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On a talkshow this morning during a discussion of the validity of random drug tests a member of the Illinois State Police stated that 70% of admitted Marijuana users also admit to using while at work. I am not finding any studies or statistics that back this up or refute it.

The claim was used to support the requirement that teachers be subject to random drug testing. That claims of what is done at home stays home is most often not true. I had not originally included this part as my skepticism is about the usage at work not about the effectiveness of drug testing.

Sklivvz
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Chad
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  • Would it be appropriate to consider this a [united-states] question? – Sklivvz Aug 18 '11 at 13:33
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    @Sklivvz - Is there some reason it should be? I do not have anything against it if it really matters. – Chad Aug 18 '11 at 14:11
  • In Canada I've encountered many people who were smoking _Mary-Jane_ on-the-job. I also once worked at a company where I was one of the only two employees who don't smoke pot at all, and the company had a strict policy of "no drug use during business hours" which everyone actually respected. So, based on my own anecdotal experience, I think it would be difficult to know for sure without a study that involved a large number of subjects [who were willing to admit to smoking pot (which I suspect could be more difficult to find in the USA due to strong anti-drug efforts by authorities there)]. – Randolf Richardson Aug 18 '11 at 17:20
  • @chad, It's just that different drug laws will yield different outcomes, probably. Also the police agent probably cited a US specific stat. – Sklivvz Aug 18 '11 at 17:46
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    @Sklivvz - I do not know that I agree with that. But I have updated it to include the US tag. Though that may be an interesting stat to see, the percentage of people who use Pot at work in countries where it is legal/not legal. It would also be interesting to see the number of selfidentifiers vs actual users. – Chad Aug 18 '11 at 18:21
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    does musician count as an occupation? If so.... – Monkey Tuesday Aug 18 '11 at 19:06
  • @Chad do you remember what the talk show was where you got the original data? – Monkey Tuesday Aug 18 '11 at 19:08
  • [WMBD](http://www.1470wmbd.com/) morning radio show. It was part of a story about a teacher strike over random drug testing. – Chad Aug 18 '11 at 19:59
  • I had a job when I was young where it was required to partake, no joke. – Moab Aug 20 '11 at 03:56
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    Admitting to "having used while at work" is a little different than "(routinely) using at work". It seems plausible that 70% of pot smokers may have used at work _some time in their life_--like while they were in high school, and worked at McDonald's, but may not use at work now that they're 30-something and have a real job. – Flimzy Aug 20 '11 at 04:25
  • @Flimzy - I totally agree. My thought was there would be some research out there that would clear this up but I am wondering at this point if the officer made up the stat or if he was given infomation with a made up stat. – Chad Aug 22 '11 at 12:58
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    Two things are being confused here. "Admitted user" is different than "user". Admitted users are going to be a smaller percentage of total users. So while your question says 70 percent of "users", the actual claim you quote is seventy percent of admitted users. Also reading the statistics, it's not clear which form of "admitted" is meant. Studies often cite "admitted" as "admitted for medical care" as opposed to "admitted to using". I updated the question to match the claim, but the use of admitted is still unclear. – Russell Steen Aug 22 '11 at 23:04
  • @Russel the inference was that this subset was an accurate representation of the whole of all users. While debunking the claim would certianly debunk the whole it is the whole that is most concerning. – Chad Aug 23 '11 at 13:15
  • @Chad -- If we're changing the claim to make it more interesting, then we're not debunking anything. Also disproving the claim does not necessarily disprove the whole (or vice versa) as a subset of a group can always have an anomaly that does not represent the entire group. And again with the use of "debunking". Debunking is ridiculously over-used as a term and reflects a general attitude of disdain for opposing viewpoints. – Russell Steen Aug 23 '11 at 15:05
  • @Russel - The claim inferred that because 70% admit to using at work then a similar number can be assumed in the group of not admitters. Thus if you can show that the 70% of the admitters is not a real stat then the inference is broken. Alternately you can show that it is not 70% of the whole and break the inference as well. I am not changing the claim just clarifing the context. The only purpose for citing the claim was to infer that it is true of all users. If this claim is going to be used to back up the spending of tax money i pay into I would like to know if it is true. – Chad Aug 23 '11 at 15:44
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    A thorough definition of "admitted Marijuana users" from the police may help. The sample the police have the potential to survey is going to be significantly different from a survey of the general population. There's fair chance "admitted Marijuana users" refers to those who admit it to the police when they're busted for something. Either way, there are issues of selection and perception bias, and I think the talk show is using an argument to authority to attempt to make a political point. – ThisGuyKnowsCode Aug 23 '11 at 15:57
  • I think this really depends on how you define using. Some just toke up before they go into work and then re-up when they go to lunch. Others, more common in the service and repair industries, have a work environment where everyone smokes, so they smoke enroute to a worksite or in the freezer or dumpster area. – Mark Rogers Jul 05 '12 at 14:46
  • @MarkRogers - I am not contesting that some people smoke pot at work. But I think there are far more casual (on the weekend/special occasion) users that would not fall into this category. But maybe I am wrong. Either way looking for proof one way or the other. – Chad Jul 05 '12 at 14:54
  • @Chad - I would guess that you are right, I think most people who smoke pot, do not do so at work. – Mark Rogers Jul 05 '12 at 15:30

2 Answers2

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While this doesn't prove that the hypothesis "70% of marijuana users also use while working" is false, it certainly makes it look unlikely.

http://www.icpsr.umich.edu/quicktables/quicksetoptions.do?reportKey=23782-0001_du%3A7

Using data from this site, I was able to come up with the following table. This represents employed (both full-time and part time) people who say they have ever used marijuana, and how frequently they have used over the last 12 months:

