laws that are currently afforded to the drinkers of far more dangerous and deadly, yet perfectly legal, widely accepted, endlessly advertised and even glorified as an All-American pastime, alcohol.

    Plain and simple!

    Legalize Nationwide!

    Fear of Marijuana Legalization Nationwide is unfounded. Not based on any science or fact whatsoever. So please prohibitionists, we beg you to give your scare tactics, “Conspiracy Theories” and “Doomsday Scenarios” over the inevitable Legalization of Marijuana Nationwide a rest. Nobody is buying them anymore these days. Okay?

    Furthermore, if all prohibitionists get when they look into that nice, big and shiny crystal ball of theirs, while wondering about the future of marijuana legalization, is horror, doom, and despair, well then I suggest they return that thing as quickly as possible and reclaim the money they shelled out for it, since it’s obviously defective.

    The prohibition of marijuana has not decreased the supply nor the demand for marijuana at all. Not one single iota, and it never will. Just a huge and complete waste of our tax dollars to continue criminalizing citizens for choosing a natural, non-toxic, relatively benign plant proven to be much safer than alcohol.

    If prohibitionists are going to take it upon themselves to worry about “saving us all” from ourselves, then they need to start with the drug that causes more death and destruction than every other drug in the world COMBINED, which is alcohol!

    Why do prohibitionists feel the continued need to vilify and demonize marijuana when they could more wisely focus their efforts on a real, proven killer, alcohol, which again causes more destruction, violence, and death than all other drugs, COMBINED?

    Prohibitionists really should get their priorities straight and/or practice a little live and let live. They’ll live longer, happier, and healthier, with a lot less stress if they refrain from being bent on trying to control others through Draconian Marijuana Laws.

  2. Many states have legalized cannabis, and none, voters nor legislators, want to reinstate prohibition.

    Colorado Governor John Hickenlooper was always against legal cannabis. He had no choice as the people forced legalization through a ballot inititive. He said other states should wait a couple of years before legalizing. After one and a half years of legalization even he has come around and admitted that it has gone smoother than expected:

    “It seems like the people that were smoking before are mainly the people that are smoking now,” Hickenlooper said as Colorado marked six months of legal recreational sales last week. “If that’s the case, what that means is that we’re not going to have more drugged driving, or driving while high. We’re not going to have some of those problems. But we are going to have a system where we’re actually regulating and taxing something, and keeping that money in the state of Colorado…and we’re not supporting a corrupt system of gangsters.”
    [SOURCE: “How Is Marijuana Legalization Going? The Price Of Pot Peace Looks Like A Bargain”. Forbes. Jul 2014]

    After two years he has reiterated this:

    “If you look back, it’s turned out not to be as vexing as some people like myself…. I opposed the original vote, didn’t think it was a good idea. But the voters spoke and we’re trying to make it work, and I think we are. Again, it’s not as vexing as we thought it was going to be.”
    [SOURCE: John Hickenlooper Says Legalizing Pot Not as Vexing as We Thought. WestWord. Apr 2015]

    And again after three years:

    “If I had that magic wand now, I don’t know if I would wave it,” he said. “It’s beginning to look like it might work.”
    [SOURCE: Governor who called legalization ‘reckless’ now says Colorado’s pot industry is working. LA Times. May 2016]

    Andrew Freedman, marijuana coordination director for the state, said the roll out has been successful:

    “Dispensaries have a 96 to 97 percent compliance rate with the state laws, and the massive spikes in public safety and health issues that some feared haven’t come to pass, he said. And while there’s more mention of cannabis-related issues in emergency room visits, they comprise less than 1 percent of the whole”
    [SOURCE: Legal cannabis roll out smooth, says marijuana czar for the state. Aspen Daily News. July 4, 2015]

    Denver Mayor Michael Hancock who was strongly opposed to cannabis legalization has also changed his mind and now supports the legal market:

    “Denver Mayor Michael Hancock, a Democrat who like Gov. Charlie Baker and Boston Mayor Marty Walsh ‘adamantly opposed’ legalization, told Boston Herald Radio’s ‘Morning Meeting’ on Monday that his fears did not come to fruition and that he is ‘converted.'”
    [SOURCE: “Denver’s Mayor Says He’s ‘Converted’ On Legal Recreational Marijuana”. WBUR News. June 2018]

