Comments on: Even real drug problems get hyped

By: Bargain Countertenor

Bargain Countertenor — Mon, 19 Jun 2006 17:11:00 +0000

Daksya,
The short answer to your question (How can you know RRT is providing better answers) is you can’t.
The only way you can tell is to have some alternate source of information. When the question of RRT’s accuracy has been examined, it has usually been found to be better than direct questioning. It’s not perfect, but it IS (usually) better.
BC

By: serial catowner

serial catowner — Sun, 18 Jun 2006 17:08:12 +0000

The RRT sounds like a clever test that pretty much makes it immaterial how worried the respondent is about answering the questions. If I’m reading this right, false negatives should be screened as well as false positives.
This is good for estimating rates of use, etc. However, in my rural county the ability to detect “drug use” by probationers is so good that some of them actually ask to be allowed to serve their time- being on probation year after year, when the original sentence would have been six monthes, makes no sense to them. Nor does it to me.

By: Bernard Yomtov

Bernard Yomtov — Sat, 17 Jun 2006 16:05:31 +0000

Jadagul,
Thanks. That’s how I understood it. I think the objection I was raising is the same as Brett Bellmore’s. Rational or not, suspicions will be there.
Another problem is this. BC writes that he used the procedure in a “methadone maintenance program that was required to ask if the clients had used illegal opiates in the previous week.”
I take that to mean the same people were surveyed weekly. That makes it possible to calculate how likely it is that the client had in fact used opiates at some point.
I’m sure this problem, like false responses, is well recognized. I wonder how they are dealt with.

By: Brett Bellmore

Brett Bellmore — Sat, 17 Jun 2006 11:49:59 +0000

The simplified problem is that people who face the prospect of criminal sanctions if they are found out have no incentive to take the chance that there’s some trick involved that they don’t quite understand.

By: Jadagul

Jadagul — Sat, 17 Jun 2006 10:12:13 +0000

Bernard Yomtov: the idea is that we can’t figure out who, specifically, is confessing to drug use. A simplified version of the procedure would be this:
I give you a questionaire with ten questions. For each question, you flip a coin. If you get heads, you answer “yes” to the question. If you get tails, you answer the question honestly. You can answer the question “yes” safely, because I don’t know who’s used meth (or whatever), and who just got heads on the coinflip. But since we know the distribution of heads and tails, we can disaggregate the data and figure out what percentage of people said they’ve used meth.
The problem with this method is that you need more than double the sample size to get equally good results—double because only half your sample answers the questions, and less because there’s additional imprecision from having the random coin-flip factor in there (you won’t get exactly 50% heads). But it removes a major disincentive to answer honestly, and so generally improves truthfulness.

By: daksya

daksya — Sat, 17 Jun 2006 00:14:25 +0000

BC , thanks for the cites. I’ll look RRT up. Still, I must ask: how will one verify that RRT is providing more accurate answers? Alcohol prevalence can be roughly compared with (legal) sales inventory. There’s no such stable, reliable reference for illegal drugs.

By: Bernard Yomtov

Bernard Yomtov — Fri, 16 Jun 2006 23:31:03 +0000

BC,
Maybe I don’t fully understand the procedure, but it looks like it still requires the respondent to trust the enumerator, and the entire system. If I were doing something that could get me sent to jail I might not be that trusting.

By: Bargain Countertenor

Bargain Countertenor — Fri, 16 Jun 2006 23:27:16 +0000

Actually, I checked my files at home and found these cites:
Tracy, Paul and Fox, James 1981 The Validity of Randomized Response for Sensitive Measurements. American Sociological Review 46:187 – 200.
(My summary)
Tracy and Fox used RRT and direct questioning to ask about self-reported arrests in a household survey. They then compared the response with police arrest records, and found that RRT outperformed direct questioning. The RRT estimate was found to have smaller mean squared error than the direct question estimate.
Goodstadt, Michael and Gruson, Valerie. 1975 The Randomized Response Technique: A Test on Drug Use. Journal of the American Statistical Association 70:814-
(My summary)
Goodstadt and Gruson used a bifurcated survey that used either RRT or direct questioning about drug abuse in a population of high school students. They found that RRT reduced the refusal rate and produced significantly higher estimates of drug-use rates. They conclude that direct questioning results in underestimated incidence of drug-use.
Shimizu, I and Bonham, G 1978 Randomized Response Techique in National Survey. JASA 73:35-39.
(Author’s abstract)
The randomized response technique was used in the 1973 National Survey of Family Growth to produce estimates of the number of women having abortions during a 12-month period in the conterminous United States. The model applied used two unrelated questions in separate half-samples, with a coin as the randomizing device. While the technique resulted in a higher estimate for the number of women with abortions than has previously been obtained through direct questions or reporting systems, it also yielded divergent estimates of abortion from the two half-samples. Possible causes for this divergence are discussed.

