How to demolish a phony number: Kilmer on the marijuana crop

Beau Kilmer demonstrates how to drive a stake through the heart of a made-up figure.

Watch, and Beau Kilmer will show you how it’s done: you keep smiling, and you keep your knife so sharp that the number you’re killing doesn’t even feel it going in.

Jon Gettman is a marijuana-legalization activist with a Ph.D. from George Mason University. He made up the statistic that the value of the annual U.S. marijuana crop is $36 billion, which is off by roughly an order of magnitude. (Activists and drug warriors share the habit of wildly inflating  drug-related numbers.)

When Michael Montgomery of the California Watch project of the Center for Investigative Reporting asked Gettman about the calculations in our marijuana legalization book that blew his estimate out of the water, he replied, more or less, that the problem was our failure to get adequately stoned: “Non-using analysts are woefully ignorant about marijuana consumption amounts or practices,” he huffed. But by the time the ABC Bay Area affiliate got to him, he had decided to change the subject:

The issue here is not the dollar or the production amount, it’s the issue of drug control. Under the current  policy, drug control is a fallacy.

In other words, “Yes, I made up the number, but I’m on the side of the angels.” [The TV reporter describes this as Gettman “standing behind his research.”  For “standing behind” read “backing rapidly away from.”]

Another activist and author, Ed Rosenthal, decided to take refuge in ignorance, describing the controversy as two blindfolded men throwing darts. But neither one tried to deal with Beau’s simple calculation: to believe Gettman’s numbers, you’d have to believe that the average person who smokes pot at all smokes twelve joints a day.

Come to think of it, Gettman may be right: some numbers make more sense if you’re thorougly wasted.

Update See Keith Humphreys’ guide to DIY pot-market calculations.



Author: Mark Kleiman

Professor of Public Policy at the NYU Marron Institute for Urban Management and editor of the Journal of Drug Policy Analysis. Teaches about the methods of policy analysis about drug abuse control and crime control policy, working out the implications of two principles: that swift and certain sanctions don't have to be severe to be effective, and that well-designed threats usually don't have to be carried out. Books: Drugs and Drug Policy: What Everyone Needs to Know (with Jonathan Caulkins and Angela Hawken) When Brute Force Fails: How to Have Less Crime and Less Punishment (Princeton, 2009; named one of the "books of the year" by The Economist Against Excess: Drug Policy for Results (Basic, 1993) Marijuana: Costs of Abuse, Costs of Control (Greenwood, 1989) UCLA Homepage Curriculum Vitae Contact:

17 thoughts on “How to demolish a phony number: Kilmer on the marijuana crop”

  1. Huh. Beau Kilmer says that in order for $36 billion to be a plausible estimate, each reported past-month user would have to had smoked roughly 12 joints a day for the entire year.

    As per NSDUH 2010, there were an estimated 17.4M past-month pot users. So 17,400,000 x 12 x 365 = 76,212,000,000 joints annually. So the effective price per joint in order to sum up to $36 billion is 47 cents, which works out to, assuming a gram a joint, $13.32/oz. The numbers indeed don’t add up, but so far, it’s not Gettman’s which don’t.

  2. You forgot to include imports, which are the majority of the market, and that this is the farmgate valuation, not retail.

    1. The news VO says “…statistics we often hear repeated is that marijuana is a 36 billion dollar industry, bigger than…”. But if Kilmer was talking of just farmgate revenue from present domestic crop production then the reporting could have been more clear. Of course, if marijuana were nationally legalized and priced so as to curb the black market then the Mexican supply would presumably be replaced by American crops.

      1. Jon Gettman’s report specifically refers to marijuana grown in the United States. From his report:

        “1) Marijuana is the largest cash crop in the United States, more valuable than corn and wheat combined. Using conservative price estimates domestic marijuana production has a value of $35.8 billion.”

  3. In other words, “Yes, I made up the number, but I’m on the side of the angels.”

    As the prophets predicted, the Jon Gettmans and the John Walters’ of the drug policy world shalt fuse into one dread being

  4. Excerpt from Kym’s article:

    “Recently, Humboldt Co. Sheriff Mike Downey showed me a roughly 10 mile square map of Redwood Valley, an area in the eastern part of the county. On it were plotted 93 gardens that the Sheriff’s Department. had located though not raided in 2011. Downey estimated that around 70 of those gardens were large sized—a number he defined as more than a couple hundred. To make the math easy, let’s say that 50 of those gardens had 500 plants for a total of 25,000 plants in this 10 mile square area. Now, Humboldt County has more than 3500 square miles. Let’s make the ludicrously conservative assumption that only 1/100 of those square miles have the same level of production as Redwood Valley-35 square miles. 35 x 25,000 equals 875,000 plants grown outside in Humboldt every year (remember, this is a conservative estimate.)

