Marijuana is bad for the grades of people studying in the Netherlands

According to a study recently published in The Review of Economic Studies, access to legal marijuana may significantly reduce academic performance.

The study took advantage of a natural experiment in the Dutch city of Maastricht. In 2011, the city sought to pull back some of the marijuana tourism going to its coffee shops, where marijuana sales are legally tolerated. So through the local association of cannabis shop owners, it banned some foreigners of certain nationalities from buying pot at these venues.

This let researchers Olivier Marie and Ulf Zölitz, in the cleverly titled “‘High’ Achievers? Cannabis Access and Academic Performance,” compare the academic outcomes of Maastricht University students with varying levels of access to legal pot.

What they found: The students who weren’t allowed to legally access marijuana saw their grades significantly improve, especially in classes that require numerical and mathematical skills.

Here is the full Vox story.  I strongly believe it is morally wrong to throw people in jail for smoking such substances, but still policy decisions have real consequences, we should know what those are, and I am not convinced that full availability of marijuana is the optimal approach.

Here are ungated copies, noting there have been significant revisions in the paper along the way.


Here in my Canadian college town, we are hoping legal pot will help chill out the drinking related problems including violence, DUI and vandalism.

As for grades? Well, the smart ones have never been part of the party scene. My experience is that the top tier of students, the ones who move into the research positions and so on, are not at the bar and keeping things moderate.

I couls have sworn that I read a study somewhere demonstrating a positive correlation between academic performance and marijuana use. If anyone knows what Im talking about and can pull that study up, I'd be grateful.

An article about that

However, the author does not really give a way of finding the original studies.

Here in my Canadian college town, we are hoping legal pot will help chill out the drinking related problems including violence, DUI and vandalism.

Ha ha ha.

The assumption is that pot will be a replacement/substitution for alcohol, and not an add-on?

Weed is actually cheaper than beer despite being illegal in the US.

Not sure where this intel is coming from, but you can't even get a gram of cannabis for the same price as a 6-pack of your standard IPA. Furthermore, even in states where it is legal it's significantly more expensive to purchase from dispensaries than it is to purchase a product of similar quality from an illegal source.

"Furthermore, even in states where it is legal it’s significantly more expensive to purchase from dispensaries than it is to purchase a product of similar quality from an illegal source."

Without supply constraints, it's logical for the illegal source to be cheaper, Stolen cars and TV's sell at a significant discount also.

"Without supply constraints, it’s logical for the illegal source to be cheaper, Stolen cars and TV’s sell at a significant discount also."

This I understand, my point though is that restricting students' legal access to weed realistically is not synonymous with restricting their access to weed in general. This coming from a frequent user in an illegal state attending one of the nation's most prestigious universities.

"This I understand, my point though is that restricting students’ legal access to weed realistically is not synonymous with restricting their access to weed in general."

Sure, but I don't think anyone was claiming it did.

Ok, my intel might be very old.
But it's worth noting that one gram of weed will get several people high for hours.
I'm not sure that a six pack would be quite as effective.

" But it’s worth noting that one gram of weed "


Wouldn't the usual quantity be an Ounce? It's hard to believe a gram would last that long?

What does "cheaper than beer" mean? By weight?

by dose. assume it takes an average young male 6 beers to get suitably party-drunk (more than just a little happy hour relaxation), that costs about $10 (with variation by region and brand). assume it takes an average young male (without decades of accumulated tolerance) about 4 solid hits on a blunt to get suitably party-stoned. there's variation of course, but a typical blunt might be 1 gram (large one, intended to be shared in a group) and yield 20-30 solid hits. gram of weed costs no more than $20, and frequently less than that. the price per dose for this is probably in the neighborhood of $5-6.

Which leads to the old 1960s joke: How do you recognize Texans at a be-in? They're the ones with the dope AND the six-pack.

Let me second that about the drinking and performance. When I was in college in the early 70s there was a huge drinking problem (it was legal in DC when you were 18). Serious students drank on Friday and Saturday nights at most. Other students drank during the week. These were not the students you'd find in the library. Now that is purely anecdotal evidence, though I had a wide range of observations. Another related point - I saw kids who seemed well on their way to becoming alcoholics. I have met only one person in my life who continued heavy pot use past college. (And he did well enough to pass the bar exam.)

How did the authors of the study know that illegality meaningfully deterred access to pot? It was highly illegal then, and access was never a problem. In this study case, it would seem easy for those without access to purchase it from those with access. And in fact it would be an easy way for students with legal access to make money.

In the US the drinking age is 21, which means it is legal to purchase only if you are, in all likelihood, a college senior. Is there any access problem by undergraduates to alcohol on US college campuses? I would guess not, given the prevalence of black markets even in cases where access is illegal for everyone. If it is legal for some, you've basically just given a license to sell to one group, at the expense of the other.

There are lots of time wasting diversions when you are in college. In my days, it was drugs, alcohol, and members of the opposite sex. Lots of people played cards. Nowadays you have the added distraction of video games -- I can attest as the father of teens that they can waste many hours of the day doing this unless they have some kind of turn off switch. That personal turn off switch (sometimes activated by the first batch of poor grades) should be all that is needed. Finally, the comments of Art Deco are on point. One has to examine the alternatives.

