Drug convictions

The Drug Foundation's State of the Nation 2018 report has some nice stats that aren't typically seen all in one place. Here are drug convictions. 6000 per year in a country of 5 million seems high.

Demand for intoxication

A new survey finds teens in more deprived parts of New Zealand drink more heavily when they do drink, but do not drink more often than their richer counterparts.

While there's a general alcohol-income puzzle in that drinkers earn more than non-drinkers, a relationship generally hypothesized to be due to socialization and human capital building, demand for intoxication should be higher if your circumstances are worse.

The Herald cites a public health worker saying poverty fuels demand for this kind of intoxication, and hoping that local bodies will reduce the number of liquor outlets. I'm pretty sure, though, that Say's Law is meant to work for aggregate demand in the long run rather than for individual stores; closing liquor outlets will increase the cost of getting one type of intoxicating substance, but if the underlying demand for intoxication is still there, it would be surprising if there weren't substitution.

One bit from the Herald story bothered me though:

Statistics show binge drinking among Kiwi teenagers is increasing. Figures published by the New Zealand Drug Foundation show that between 1995 and 2004, the proportion of young people drinking more than six drinks on a typical occasion increased from 14 to 25 per cent in 14-15 year olds, 25 to 36 per cent in 16-17 year olds and 31 to 40 per cent in 18-19 year olds.

I had a chat with the New Zealand Drug Foundation about these stats as I couldn't find them anywhere. The Drug Foundation noted the stats in their Background Paper (pdf) on alcohol law reform (html version), but they don't provide the source of the statistics. NZ Drug's Jackson Wood said they came from an unpublished comparative analysis of the National Alcohol Use Survey Data 1995, 2000, 2005 from SHORE; I'll have to ask SHORE for a copy as NZ Drug doesn't have one. And the numbers do not match what I've seen in two other surveys.

ALAC reports seem to find no increase in heavy youth drinking from 1998 to 2009. I'd written previously:

In 1998, before the purchase age change, about 25% of youths aged 14-18 were non-drinkers. That dropped to 14% shortly after the law change (2000).

But, if we look at more recent figures we find (Table 18) that 88% of 12-14 year olds are non-drinkers, 46% of 15-17 year olds are non-drinkers, and 11% of those aged 18-24 are non-drinkers.

Unfortunately, the age groupings make those a bit hard to compare. But look at those numbers and judge for yourself whether it seems plausible that we've had big increases in youth (age <18) access to alcohol since legalization.

The same pair of reports have 31% of youths 14-18 drinking heavily in 1998 (reported 5+ drinks at last occasion) and 30% of those aged 12-24 binge drinking now (4% of those 12-14, 27% of those 15-17, and 44% of those 18-24). Again, youth binge drinking is a problem. But it's harder to say that it's a problem that's worse now than it was prior to the change in the purchase age; the proportions seem pretty similar.

The New Zealand Alcohol and Drug Use Survey's 2007-2008 report had a few interesting tidbits as well. Among 16-17 year olds who had consumed alcohol in the past year, the prevalence of hazardous drinking (not the same thing as binge drinking - binge drinking is one component of hazardous drinking) dropped from 38.5% in 1996/1997 to 26.9% in 2002/2003 before rising slightly to 30.4% in 2006/2007. The report noted, and I quote:

Hazardous drinking among youth

There was no significant change in the prevalence of hazardous drinking among past-year drinkers aged 16–17 years from 1996/97 to 2006/07 (Figure A15).

Among the total population aged 16–17 years, there have also been no significant changes in the prevalence of hazardous drinking since 1996/97 (Figure A16).

There was no significant change in the prevalence of hazardous drinking among past-year drinkers aged 18–24 years from 1996/07 to 2006/07 (Figure A17).

Among the total population aged 18–24 years there have also been no significant changes in the prevalence of hazardous drinking since 1996/97 (Figure A18).