77.2% have not used at all in the last 12 months
6.5% have used 1-5 days in the last 12 months
1.5% have used 6-10 days in the last 12 months
2.7% have used 11-25 days in the last 12 months
3.6% have used 26-100 days in the last 12 months
8.4% have used 100+ days in the last 12 months

If we only consider the "recent" users (excluding the 77.2% who have not used in the last 12 months), we are left with:

28.5% have used 1-5 days in the last 12 months
6.7% have used 6-10 days in the last 12 months
12.0% have used 11-25 days in the last 12 months
16.0% have used 26-100 days in the last 12 months
36.8% have used 100+ days in the last 12 months

If this data is accurate, for 70% of current marijuana users to smoke at work, then even a good portion of even the most casual users would have to smoke at work, and that just seems unlikely. I suspect the most casual users are the least likely to smoke at work.

So I would argue that for any useful meaning of statistics, it is clear that 70% of pot users do not use while at work.

Of course, by massaging the numbers sufficiently, it may be possible to claim that 70% of people who have used at any time in their life, used at work at some time in their life--or more likely were high at work (used immediately before arriving to work, or over their lunch break, etc). But using such a statistic for anything other than curiosity, I would consider unethical, considering that 77% of "some time in their life" users no longer use at all, according to this data.

Flimzy
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    Good answer. In other news: 100% of potheads that smoke 20 joints per day, also smoke at work... :-) – Sklivvz Aug 22 '11 at 14:55
  • Regardless of the fact that this can't discredit the original claim, these are certainly much more 'telling' statistics - and if anything point out just how weak and meaningless the original claim is. Besides, "the Illinois State Police" isn't exactly a reputable statistics office. – Alain Aug 23 '11 at 13:29
  • @Flimzy - I do not know that you can draw those conclusions from the data here. Its possible that all of the use by those doing it 1-5 times happened while at work or went to work while still high. While I agree that only those that have been active in recent times really matter as far as this goes. So having smoked at work one time when you were young is different from smoking now. I fall into that I did when i was young catagory. But I am certian that if I still smoked now I would probably smoke at lunch... sure would make the afternoons better :p – Chad Aug 23 '11 at 13:49
  • @Sklivvz: Wait, how many of those 20-joint-per-day potheads work? – Oddthinking Nov 07 '11 at 00:55
  • @Oddthinking is there necessarily a 100% correlation between smoking pot and being out of a job? Let me give you an example: rock musicians. – Sklivvz Nov 07 '11 at 07:51
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    @Sklivvz, doesn't your original quote assume 100% *IN* work? – Oddthinking Nov 07 '11 at 08:29
  • @Oddthinking it was meant in the same sense as the OP, but more explicitly: "an extremely high proportion of heavy pot users who are employed, also use at work, because heavy usage means continual intake of the substance." – Sklivvz Nov 07 '11 at 08:43
  • @Sklivvz - I think that last use is kind of irrelevant. If I smoke pot one time in a year but it was yesterday I show up in the first group where a regular user who is waiting on his supply could be in the second or third group. I would want to see numbers from those that classify their use in the daily, weeky, monthly, and occasionally categories. The inference was clear that this was supposed to be people who use regularly also regularly use at work or are at least affected by the drug while working. If this is true then it supports the theory that drug testing protects the employer. – Chad Nov 08 '11 at 15:22
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For the total user population, 70% cannot have used marijuana in the workplace. I derived from table 2.11 on this paper to find that 33.6% of marijuana users aren't even employed. So if 33.6% aren't employed it can't be true that 70% are using at work.

33.6% is reached by using the 2009 data on millions of users (NOT the rate of use in past month chart) graph here. Unemployed + Other + Full Time + Part Time/ Unemployed + Other. The other column is people who are not in the workforce, but not unemployed.

(9.2+3.6+2.5+4.0)/(2.5+4.0) = .336

Table of users

However, the actual claim in the show could still have been true. The likelyhood is that the officer was just quoting a study. Since the vast majority of studies use "admission" to mean admittance to a medical facility (which is the standard definition used in medical research) and not admitting to use, then 70% could easily be an accurate number. People who are admitted to a medical facility for abuse are going to be centered towards the most severe and frequent users and would not represent the general population. Indeed, almost 30% of admitted users were referred by their employer, so the number of admitted users that use at work could realistically be within 70% (no this doesn't show it, but it does show that 70% isn't a wild crazy made up number).

Russell Steen
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  • That 33% are not always unemployed. And the figures actually show its around 20% not 33%. And looking at your reference it appear about 7% of the adult population use marijuana. So only 5-6% would need to use it for the claim to be valid. – Chad Aug 23 '11 at 20:25
  • @Chad -- No, the CDC clearly has MUCH more than 7% of the adult population using marijuana. You're looking at percent used during the past month which is a different number than total % of users (who may only use a couple of times a year). The figures show 33%. If you can get 20% show your math. – Russell Steen Aug 23 '11 at 20:27
  • The other column does not count as unemployed just because they do not have conventional jobs. So it is actually less than 20% closer to 13% – Chad Aug 23 '11 at 20:31
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    @Chad -- Did you even click through and read? From the paper: The Other Employment category includes retired persons, disabled persons, homemakers, students, or other persons not in the labor force. What part of "persons not in the labor force" is unclear? It's standard to leave the groups mentioned there as something other than Unemployed, because unemployed is generally used to mean "looking for work, but not getting it". – Russell Steen Aug 23 '11 at 20:35
  • I disagree but its irrellevant. Just because it is unlikely that 20% of the total workforce has used pot at work in the last year does not mean that it is not happening. – Chad Aug 23 '11 at 20:38