You should look at the Vox article. The study addresses selection bias, because there were exogenous differences in enforcement based on nationality.

Does this tell us more about marijuana, or about grades?

B's are negotiaters. A's are resilience, perservence, etcetera. A- are decent. C's are where you make your money. If you only show up 3 times and pass a class, that's got to be an A. F's are tough. Not a good sign, but nonetheless perhaps a statement about the teacher, the class, the university. A modest protest. But do not protest douthat. You're suspect.

On one hand, between two fingers, a cigarette dallied; in the other, a half-eaten dawdling green apple.

My right hand holds a vial of tranquilizers
My left hand holds a loaded.38
I've got a young girl who's anticipating romance
But it's lookin' like she will have to wait

The law changed for sure but there's no data on the students. What do the grades show? A) the same set of students before and after law change, or B) a set of exchange students that left for greener pastures after the change?

Did you read the article? (I know you won't read the study.)

No one's perfect. So, where's the answer? Sections 1-6, page? why the cynicism?

'but still policy decisions have real consequences, we should know what those are'

Well, one would assume that leading lights at the GMU econ dept. would likely get behind raising the American drinking age then, at least if they are interested in increasing student performance. As noted by one of the authors of that study - '“The effects we find are large, consistent and statistically very significant,” Marie told the Observer. “For example, we estimate that students who were no longer able to buy cannabis legally were 5% more likely to pass courses. The grade improvement this represents is about the same as having a qualified teacher and, more relevantly, similar to decreases in grades observed from reaching legal drinking age in the US.”'

Your writing would be far better if you would drop the passive aggressive aggrieved tone.

But that would render a big part of his life meaningless.

Our culture has various norms about drinking being largely a nighttime practice, with daylight drinking being more for special occasions such as Memorial Day parties and tailgate parties and the like. Morning drinking is particularly frowned upon.

I don't know much about marijuana norms, but my vague impression is that there is less hostility toward getting high in the morning than there is with alcohol. Among students who drink, it seems like only a small percentage come to class drunk in the morning compared to the percentage of students who smoke marijuana who come to class high in the morning.

"it seems like only a small percentage come to class drunk in the morning": they must be really drunk if they're too drunk to see the benefits of just skipping the class.

But what about hangovers? I am told they are very common among America' s youth.

It's Europe. People is cool with 16 year olds drinking beer and wine.

"...daylight drinking being more for special occasions such as Memorial Day parties and tailgate parties and the like. Morning drinking is particularly frowned upon."

There's been an apparent significant change in American business culture from an acceptance of alcohol at a business lunch to a strict no alcohol during business hours policy that seems to prevail today. Has there been a noticeable effect? I'm not quite old enough to have ever experienced the former.

I was in the corporate world in Chicago from 1982-2000. I don't recall any three martini lunches, although I vaguely recall one drink as being somewhat acceptable at lunch. Mostly I recall the 1980s as being rather prim and proper during working hours, although not so much after hours. For example, my employer hosted beer bashes on Friday evening in the 1980s. I vaguely recall them fading out in the 1990s.

When I briefly moved from the competitor in the city to the competitor in the suburbs in the early 1990s, I recall being told that keeping a beer in my personal refrigerator for drinking while I was working late into the evening was not appropriate. But it was positioned to me as an old-fashioned tradition at my new firm. On the other hand, when I went back to the city firm in 1994, I kept the suburban firm's tradition of teetotaling in the office.

The three martini lunch was more of a 1950-60s thing. By 1982, Reagan was in office, and MADD was founded in 1980. The 21 year old drinking age was passed in 1984, only two years later. The 80s were if anything relatively anti-alcohol.

Carter made something of a name for himself by attacking the deductibility of the "three martini" lunch on corporate taxes.

States regulate the drinking age, and they raised it at different times in that era. The federal contribution was to make distribution of highway funds contingent on local drinking ages. New York, Massachusetts, and Maryland (among others) raised the drinking age before that went into effect.

My experience with a not insignificant number of pot smokers is this:

Most of them will smoke about the same way people drink, as you describe, at night, on weekends, not too frequently.
A minority of smokers will smoke more like alcoholics drink, every night, but probably not at work or during other important events
An even smaller minority will smoke constantly, smoking when the get up and many times during the day. Pot is more like prozac to them (with varying degrees of success at self medication)

That's pretty much my experience too.
There's a fair number of pot smokers who "wake and bake". It is not to be assumed that this is normal or universal pot smoking behavior.

+1. Marijuana in aggregate is no worse, and no better, than alcohol. For some individuals one is better than the other.

I think that's true. On the other hand, the side effects of alcohol are relatively severe also.

I support giving people choices. But I'm also don't believe in ignoring the consequences. Let the students make their own judgements, but cut the monetary aid sharply if their grades start to drop or if they switch to a Major with a poor ROI.

In my experience, alcohol is much worse, in effect and in after-effect. A hangover is your body's way of telling you to stop poisoning yourself.

Yeah, also, weed doesn't affect third parties as badly.
Not many kids complain about their dad getting stoned and then beating them up.

Not many kids complain about their dad getting stoned and then beating them up.