    In Nov 2012 the people of Colorado voted 55% – 45% in favor of recreational cannabis legalization. Residents continue support for legalization:

    (for – against)
    52% – 38% [SOURCE: Majority in Colorado say legal marijuana good. CNN, April, 2014.]
    54% – 43% [SOURCE: Quinnipiac University, April 28, 2014.]
    54% – 43% [SOURCE: Quinnipiac University, July 21, 2014.]
    55% – 41% [SOURCE: Colorado Not Suffering Buyer’s Remorse Over Legal Marijuana, Poll Finds. Huffingtonpost, Sep, 2014.]
    58% – 38% [SOURCE: Quinnipiac University, Feb 24, 2015.]
    62% – 34% [SOURCE: Quinnipiac University, April 14, 2015.]

  3. Americans don’t have to like cannabis, but they should hate its prohibition. This prohibition law strikes at the very foundation of our society. It is a tool of tyrants, used to violate core American beliefs and nearly every aspect of the Bill of Rights.

    A populace that accepts and becomes accustom to overreaching government policies, such as the prohibition of relatively safe, popular substances, becomes more accepting of overreaching, powerful government in general. This devastates America, not a plant that has been used by mankind since the beginning of recorded history.

    Those who believe in limited government, personal responsibility, free markets, and individual liberty should embrace the ending of this irrational, un-American, fraudulently enacted cannabis prohibition experiment. It should be the cornerstone of current GOP policy.

    Federal studies show about half of the U.S. population has tried cannabis, at least 15% use it regularly, over 80% of high school seniors have reported cannabis “easy to get” for decades. This prohibition, like alcohol prohibition has had little of its intended effect. In many cases cannabis prohibition makes cannabis usage problematic where it would not have been otherwise, be it light, moderate, or heavy usage. For the most part, cannabis prohibition only successfully prohibits effective regulation.

    A few issues created by prohibition: there are no quality controls to reduce contaminants (harmful pesticides, molds, fungus, other drugs), there is no practical way to prevent regular underage sales, billions in tax revenue are lost which can be used for all substance abuse treatment, underground markets for all drugs are empowered as a far more popular substance is placed within them expanding their reach and increasing their profits, criminal records make pursuing many decent careers difficult, police and court resources are unnecessarily tied up by pursuing and prosecuting victimless ‘crimes’, public mistrust and disrespect for our legal system, police, and government is increased, which is devastating our country.

    Prohibition is also very expensive, though, a cash cow for a number of powerful groups such as those related to law enforcement and the prison industry. These organizations have powerful lobbies and influence that perpetuate a failed drug policy through ignorance, fear, disinformation and misinformation. This ensures an endless supply of lucrative contracts, grants and subsidies from the government and its taxpayers to support their salaries, tools of the trade, ‘correctional’ services, and other expenses. Cash, property and other assets from civil forfeiture laws also significantly fatten their coffers while often violating civil rights.

    America was built on the principles of freedom and liberty. In some cases there are extreme circumstances that warrant intervention with criminal law. In the case of mind-altering drugs we have already set this precedent with alcohol. Cannabis is less harmful than alcohol to the consumer and especially to others. If we are to have justice, then the penalties for using, possessing and selling cannabis should be no worse than those of alcohol.

    Regardless of legal status, a large market for cannabis will continue to exist as it has for decades. Either the underground controls the market and profits from it, or the state does…all while ending their assault on our citizens. Let’s end this costly, futile attempt to eradicate a plant that a majority of Americans believe should be legal.

  4. I did not know the fact that marijuana has been legalized for recreational use in 10 states and the District of Columbia, and a further 21 broadly legalize medical marijuana. I believe as the society grows is better to stay neutral in this controversy discussion since there are many facts that are still not been discussed yet. Thanks for sharing the map where you point out what states legalized marijuana as medical, recreational, or is just not legal yet.

  5. My sister and I have heard good things about recreational cannabis, but we wanted more info before we try it! I didn’t know marijuana taxes in the past few years have been higher than alcohol taxes and its revenue is helping the states that have it legalized. I’ll have to look more into that, so I’m not as scared to try cannabis and see its benefits, thanks to this post!


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