By: Bargain Countertenor

Bargain Countertenor — Fri, 16 Jun 2006 23:06:06 +0000

Randomized response methods are in most modern sampling textbooks. It’s typically used in small scale surveys that are after sensitive data. The application that I know best was its use in a methadone maintenance program that was required to ask if the clients had used illegal opiates in the previous week.
In principle there is no reason that you couldn’t use the method in a large scale survey that involved face-to-face interview. There are training problems for the enumerators, but they aren’t horrible.
As far as non-response rates go, one of the reasons for going to randomized response methods is to reduce non-response. It won’t eliminate it, just as it won’t eliminate false responses to the sensitive item. But it does usually reduce both.
The other drawback of RRT items is that you can’t do logistic regressions or discriminant analyses on them. The mixture distribution destroys the information you need. You also have to be very careful about slicing and dicing the results.
When I’m back at the office next week I’ll see if I can find a couple of cites. I can’t access my search tools from here.
BC

By: daksya

daksya — Fri, 16 Jun 2006 20:46:30 +0000

Bargain Countertenor – can you point to an illustration of this technique? Also, your technique can’t take care of the non-response rate (typically 20-25%).

By: Bargain Countertenor

Bargain Countertenor — Fri, 16 Jun 2006 15:43:43 +0000

Actually, estimating the prevalence of a socially stigmatized trait is a manageable problem. Statisticians have had the methodology available since the mid-1960s.
The methodology is a randomized-response survey. On sensitive items, you have alternative versions of the question. One version is innocuous (Are you awake now?, or Did the coin show heads?) and one is the item of interest (Did you use meth yesterday?) The keys to the technique are:
1. The respondent uses some sort of randomization method to decide which question to answer.
2. The randomization procedure has a known probability of selecting each version of the question.
3. The innocuous question has known probabilities for its possible responses. The easiest way is to make P{Yes} = 0 or 1.
4. The enumerator does not know which version of the question is being answered; the respondent understands that her answer is not tied to a particular version of the question; and hence, no one can figure out if she was telling the enumerator that she used meth yesterday.
Now, even though the status of any individual respondent is unknown, because the data are a mixture of two binomial distributions, we can mathematically disaggregate the data and figure out what proportion of the population is engaging in the stigmatized behavior.
Like everything in real life, this is a TANSTAAFL problem. To get better answers, you have to sacrifice precision. That is, it costs more to get the same precision with randomized response than with direct questioning. My experience is that government survey outfits are unwilling to pay the price, they’d rather have high precision and low accuracy than slightly lower precision and much higher accuracy.
BC

By: serial catowner

serial catowner — Fri, 16 Jun 2006 15:17:52 +0000

Remove the source of funds for meth buyers? Uh, that would be American Suburbia, where everyone owns a car, houses are isolated and police are thinspread, there is a constant coming and going at all hours of the day and night, and mailboxes are made of tin.
And it’s not exactly a secret that recidivist drug users (other than pot smokers) are usually people with little education and less prospects of having a good job. Which leads to the strong suspicion that if you take away one intoxicant they’ll find another.

By: wren

wren — Fri, 16 Jun 2006 02:28:13 +0000

I don’t often scan all the articles on Slate but this morning I did. When I saw Shafer’s piece and I almost sent you (Mark) a heads-up so you could get your retort ready. Jeepers, you didn’t need me. You’ve got that much to say from just stream of consciousness? Impressive.
Of course, I agree with what you say about Shafer and King. Two quibbles – don’t call PSE sudafed. That’s Pfizer brand and BTW they have reformulated it w/o PSE. 2nd a success rate of less than 10% is usually not considered effective and that’s what you get with treatment programs. Even if treatment did show a higher success rate, it is fiscally impossible for most jurisdictions with meth problems to undertake programs at the needed scale.
Pardon me Mark if you’ve heard this before but the only forward is to systematiclay attack the meth supply chain. That means cracking down on Chinese PSE mfgrs., breaking the nexus between illegal Mexican immigrants and meth imports, using tools like GPS trackers to complicate the relationship between dealers/cookers and users/clients and by removing the source of funds for most meth purchases (petty theft, grand theft auto, ID theft). Reduce supply from China and Mexico and the ability of addicts to pay for it.
No big drug busts in Modesto, no lab seizures in Paw Paw, no miracle cures from Hythiam, just plain old economics.
BTW why does Shafer say what he says? Just to be contrarian? What a wanker.

By: Robert Waldmann

Robert Waldmann — Fri, 16 Jun 2006 01:52:59 +0000

“(Alcohol, of course, swamps them all.) ”
So does nicotine. Cigarette smoking is in decline and is now just the number 1 cause of avoidable death in the USA. And believe me it is “strongly reinforcing” that is highly addictive(he types as he chews his nicorette).