Michael Kinsley noted a generation ago that HHS had conducted an 'eager-beaver government study' which had revealed that about 1% of the youth of the nation were living in circumstances which met the definition of 'abuse' or 'neglect'. New York has about 3 million minors. About 25,000 are enmeshed in the foster care system. Strange as it may seem to you, it's not that common for fathers to 'beat up' their kids. Much more common is the father who has been told to cough up the cash and act as a baby sitter on demand, but otherwise get lost.

"Not many kids complain about their dad getting stoned and then beating them up."

The Foster children we got from the family that had been smoking weed hadn't been beaten. But all 4 girls had been suffering from neglect. Including severe lice, lack of bathing, dirty and improper clothes, and living off of snack food. We never did manage to get all of the kids to actually eat vegetables. At least one of the parents (or adults at the location, it was fuzzy) had been reading to them.

Smoking weed does have consequences.

Probably norms about MJ use need to evolve a bit with legalization, especially when it comes to teenagers in high school. I wouldn't be adverse to an 18 year old smoking age, at least until people get used to the idea that it's not ok to smoke weed in between classes.

Then there's the guy who aced the physics exam in my university, then played Pac-Man in the student union and got the highest score ever. Speed. These days it would be the Rx drug "Adderall" (a form of speed).

Go to school somewhere else.

Though it's wrong to put young men in jail for fapping away their lives in Mommy's basement, it's just as wrong to prevent men from telling young men that they're f***ups for doing it.

Because they are being put in jail for telling them it?

"it banned some foreigners of certain nationalities from buying pot at these venues."

Because how on earth would those 'certain nationalities' ever obtain pot if they're 'banned' BANNED I TELL YOU!

How did this get accepted by any journal? Do they expect people to believe that being 'banned' seriously affected the amount of pot available to them or do they expect people to believe that legal and illegal pot have different effects on users?

Reality doesn't fit your theory, so clearly reality is wrong.

You are correct that even after the ban, the quantity used would not be zero. However, it would be lower than before. That's simple Law of Demand stuff. It is not necessary to have zero quantity used, just that the new quantity is less than the old quantity used.

That only works if continuity can be assumed.

"However, it would be lower than before."

How do you know? What if the cost of the ban is so low that there is no change in behavior, or the change is too small to detect? If i put a 1 cent tax on booze do you really think that behavior would change so much that you could reliably detect it?

So, you'd have MJ laws similar to those for alcohol? Those've been so effective.(sarcasm) And of course alcoholism is victimless. Not sure what we should do about cannabis, as far as laws go. We need laws restricting the intoxicated from being a danger to others, and we should allow the private sector to have a zero tolerance policy, I think. I don't know if a nuanced approach to legalization is possible/practical. You have a "strong" moral objection to "throw[ing] people in jail", ok. Do you also have a strong moral objection to people who support drug traffickers? How about to people who tolerate people who support drug traffickers? (I ask because just to get a sense of which direction your moral compass is pointing...)

"How about to people who tolerate people who support drug traffickers?"
By giving them a market with no legal competitors, you mean? The kind of market Bill Gates and Thiel can only dream about?

"Do you also have a strong moral objection to people who support drug traffickers? "
By giving them a market with no legal competition?

MJ is spiderman's girlfriend, irregardless how many pottheads try to pretend otherwise. That acronym is taken.

And the name "Donald" is ridiculous if you're not talking about Donald Duck.

(European perspective from 70s and 80s)

The effect of THC is complex. Anxiety can degrade academic performance. It is known that THC induces anxiety. On the other hand THC withdraw symptom also causes anxiety. The effects are opposite.

Thus without differentiating the non or light users from the heavy users the results are meaningless.

"...policy decisions have real consequences, we should know what those are, and I am not convinced that full availability of marijuana is the optimal approach."

Optimal under which criterion? The appropriate criterion for evaluating policy presumably is how well natural rights are protected, given that is the purpose of government [1]. If outlawing the peaceful practice of certain religions was empirically correlated to higher grades, what implications would that have for policy? Policies should have purposes, we should know what those are, and I am not convinced that implicitly changing purposes without explicit consensus is the moral approach.

In any event, now that this (alleged) relationship between marijuana and grades is published, there are several possible consequences:
(1) future would-have-been marijuana users will refrain from using it, thus rendering these research results obsolete (due to selection effects in future samples); (2) future marijuana users will use it anyways, thus revealing that their utility of marijuana use exceeds utility of higher grades; or (3) these results prove unreplicable, calling their predictive power into question. I am not convinced that any of these consequences suggest that full availability of marijuana is not the optimal approach.

[1] Jefferson, Thomas. "Declaration of Independence", 1776.

Well written. Coming back to first principles cuts through Tyler's dilema.

I missed the part when God nominated Jefferson to rule mankind.

"If outlawing the peaceful practice of certain religions was empirically correlated to higher grades, what implications would that have for policy? "

If the deleterious effects are serious enough, then the dangerous parts of the practice are banned, perhaps for everyone or perhaps just for children.

Freedom of religion is one of the core rights that this country is built on, but children of Jehovah's Witnesses will sometimes be given blood transfusions to save their life, over the objections of the parents. Southwestern Indian tribes claim that psilocybin mushrooms are part of their religious practices but even mere possession is illegal in most states.