So we have one unpublished report that perhaps is available on request noting an increasing trend in youth binge drinking through 2005, a pair of available ALAC reports that, between them, show no increasing trend from 1998-2009, and a Ministry of Health paper on the NZ Alcohol and Drug Use Survey showing no significant change but what still is a decline in hazardous drinking from 1996/97 to 2006/07.

I'm not posting this to pull the Drug Foundation's beard. I'm not sure if the bits I'm citing were available when they prepared their submission. And time pressures can explain a lot; if you have SHORE's survey data on hand at the time, looking around for other sources can have high opportunity costs.

But I hope that they're able to get some of the stats updated on their website. It makes me sad when the Herald cites them in support of numbers that may not be the soundest ones available, or that at least seem contradicted by two other more recent and publicly available sources.

Always extend the data series

The New Zealand Drug Foundation's submission on alcohol reform legislation included this factoid on total alcohol consumption.

Myth: Alcohol consumption has remained the same despite liberalisation of our liquor laws.

Fact: Total alcohol consumption has increased over the past decade. Total alcohol available for consumption (calculated from production, imports and exports) increased by 9.4% between 1998 and 2009 according to official data from Statistics New Zealand. This increase coincided with some of the most significant changes relaxing our liquor laws (e.g. purchase age lowered to 18, supermarkets allowed to sell beer and wine, Sunday trading allowed, starting time for alcohol advertisements on TV brought forward to 8:30pm from 9:00pm. Regardless of per capita consumption, it is how we are drinking that is even more important. There is clear evidence over the last decade that binge drinking is increasing.

That's at page 4 of their submission dated 18 February 2011. I was a bit busy at the time so didn't get a chance to fact-check it properly then. I'd pointed to some stats from David Farrar, but I hadn't checked them independently. I reckoned that likely worth doing now.

I can't link directly to the Stats NZ series; InfoShare is horrible on this one. You get a session link that expires and no permalink to the data series. Go to their search function, type "alcohol", and select the series "Litres of Alcohol Per Head of Population (Annual - Sep)" - that's the most recently updated one.

The first thing you'll notice is that, when you choose years, you can go back to 1986. So you should wonder why they chose 1998 as starting point. There was some liberalisation in 1999, but even then you'd want some sense of whether the prior trend were increasing or decreasing to get a handle on whether there could have been a regulatory structural break in the data.

If you look at alcohol per capita, you get about a 4% increase from 1998 to 2009. If you look instead at total alcohol without adjusting for population, you get a 25% increase; I'm not quite sure where 9.4% comes from.

At page 44, NZ Drug helpfully provides a timeline for us; I'll here crib their summary verbatim:

• 1989: Liquor licensing liberalised: previously based on community "need", now and "suitable" applicant with planning consent gets a licence (number of licences doubles in early 1990s), 24-hour opening allowed, supermarkets can sell wine.
• 1992: Alcohol brand advertising allowed on TV after 9PM, liquor advertising code transfers from Broadcast Standards Authority (Crown Agency) to Advertising Standards Authority (Industry Body).
• 1995: From around 1995 cafes start applying for licences; alcopops enter market.
• 1999: Sale of Liquor Act amended. Minimum purchase age lowered from 20 to 18, supermarkets allowed to sell beer as well as wine (but not spirits), seven-day trading for "taverns" and off-licences.
• 2003: Advertising Standards Authority (ASA) moves start time for television alcohol advertising from 9:00 PM to 8:30 PM.

If liberalisation is what causes big increases in consumption, we'd expect that the trend that NZ Drug cites from 1998 onwards is the continuation of a big increase in consumption. [Update: Jackson really helpfully points to NZ Drug Foundation's direct-link timeline.

Here's what we get when we extend the data series.

There was a substantial drop from 1986 through 1997, from over 12 litres per person aged 18+ to just under 9 litres. Since then, it's come back up to around 10 litres, with a bit of bouncing around that value. By 1989's reforms, alcohol available for consumption had dropped to about 90% of its 1986 value. It dropped by 1997 to 73% of the 1986 value. And we're now at about 80% of the 1986 value.