By: Kwix

Kwix — Thu, 15 Jun 2006 18:12:25 +0000

I am curious. If the NS-DUH, MTF and ADAM are not valid studies in Mr. Kleiman’s opinion; which ones should Mr. King have used? It is well known that all three studies are highly flawed, a fact that Mr. King acknowleges in his report by referencing none other than Mr. Kleiman (p.12). The reality is that any report on illicit and illegal drug activity (NS-DUH, MTF, ADAM, DAWN, YRBS, Harvard CAS, etc.)is likely to either under-estimate or over-extrapolate the numbers because actual hard numbers are impossible to obtain and verify.

By: serial catowner

serial catowner — Thu, 15 Jun 2006 16:54:03 +0000

I would be more inclined to use the term ‘epidemic’ for a situation in which a disease, probably contagious, spreads rapidly through a population until, perhaps, it becomes ‘pandemic’. In my life I’ve seen a lot of problems described as ‘epidemics’ that in fact appeared to be in some way self-limiting.
My general impression is that if society is working reasonably well, most people will not have a drug problem. Our society seems to resemble a man who inherited money and decided to buy a power tool for every task he faces. Deciding which part is working well, and which part isn’t, can get pretty complex.
Until we come to drug prohibition. With so many people in jail, and so many people using, we can see it’s not working.
But Wait!- There’s More!- Doctors afraid to prescribe analgesics, patients self-medicating, drug companies pushing the latest artificial analgesic, the supporting cast of drug task forces and poseur politicians- and, of course, a vigorous black market that could easily turn to smuggling something we would like even less than cocaine.
So maybe, for our own peace of mind, we need to focus on the details, and not see what’s happening to us. I’m just not so sure that will help anything.

By: JTS

JTS — Thu, 15 Jun 2006 16:45:53 +0000

Very nice post here, I’ll be quoting and linking over at my blog. I just wanted to hit again at one of the points you touch on, and that is the relative lack of epidemiological data on not only the extent of the problem, but the effects of the drug over time and over a large population. For some reason the gov. and groups like Partnership for a Drug Free America have no problem spending money on campaigns against drugs (which I’m not arguing against), but aren’t thrilled at the prospect of actually spending money on research to better arm ourselves against the problem.

By: Brett Bellmore

Brett Bellmore — Thu, 15 Jun 2006 16:34:18 +0000

“So it’s possible that the meth wave is less a problem we ought to be trying to fix than a situation we need to ty to adjust to as best we can.”
If cracking down on a bad drug can cause people to switch to a worse one, (Which is something we’ve seen over and over during this “war”.) maybe easing up on a bad drug can cause people to switch away from a worse one.
I wonder how bad drugs would be, if they were designed by the drug companies to minimize the side effects, rather than being designed by garage chemists to minimize the use of whatever precursor the government has decided to make hard to obtain?

By: No Nym

No Nym — Thu, 15 Jun 2006 15:45:40 +0000

My state has behind the counter sudafed, and front shelf mixes of pseudoephedrine and antihistamines. I had to laugh. How long before the home labs are using simple chromatography to bypass even this measure?

By: Anderson

Anderson — Thu, 15 Jun 2006 15:29:32 +0000

Allow me to guess that if Shafer were not, like me, annoyed at having to buy sudafed behind the counter, he wouldn’t be giving a rat’s ass about whether the meth epidemic were a myth or not.

By: daksya

daksya — Thu, 15 Jun 2006 10:57:18 +0000

One more thing -
“it’s more than a mythical problem.”
I never got the impression that Shafer denied that meth is a problem. Instead, his gist seems to be that no *new* epidemic has sprung up in the past couple of years. If current prevalence of meth qualifies as an epidemic, then this epidemic has existed for atleast 10-15 years now. In that light, it is disingenuous for Newsweek, and MSM in general, to wake up one fine day in 2003/4/5 and shout wolf, when that wolf has been hanging around for atleast a decade. I suppose Shafer thinks that ‘epidemic’ is too strong a characterization because MSM hasn’t termed it as such before the last couple of years.

By: daksya

daksya — Thu, 15 Jun 2006 10:26:45 +0000

“NS-DUH is a survey of the household population; it excludes those in prisons, jails, residential treatment facilities, and dormitories, as well as the homeless.”
Actually, it covers dormitories and probably many of the homeless.
——
The civilian, noninstitutionalized population of the United States aged 12 and older, including residents of noninstitutional group quarters such as college dormitories, group homes, shelters, rooming houses, and civilians dwelling on military installations.
——
“It’s possible to estimate the number of regular crack users from other sources; the right number is something like 2 million, not 600,000.”
Which sources are these? (Do you know when the results of the Virginia river cocaine study are due?)