Now if there's a religious practice that reduces students' grades from say a B+ to a B, no the US isn't going to be banning that. As for substances that have harmful effects, it's even easier to get a majority of Americans to agree that children shouldn't consume psilocybin let alone alcohol and tobacco.

Removing a pastime option increases academic performance? Wow!

Just think of how much grades might go up if we banned alcohol, dancing, video games, TV sports, YouTube, etc.

Tyler is a teetotaler and his credulous analysis smacks of someone who doesn't derive any joy from getting high. (Although the pro-marijuana commenters above are even more transparently defending their self-interest.)

"Although the pro-marijuana commenters above are even more transparently defending their self-interest"
I neither drink alcohol (no member of my family has drinked for the last three generarions) nor smoke nor use any illegal drug and I suport a total ban of alcohol and tobacco and stricter punishmentsmfor people involdpved with drugs, but it is clear Americans just keep making up excuses for their society's failings. One time it is satanic cults, then it is Dungeons and Dragons, then it is pornography, then it is MTV, then it is opioids, then it is Mexicans, then it is Marijuana, then it is videogames. It is time to clean the house.

Have a damn drink then, Thomas.

Never. My father did not drink. His father did not drink. I do not drink.

That's your problem right there.

No, it is not. It is a strenght. Many Brazilian heroes did not drink. Army Marshal Rondon, for example. He spent decades in missions at the jungle and because he did not drink, he survived the harsh environment.

Humbug, you dusky savage! Gin and tonics are necessary in the tropics, you need the quinine to fight off the malaria.

Quinine can be found in perfectly non-alcoholic prescriptions. Also, in most of Brazil, malaria is non-existent. I never knew someone with malaria.

Pish posh, why in damnation would one drink anything non-alcoholic?

Because water rehydrates and soups nourish the body.

it was Dungeons and Dragons though. not sure why they moved on to pornography.

No, it was probably just a game kids played after school.

Oh yeah, because Brazilians never blame anyone for their problems (Portuguese, CIA, climate, banks, etc.)

Evidently, Brazil has many difficulties and life is not perfect, but we never had to invent bogeymen to placate our people, to jusrify our failures. Brazil faced colonial oppression Americans not understand (while Franklin had his press, we were banned from having ours) and exists surrounded by hostile neighbours while Americans never had to fight for their survival as we had for the entire 19th Century. Yet, we do not use the problems we face as an excuse. As president Temer's reforms show, we are much more interested in improving ourselves and our society than blaming others. There is nothing in Brazil like America's moral panics about everything, including but not limited to gays, Mexicans, guns, role playing games, Russians, opioids , marijuana, satanic cults, children, day cares, videogames, pornography, the Emperor of Japan, dirty words, Pokémon and sugar.

In the 19th century, Americans drank alcohol all day long, not just in the evening; thus, the growth of the temperance movement. I expect a similar backlash with regard to marijuana. As for the performance of college students, regular use of alcohol and marijuana is less an indication of immature behavior among the students than an indication of an academic program that is insufficiently rigorous. Students at the Univ. of Chicago who are regular users of alcohol and marijuana will soon find themselves at a less rigorous institution of higher learning.

An alternative explanation for the widespread use of alcohol and marijuana on many college campuses is that it reflects the stress experienced by the students. I attended a state law school (many years ago), the stress magnified by the school's ranking of everyone in the class, one's rank heavily influencing the offers that would come (or not). I rarely drank alcohol (and never used marijuana), mainly because I studied every night except Saturday to keep up (or ahead). After I graduated and worked at a law firm, I got into the habit of the nightly cocktail or two (beer for me) to relieve the stress of work. After a year or so, I returned to law school to study for an advanced law degree, and once again faced the stress of class rank. Yet, I quickly dropped the habit I had acquired of the nightly cocktail or two, the stress of school nothing compared to the stress of work. I suspect the stress felt by today's college students is more a result of social stress than academic stress, the student's social rank more important than class rank (if colleges even use class rank anymore). Of course, everyone responds differently to stress and the causes of it. I find travel to be highly stressful, most likely because the traveler is dependent on others for a safe journey. By comparison, I felt like I was the one in control of my journey through law school

College is consumption, not investment. Think "Animal House" rather than "Goodwill Hunting". It is a government subsidized 4 year (or more) party. MJ use is a feature, not a bug. Learning is a bug, not a feature.

"College is consumption, not investment. Think “Animal House” rather than “Goodwill Hunting”. It is a government subsidized 4 year (or more) party. MJ use is a feature, not a bug. Learning is a bug, not a feature."

In reality, the picture is more complex. Clearly most STEM majors are investing, whereas many students attend classes that don't require much studying aren't investing as much and a few are probably purely consuming.

But it's a gradient. Even in engineering, there will be the occasional student (usually a freshmen or sophomore) who starts skipping homework and class to over indulge in consumption, whether the consumption be drugs, alcohol, video games or a significant other, is pretty irrelevant. But it's a self correcting problem. The student will flunk out in a year.