    Let’s say those plants average one pound each (The average weight will probably be much more but let’s be conservative.) 875,000 pounds of pot grown outside in Humboldt every year. Let’s say that most of these plants get an average price of $1200 per pound (yes, I know that is a conservative estimate also.) $1200 x 875,000 equals over $1,000,000,000—over $1 Billion dollars grown outside in Humboldt alone. This does not take into account indoor, of course. And, of course, it is an extremely conservative estimate of how much is grown outside here.

    Let’s say Mendocino grows an equal amount (though estimates I’ve heard put them at growing more.) That would mean that according to the authors’ estimates, Humboldt and Mendocino grow at least half of the marijuana purchased in the United States….

    Now, of course, the flaw in this equation is that we are relying on numbers from law enforcement which has a vested interest in large numbers. They could be inflating the numbers (though I don’t think they are as the information correlates with what I see on the ground.) So, let’s just cut the number in half. Now Humboldt and Mendocino are producing at least 1/4 the purchased marijuana in the entire nation…

    Now, I’m a big booster of marijuana from the Emerald Triangle but there is no way that these two small counties grow a quarter of the marijuana bought in this country (remember we haven’t even included Trinity, Shasta, Sonoma, and Lake Counties not to mention Colorado, Oregon and Washington.) The reality is that the numbers the authors have put forward must be wrong. The amount of marijuana purchased in the United States must be much, much higher than they have proposed. How much higher? I don’t have the expertise to know but my guess…Cannabis is still the cash king.”

    1. Aside from all of the really shaky estimates going on here, starting with the sheriff estimating the number of plants (because law enforcement officials have *never* inflated their estimates of drug statistics), Kym has a math error in the first paragraph you quote. The “35 x 25,000 equals 875,000” equation is derived as if there were 25,000 plants per square mile, but the 25,000 plant estimate comes from an area 10 miles square.

      It goes on from there. He estimates the weight of each marijuana plant at one pound and then implicitly assumes that the entire weight of each plant becomes usable pot. That’s ridiculous. It also doesn’t include the fact that some of the plants are male.

      Taken as a whole, you’ve thrown up some absolutely meaningless numbers that serve mostly to discredit the source as at all useful.

      1. Kym’s a woman.

        The HumCo Sheriff’s photos are pretty easy to use to derive estimates of plant numbers (poke around on Lost Coast Outpost and you’ll find a slideshow of similar ones).

        Your point about the math error does look right to me, let’s see whether Kym agrees she got that wrong or just wrote it wrong.

        Re poundage, you clearly have no idea what you’re talking about. And no, none of the plants are male. Zero.

        1. Re poundage, you clearly have no idea what you’re talking about.

          All I’m doing is using her own figure: “Let’s say those plants average one pound each . . .”

          If she means something other than that the plants weigh one pound, then she should say so.

          1. Sorry JMN, I apologize for being a snarky ass, but in context (and in this community) it’s clear we’re talking about pounds per plant of trimmed bud from well-tended outdoor gardens (1-3 lbs/plant as a rough estimate). Largest in my direct knowledge was in excess of 12 from a single plant, but that’s not a smart way to grow.

            Meanwhile, Kym’s copped to the error you caught, but raised other analyses that I was gonna bring up:

            “UPDATE 1:33 PM: I made an error in my math calculations in the article below. Instead of saying 1/10th of the land in Humboldt produces the same amount of pot as Redwood Valley, I said 1/100th. So even though I’m perfectly comfortable with the figure that would result from that, let’s just scrub this piece and look at some other facts.

            According to Jennifer Budwig, a local banker who has written a paper on this, says about 200,000 plants are seized in Humboldt Co. annually. Law enforcement thinks they get about 1 to 2% but to be safe, she said, let’s say they get 10% or 2,000,000 plants are grown in Humboldt. Then, for various reasons, she estimates 28 percent of pot grown is indoor and 72 percent is pot grown is outdoor. She uses another conservative estimate to figure out how much pot comes from each plant. But she basically says,

            Indoor is 1 lb. per 10 plants x 3 harvests per year at $2,500 per lb.

