This is your sampling on drugs
From Stuff, this morning
This year, and for the first time in New Zealand, Fairfax Media is partnering with the Global Drug Survey to help create the largest and most up-to-date snapshot of our drug and alcohol use, and to see how we compare to the rest of the world.
That all sounds good. The next line (with a link) is
Take the survey here.
That doesn’t sound so good.
This research group has been running a survey in partnership with UK clubbing magazine Mixmag for years, and last year branched out to ‘Global’ status with the help of the Guardian. Not all that global, though: more than half the respondents were from the UK, with half of the rest from the US. As you might expect, the respondents were more likely to be from demographic groups with high drug use: overrepresented attributes included young, male, student, and gay or bi. The research team and their expert advisory committee includes experts in a wide range of areas needed to design and interpret a study of this sort, with one exception: they don’t seem to have a statistician.
What are the results going to be useful for? Clearly, any estimates of prevalence of drug use will be pretty much useless if the survey oversamples drug users as it has in the past. Comparisons with past surveys done by different methods will be completely useless. International comparisons within the survey will be a bit dodgy, since the newspapers taking part will reach different segments of each country– readers of the Fairfax media are quite a different subpopulation than Guardian readers.
Useful information is more likely to be obtained on drug prices, on subjective experience of drug taking, on harm people experience from different drugs, and on comparison between drugs: eg, among people who’ve tried both MDMA and cocaine, which do they keep using and why? In countries where there is no high-quality survey information, the semi-quantitative information about drug use might be helpful, but that’s probably not true for NZ or the USA. Certainly for alcohol use, the NZ Health Survey would be more reliable, and the estimates of street price of drugs from Massey’s IDMS should be pretty good.
For New Zealand, the most useful outcome would be if the survey provokes a repeat of the NZ Alcohol and Drug Use Survey, which was run in 2007-2008.
[Update: the NZ Health Survey was planned to have a drug use module in 2012. I can’t find any confirmation that it actually happened, or any planned release date for the data. See the comments. The module was administered and data will appear next year. So, it’s definitely not true that there hasn’t been an NZ survey since 2007/8, contrary to the story]
Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient See all posts by Thomas Lumley »
The last I understood (and I could well be wrong) was that the NZ Health Survey, via the MoH, was in continuous sampling mode and that alcohol and drug modules and other modules were going in on rotation.
The only trouble is that it takes such a long time to clean and anonymise the data – it’s not so bad for older people and cardio-vascular health – that evolves slowly but drug and alcohol use changes relatively rapidly as young adults move in and out of their peak drinking years.
11 years ago
Yes, it does look as though the drug use module was supposed to be delivered in 2012, and it seems this was actually done
I shouldn’t have assumed the paper was accurate when it said the last survey was carried out in 2007-8.
11 years ago
Yup. See here for the trends:
http://offsettingbehaviour.blogspot.co.nz/2013/06/data.html
11 years ago
Eric, that’s the alcohol data. I knew about that and it’s actually linked in my post (and I’ve written about it before).
There was supposed to be a drug use module in 2012 (and then rotating every so often). I haven’t seen any data from that.
11 years ago
Ah, doh.
11 years ago
Hi. I am the manager of the NZ Health Survey. Great to seee the interest in the survey. Megan is right about the survey. Since 2011 the NZHS have been a continuous one with core questions that are asked every year and then a tiopic module that changes each year. In 2012/13 the module topic was Tobacco, Drugs and Alcohol. We are currently analysising this data and we will be reporting it within the first 6 months of next year. Cheers Marie
11 years ago
Great to hear!
Thanks for letting us know.
11 years ago
Hi. Pleased to see the conversation. Just to reassure people – this year we went ‘global’ translated into 8 languages and got 78,800 responses. Totally accept limitations of methods and sampling bias. Promise we work with clever stats people. And we only ever consider ourselves as a complementary data source and we do compare to local sources. NZ did a fab job – we got 5700 responses. Findings out in Stuff in April. Happy holidays all
11 years ago
Yes, I felt more positive about the survey after actually taking it — quite a bit of it is stuff that is usefully even if it’s only semi-quantitative.
11 years ago