With an easier degree, it's possible to maintain a higher amount of consumption over investment, but for most degrees at most American universities it's improbable for it to be completely consumption for more than a year. (I'm unfamiliar with universities in other countries.)

College is also about having an 'adulthood trial period', where for many (most?) it's your first time living away from home and not having mommy to do everything for you. This is as important as whatever you learn (or don't) academically. Including learning how much drinking and drugs you can do and still reasonably function.

consumption is the opium of the people Confession is the opium of the pope.

College is consumption, not investment.

About 61% of those earning bacclaureate degrees and 82% of those earning post-baccalureate degrees are following occupational courses of study: business, teacher-training, nursing, information technology, &c. Among those in community colleges, over 60% are earning trade certifications and most of the remainder are hoping to segue to a 4-year school. Among the minority studying academics and the arts, the breakdown is as follows:

Psychology (16%)
Biology &c (15%)
Economics (4%)
Chemistry, Physics, Geology, &c. (4%)
Mathematics &c (3%)
Other (58%)

Psychology has a social research aspect and a natural sciences aspect. The former requires at least some familiarity with statistics, btw.

fuck, Art, you keep a goddamn stack of stats next to your crapper so you can pull them out of your ass on demand, and you don't even have the common decency to drop a citation off with that turd? get your shit together.

I thought one or more graduates of the Univ. of Chicago might appreciate my pun.

You mean Spicoli's not the top student in class? Say it ain't so...

I strongly believe it is morally wrong to throw people in jail for smoking such substances,

You're 55 years old. You can give up the cool dad act, now.

You're laughed at here. You can give up the grumpy old coot act, now. I suppose it's probably not an act.

It's always a shame when those less informed perceive themselves to be the most enlightened :'(

Don't be so hard on Art.

a smoldering fire casts much more heat than light. Art has been smoldering for decades.

>I strongly believe it is morally wrong to throw people in jail for smoking such substances, but still policy decisions have real consequences, we should know what those are, and I am not convinced that full availability of marijuana is the optimal approach.

This is why I love coming here -- to get a glimpse inside the bubble.

It is blindingly obvious to sane people everywhere that unrestricted access to marijuana is very bad thing that hurts peoples' lives.

But for Tyler to point this out he has to hedge, and ludicrously so. He must (1) have a study to quote that no one will ever read or care about (2) must first STRONGLY virtue-signal on the PC opinion that no one can be THROWN in jail (3) cannot possibly opine that legalization is a bad idea.... but only that he is NOT CONVINCED it is OPTIMAL!

And yet this passes for a true Profile In Courage from a coastal economist.

" is blindingly obvious to sane people everywhere that unrestricted access to marijuana is very bad thing that hurts peoples’ lives."
As opposed to even more unrestricted access to alcohol, that has proven to be a boon to mankind...

"It is blindingly obvious to sane people everywhere that unrestricted access to marijuana is very bad thing that hurts peoples’ lives."


Referencing Colorado:

"The son of Nashville's mayor died over the weekend "from an overdose," Mayor Megan Barry and her husband, Bruce, said in a statement.

Max Barry, 22, died on Saturday evening in Denver, said his parents, who according to an official with the coroner's office in Colorado were aware their son was struggling with drug dependency."

That's a powerful anecdote! I guess Colorado is in fact a marijuana crazed hellhole, as this proves.

It didn't say marijuana. I'm not sure overdosing on marijuana is even possible.

Yes, It's an anecdote. I was making the counterpoint that there was a high profile death in Colorado this weekend from a drug overdose. It's contextually relevant to the conversation. I wasn't attempting to refute a study or classify an entire state as a "marijuana crazed hellhole".

As much as you keep harping on Art Deco for his responses, I don't see much difference in this hyperbolic straw man post of yours to many of his responses.

Well, why did you post a non-marijuana anecdote to Anonymous' comment above ("Colorado")? That's not contextually relevant to a conversation about marijuana.

"Well, why did you post a non-marijuana anecdote to Anonymous’ comment above (“Colorado”)? That’s not contextually relevant to a conversation about marijuana."

It's a drug overdose in Colorado. But I grant you not everybody has the intellectual capacity to make the connection.

Dude, we are talking about marijuana. I could post some stats on cigarettes in Colorado, because smoking. But then I'd be wasting everyone's time. If called out on it I wouldn't double down though.

Shit I forgot I wasn't trolling Thiago/Thomas when I posted this.

Guys you are the one's grasping at straws. Marijuana is classed and treated as a drug. It's perfectly fine to point out that marijuana isn't any more dangerous than alcohol and it should be under similar restrictions to alcohol versus much harsher restrictions. But it's ridiculous to compare it with smoking.

But Trolls got to Troll I guess.

Man you are missing my point entirely. In a conversation about marijuana and whether loosened restrictions on it are bad, OJ hyperbolically posts about how it ruins lives, another retorts with "Colorado", obviously meaning that CO has legalized weed for a while and they are doing fine, then you reply about a totally different drug overdose that happened to occur in CO. When teased for relevance, you got snippy. Maybe your comment about some guy ODing in Colorado is useful, but it's still hard to see how it's relevant in this discussion. No one compared it with smoking, I brought up smoking as an equally irrelevant topic to yours.