            168,000 plants = $420,000,000

            Outdoor is 1 lb. per plant x 1 harvest per year at $1,500 per lb.

            1,440,000 plants = $2,160,000,000

            And she comes up with the big number of $2,600,000,000. Yes, that is 2 billion, 6 hundred million in Humboldt Co. alone. Way bigger than the 1 billion I offer as the conservative number below.

            But, there are other numbers that we could look at also. For instance, the Campaign Against Marijuana Production figures here say that in 2010 over 4 million plants were seized by them in California (not by anyone else such as local sheriff’s departments so a lot more was gathered that year.) Even if we say that each plant is only worth $250 because we don’t know how much is indoor and how much is outdoor (though we could easily surmise that as it is CAMP that most is outdoor and most would bring in a minimum $1000 per plant) the resulting amount seized is worth $1,000,000,000—one billion dollars. Matching this up against these authors’ estimate, CAMP — working in California only — seized something between a quarter and half as much pot as eventually made its way to market throughout the nation. Heck, by CAMP’s own account it doesn’t even seize a quarter of the pot produced in California.

            I understand that unless you live in a pot producing area, the numbers of pounds produced can seem unbelievable. In fact, those of us who live here are often astounded but as a grower I talked to told me—nearly 80% of the people on his block grow indoors. In rural watersheds, the percentages of residents growing are often closer to 90% and some of them are really big growers responsible for 1000’s of plants or 26,000 like the Hoopa bust below. With those kind of numbers, a billion dollars seems incredibly small to come from our county. And, 4 billion produced in the nation seems impossibly small.”

  5. NSDUH usage rates are almost certainly underreported, with some states probably underreporting more than others depending in part on the social acceptance of marijuana use in each state. (That’d probably be an interesting thing to try to model.) Assuming Gettman’s underreporting rate of 25% is close, 12 joints becomes 9. This is still far too many to be plausible. Plus, 1 gram per joint might actually be a bit high, especially because heavy users often smoke probably less than 0.5 grams out of a pipe or bong per session.

  6. Scott, I’ve personally been in gardens of over 500 plants all of which were going to produce 8 to 10 lbs of manicured bud.

    JMN, I tend to believe that 1 lb. of manicured pot per plant is on the low side for outdoor but use that number because it is conservative and because it is easy to do the math (apparently not my forte as to my embarrassment I found today.) To the Humboldt Community that I write for it is understood that the weight you care about on a plant is what you can get paid for but I should have considered that there might be out of the area people reading this particular post and been more clear.

    Scott is right, nobody goes to the trouble of digging a hole for a male. Occasionally, one or two will slip through but effectively almost none are seized by law enforcement because usually law enforcement doesn’t tend to raid until long after a grower would have discovered the horrible mistake of planting a male and ripped it out.

    I’ve just finished reading Kilmer’s paper (Kilmer, B., et al., Bringing perspective to illicit markets: Estimating the size of the U.S. marijuana market.
    Drug Alcohol Depend. (2011), doi:10.1016/j.drugalcdep.2011.08.008) on how he came up with the numbers. I do find the numbers impressive but like Scott says, I can’t reconcile them with what I see on the ground. I write for High Times and spend a considerable amount of time in people’s gardens photographing and taking notes. I live in a community–Southern Humboldt—that lives or dies by the amount of money that comes in from cannabis. I can’t reconcile those small numbers that Kilmer asserts with the amount of marijuana I see everyday flowing out of this area. We either produce 90% of the cannabis out there (unlikely) or there is something very wrong with his numbers.

    As to cops lying about the numbers of plants, I’ve never talked to a large grower that has been busted but the smaller growers generally agree with law enforcement’s numbers on the amount of plants they had within about 10% nowadays though that was different 20 years ago.

  7. If the value of the marijuana crop were $0, and the tax that could thus be levied on it were also $0, it would still be worthwhile to legalize marijuana on libertarian grounds and to save the money and human lives that we spend enforcing the current laws. So arguing about the value of the crop would appear to be pointless. Nonetheless, if we’re going to do so, we should use good techniques.

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  9. What I find curious is the victory dance when public policy is on the line. Sure, I get it, but both the Keimans of the world and the NORML folks agree, to an extent. (to boil it down to a slightly absurd oversimplification, pot is less harmful than alcohol, which indicates that our laws and policing are out of whack in one direction or the other.)

    But sure, let us all please continue talking about numbers that do not exist in the real world.

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