So, we cool? :-)

Oh yeah, now there you go sounding all reasonable. Yeah we're cool. ;)

Being in prison is bad for grades too.

Also, being in prison lowers post graduation income.... and government income tax receipts too of course.

"It is blindingly obvious to sane people everywhere that unrestricted access to marijuana is very bad thing that hurts peoples’ lives."

Thats a big conclusion based on a single study dont you think?

"It is blindingly obvious to sane people everywhere that unrestricted access to marijuana is very bad thing that hurts peoples’ lives."

You might be either (1) blind, or (2) insane, I can't be sure which though...

Drug legalization can potentially have a eugenic effect by weeding (heh) losers out of the gene pool. Those with strong willpower will breed and the weak will die of overdoses or simply live our their marginal lives childless.

The way they can improve the grade point averages for these students


To introduce a

Drug Studies Program

Where they can all get A's

This study seems consistent with other studies that indicate that heavy marijuana use leads to cognitive impairment. I seem to recall that the Times a while back reported some study showing that heavy marijuana on average resulted in a 7 point permanent IQ drop. Probably very few marijuana smokers as a practical matter risk being thrown in jail so that does not seem like the key issue.

I saw marijuana blunt a lot of students' intellectual ambitions during the 1970s. As Quentin Tarantino says, dope will ruin your ambition, unless your ambition is to get high and watch TV all day.

Does it do so more than alcohol?

blunt? Steve, you're hipper than I reckoned.

"Probably very few marijuana smokers as a practical matter risk being thrown in jail"

You would be surprised. Many, many people are jailed for marijuana use

This, from the Rolling Stone!

I question up front whether TC is only playing with our heads: the RES link he provides does not feature among its forty-one titled papers the paper in question by the authors in question, "'High' Achievers? Cannabis Access and Academic Performance" by Olivier Marie and Ulf Zolitz (orthographic-font apology).

Put off by the misleading link TC offers, I only scanned (and that as briefly as possible) the link to the Vox account, which did seem to allude to the RES study that TC failed to offer the specific link for. A pity that the Vox correspondent, at least, did not see fit to allude to the excellent monograph Understanding Marijuana: A New Look at the Scientific Evidence by Mitch Earleywine (OUP, 2002). Earleywine's comprehensive survey dealt (fifteen years ago, but the chemistry and pharmacology have not changed appreciably since then, even though sample potency levels may have gotten a notch or two more robust in the interim) features Chapter 4, "Marijuana's Impact on Thought and Memory", which the title suggests implicates cannabis chemistry specifically for its ability to impair memory. As Earleywine dutifully points out, any mnemonic impairments subside with discontinuation of use: as the active ingredients are metabolized out in roughly seventeen days and show no ability (on the basis of the research of c. 2002) to impair memory function in the long-term, the ability of cannabis use to impair memory can be mitigated sufficiently for any post-secondary student interested in investigating the frankly intoxicating effects of cannabis products, which otherwise do tend to impair concentration. (As Earleywine sternly counseled: "Anyone planning a public reading of The Nicomachean Ethics should probably avoid cannabis." [p. 74])

The paper is indeed in the REStud:

Thank you for providing the specific link that TC did not provide.

Let's be honest: Americans will always find someone or something to blame for their societal ills: opioids, marijuana, MTV, Youtube, etc. The American system itself is failing and only radical changes will be able to prevent its destruction.

Whereas smart Brazilian's blame themselves for the failing of their society and never, ever try and deflect blame elsewhere or spend their time pointing out the mote in another's eye.

You are comparing oranges and apples. Brazilians, as president Temer's reforms prove, work hard to improve their country. We do not invent bogeyman to justify and excuse the shortcomings our society may have. Such a behavior would be anti-Brazilian. Brazilians believe in civism, personal responsability and indomitable courage. We do not invet excuses, be them RPGs or Mexicans. We work hard to improve ourselves and our society. As a Brazilian anthem says,

"May this rebel song be an unfurled mantle of light

Under the vastness of these skies,

That comes to save us from inglorious deeds!

May this be a glorious anthem that speaks

Of hopes of new beginnings

To inspire with visions of triumph those
who in the future shall come forward to defend it!"

As the anthem of a Brazilian southern state says, "a people with no virtue ends up enslaved

It is really tiresome how Brazil is treatef so shabily here it is truly a mystery. Brazil is beacon to all the nations.

"Ex-President of Brazil Sentenced to Nearly 10 Years in Prison for Corruption"

When exactly did this happen? Oh yes, a few weeks ago.

"“This goes far beyond himself and his political career, which is seriously damaged. It’s Brazil’s reputation,” said Christopher Sabatini, executive director of Global Americans, a research group in New York. “He was a brand. Brand Brazil.”"

"Brazil is beacon to all the nations."

Truly, Brazil is a beacon. Just like every good light house, Brazil warns other nations of the dangers of the rocks upon which it sits. All other nations can then steer clear of those hazards.

1) The imposter wrote it about the beacon. But I support it. It is written:
"Congratulations, O Brazilians,

Already, with virile garb

From the Universe among Nations

Shines brightly that of Brazil.

From the Universe among Nations

From the Universe among Nations

Shines brightly that of Brazil."
2) In Brazil, crime is harshly punished. I can not imagine an American formermpresident being punished. Themrich and powerful can buy their way out. Justice, in Brazil, is not a joke, is not a punchline, it is the backbone of Brazil. It is not a ruse, something to be manipukated by powerful private interests.By the way, how is going the American plan - supported by voters - to "lock her up"?

"By the way, how is going the American plan – supported by voters – to “lock her up”?"

Hillary Clinton was a very smart crooked politician. And you'll note, the US electorate was diligent enough not to elect her to be President..

So that is it? Comey decided she was guilty enough to not be allowed to be president, but innocent enough to not be punished? She will be just be free to spend her ill-gotten money? Well, in Brazil, we believe that we great power comes great responsability. I can not imagine a Brazilian politician remaining unpunished after his corrupt dealings are revealed (also I can not imagine the Russians electing our president, but that is another matter). Also it has been revealed that Mr. Scaramucci used to swear before journalists. I can not imagine an important federal authority innBrazil behaving in such a vulgar manner.

but I admire your commitment to staying in character

Thank you, but I have no merits, I am Brazilian.

Cannabis use in adolescence is believed by many experts to be a risk factor in the development of schizophrenia​ as well as mood disorders like bipolar disorder and depression.

"Many experts" would thus be making severe errors expertly, in which case, and not for the first time.

Adolescent use of cannabis is no more to be encouraged than adolescent consumption of alcohol, but the toxicity of alcohol alone surely impairs adolescent health much more egregiously and cumulatively than cannabis consumption itself can. (I'm no expert and perhaps not a fully-informed amateur, but I have some reasons to suspect that cannabis consumption among adolescents who might otherwise be organically susceptible to the development of "schizophrenia" or mood disorders as profound as bipolar disorder or depression might assist clinicians in DETECTING those predispositions that I suppose arise chiefly courtesy of heredity.)

I'm no expert either. a hallucinagen by classification and can cause psycosis in acute intoxication. Most of the prospective cohort studies show an association between mood disorders and cannabis use, though some do not. I can link to them if you wish (on my phone now so it's hard). Take that for what you will.

Following "Adam Smith" (the late George J. W. Goodman)'s lead in Powers of Mind (1975 or thereabouts), I investigated a bit back in the day. Cannabis even with current levels of potency provides not nearly as profound an experience as even a moderate (c. 200 microgram) dosage of LSD.

Both drugs have been susceptible to a lot of misunderstanding and vilification, even by our trusted experts, just as both have suffered from a comparative lack of critical study: Earleywine cited the sad history of cannabis appraisals as of 2002, I made a case more recently for lysergic acid in this terse essay:

for what it's worth. (I do not class even LSD as a "hallucinogen" for the reasons cited, but I am willing to term both cannabis and LSD as "psychedelics" with the further caveat here that cannabis does not offer nearly as profound an experience.) Both drugs seem to admit to clinical and therapeutic applications, hence neither one properly belongs on the DEA's dreaded Schedule I and both should be removed therefrom by Congressional action, if that's what it takes.

Sure. But there's such a thing as "alcoholic psychosis" too. Basically overdoing it with any mind-altering drug is a bad idea.

Seems obvious to me that is would hurt grades but does not justify keeping drugs illegal.

"Pharmaceutical Freedom"

And there is the Pelzman effect in pharmaceuticals:
The effect of requiring consumers to obtain prescriptions for pharmaceuticals on mortality is examined for a sample of middle-income countries. In countries enforcing the requirement, infectious disease mortality is no lower and poisoning mortality is higher than in those not enforcing the requirement. A broader measure of government intervention—public expenditures on health relative to GDP—is shown to have moderately adverse effects on overall life expectancy.


Do you believe this study? I didn't find the empirics to be particularly convincing. The effects on (average) grades and passing the course are really really small. And if I remember correctly, then the estimator is not consistent. I also doubt that this study would've been published if the results went the other way. Would anyone have believed the results of this study then?

"Our main finding is that the temporary restriction of legal cannabis access had a strong
positive effect on course grades of the affected students. These individuals performed, on
average, 9 percent of a standard deviation better and were 5.4 percent more likely to pass
courses when they were banned from entering cannabis-shops („coffeeshops‟)."

5% more likely to pass courses does not strike me as "really, really small".

It is really really small, and likely just noise.

"In total, we have 57,903 course results from 4,323 different individuals in our main sample who are, over this period, in any of the three years it takes to complete a bachelor‟s degree ...
We find a 4 percentage point increase in pass rates for Non-DGB students when the policy is in place, a 5.4 percent improvement from the baseline pass rate of 74.6 percent. The coefficient on the probability of dropping out is small and not statistically significant. ...
Importantly, the exam results of both groups of students clearly trace each other up to the period when the Non-DGB students are no longer allowed to buy cannabis in cannabis-shops. This is a good illustration of the common pretrend assumption which is necessary to validate our difference-in-differences approach. After the policy introduction, Non-DGB students appear to suddenly do much better than their DGB peers, which is a first hint that the policy might have had a positive effect on the performance of those who could no longer buy cannabis legally. "

Those are large enough numbers (4,323 students taking 57,903 courses) that a 5.4% increase in pass rates seems significant. Particularly since it's both an improvement across a clear time division (when the policy was enacted) and against a non-affected peer group (the Dutch-German-Belgium students).

A 9 percent of a standard deviation increase is a very small number. Dutch grades are on a scale from 1 - 10, 1 being the lowest and 10 being the highest and 6 being a pass. Almost all grades are either 5,6,7,8. Other grades are hardly ever given. The standard devation is a little less than 1. A 9 percent of a standard deviation increase is therefore an increase of 0.09 points. A 6 becomes a 6.1 at most.

Now ask yourself the following question. How big is the difference between someone who received a 6.1 and a 6 on a test out of 10? Or how big is the difference between someone who received a 8 and a 8.1 on a test out of 10? It's not a very big difference. In practical terms marihuana consumption is irrelevant for grades.

Regarding the pass rate a 5.4 increase in a very high pass rate given this small average difference tells you only that approximatel 5% of the students were borderline. How big a difference is there between a student who just passes and who scores 0.1 points less than the student who passes? In practical terms this is again not a very big difference. We could just as well treat the students on both sides of the threshold as identical to measure the effect of having a piece of paper stating that they passed the course.

This is of course if the estimated effect of the policy is the effect of the policy. The parameter estimate is much stronger evidence for that the paramater is equal to or larger than smaller values than the estimated effect. It is very strong evidence that there is a difference of at least an epsilon from the null hypothesis. The evidence is a bit weaker for a difference of at least two epsilons etc.

Now look also at the graph in the article.

Three things stand out:

1. Without this policy both groups scored much lower in 2003 than with this policy.

2. The grades of the DBGs (and the non-DBGs) follows a relatively regular up and down pattern. The period of the policy just happens to coincide with a down pattern for the DBGs. A comparison within the DBGs therefore doesn't make much sense.

3. There is an upward trend to the grades of the non-DBGs and the DBGs with a stronger upward trend for the non-DGBs.The lows after each peak become higher.

The first point indicates that other aspects seem to be much more important than this policy. The second and third point indicate that the groups are pretty much where you'd expect them to be without this policy. This is consistent with the fact that the estimated effects are very very small.

Finally, the statistical evidence is weak. Go and look at the econometrics and ask yourself whether you'd believe this study if the results had gone the other way. Would you have believed a study using the same setting and methods that found that student performance increased with marihuana access?

Two more points.

One, note that the average grade of the non-DBGs is close to the threshold of not passing is a 5.5 is considered a pass and below the threshold of passing if 6 is a pass. This is a problem! Students are not happy when they don't pass. And neither is the administration. Different or better (self-)selection of students is then the result (this can explain the upward trend).

Two, note that the period of the policy coincides with high unemployment in non-DBG countries. It might be very attractive then for non-DBG students to go to DBG countries to find employment or to study there to find employment instead of remain at home. It might also be attractive for non-DBG students to focus more and party less as the cost of lower grades (higher probability of unemployment at home) increased.

Both points suggest that the student population of the non-DBGs changed as did their behavior.

I predict a doubling down of discrimination by elite college against Asian students, as sober the children of the Tiger Mothers further out compete the stoned children of the meritocracy.

The literature on substitute-compliment between the drugs has found that cannabis is a complement for tobacco, and substitute for alcohol and opioids. The story seems to be one that cannabis is as the third drug of the masses. Use rates for marijuana have been a clear third by a wide margin since reliable measurement has been done. Absent oppression, the demand isn't going away. Market data from legal states has added credence to theories that the long run cannabis market being dominated people use legalized edible and oil products to combat pain and anxiety. The median cannabis user in the medium run is less a college student than a 35 year old mom lugging her kid around or factory worker vaping after work because beer has too many calories. This transition is only possible with regime certainty that legalization brings. Professionally made edibles with reliable dosages are innovation in the market that helps mitigate the notorious dosage uncertainty for the first time. E-cigarette style oil vaporizers only make sense if one can reliably buy refills. None of this is in place in the Netherlands, as such, the study's usefulness is limited by looking at what is a mature market, but one without qualities indicative of the most likely future market.

There's a Scottian story here. While indoor grows are ubiquitous in the legal market, the bulk the US and world's production is outdoors, in remote areas. Legalization, and the economies of scale it brings, is least costly the means of control when the market has long been dominated by people at the margins of society. These people aren't reigned in by any regime that limits availability when the market is as large as it is. It's as close to a cash crop as hill folk in many places have. For all its other merits and demerits,

I wonder what the percentage of commentators here have actually ever indulged in cannabis. I am going to say far less than 30%.

They don't test for the pre-trends. In this day and age, this is unbelievable - this is the REStud? I'm flabbergasted.

Getting nazi in there Tyler: reducing entertainment options by force law to increase the students grades?

In other news, Frito Lay announced an uptick in sales to the Dutch market, especially in its Doritos brands.

The homeless population in my town are getting very bad marks with their chronic K2 use, which fortunately they conduct in front of the police and EMS stations, so that saving their lives is all in a day's work for those folks. As I understand it, K2 is marijuana - or some other plant - sprayed with extra cannabis sauce.

But perhaps that is a completely different category of thing.

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