So the NZ Drug Foundation is entirely right that there was an increase since 1998 and that there has been liberalisation since 1998. But 1998 was awfully close to the series minimum, the period prior to 1998 experienced strong decreases in total per capita alcohol available for consumption, and it's debatable whether the 1989 or 1999 changes were the greater liberalisation.

I don't mean to pick too much on the Drug Foundation here; I've seen all kinds of folks pointing to the increase in consumption over the last decade without noting the much larger drop over the prior decade. And, they're being kind enough to print my summary of the lit on the J-Curve. NZ Drug was just the first place I could find it when writing up the post.

As for binge drinking, I've pointed before to MSD's Social Report on potentially hazardous drinking, which will combine binge drinking with overall heavy drinking:

There's a small increase in problem drinking among most age cohorts and a small decrease for one age cohort. I've never been able to see much evidence of a crisis in this graph. 

One lesson for journalists in New Zealand: whenever anybody gives you a New Zealand data series that has a start year that isn't 1986, go to Stats NZ and extend the data series. A whole pile of NZ data starts at 1986; if the data you've been given doesn't have a 1986 start point, you might want to check if there's any reason why.

You can't kill a bad stat

The New Zealand Drug Foundation should know better. And yet, here we are.

The NZDF put up a Bingo card for those who support tougher regulations around alcohol with the catch-phrases they expect to show up in the debates around the Alcohol Reform Bill. The last page of it has a few problems. Alcohol Reform Bill Bingo  Among the facts, as NZDF sees things:

It's a small number who are ruining it
Since when is 785,000 a small number? That's how many "uninhibited binge drinkers" there are in New Zealand. A further 622,000 people are "constrained binge drinkers". Together that's 1.3 million people, about a third of all drinkers in New Zealand who are not drinking responsibly.

nzdrug.org/smallnumber

Ok. First off, there are 4.4 million people in New Zealand. They're claiming 1.3 million is a third of all drinkers. So they're claiming that we have 3.9 million drinkers in the country. At the 2001 census, there were about 848,000 people aged under 15. So the New Zealand Drug Foundation is claiming that every single person aged over 15, along with 41% of all of those aged 0-14, are drinkers. That seems off.

So I hit their provided link. It's a redirect that goes to an article by Sally Casswell. That article provides results from a survey where they asked a representative sample of people a bunch of questions, including whether they know anybody who they consider to be a heavy drinker. 29% of the sample reported knowing at least one heavy drinker. Now it would be a really really big mistake to extrapolate from the number of heavy drinkers known by people in the sample to a population estimate of the number of heavy drinkers because respondents could easily be referring separately to the same heavy drinker. And, Casswell doesn't do that. In fact, there's absolutely nothing at the link to back up NZDF's claim here. I think this is likely a redirect error: the study backs up the number in the next factoid, where they say "about a third of New Zealanders have at least one heavy drinker in their lives" (note that 29% is almost equidistant from a quarter and a third for rounding purposes. Since a third is 33.333% and a quarter is 25%, a third is just a pinch worse for rounding purposes than a quarter, if you want to be accurate and you like fractions. But you always round up if you want the scarier fraction).

But, because I work in this literature, I know where their number comes from. It's from an old ALAC report, cited here. What counts as an "uninhibited binge drinker"? It's awfully hard to tell from the report. They define it as:

"adults, 18+, who are less concerned with the effects of their drinking and less inhibited than Constrained Binge Drinkers. They drink regularly (often every day) and binge, mainly to unwind, and for the "buzz" and enjoyment."

By my best guess, adults who drink regularly, who sometimes binge, count as "uninhibited" if they don't seem sufficiently contrite about it in the survey questions. At page 25, they say that the main difference between constrained and unconstrained bingers are "demographic and attitudinal characteristics", with the unconstrained exhibiting a more reckless disregard for downside costs of heavy drinking. What counts as binge drinking?

"where an adult reports they have consumed the equivalent of seven (7) or more glasses of alcohol during a single drinking session."

I'll assume that they're there meaning standard drinks. Seven standard drinks, 70 grams of alcohol, is the equivalent of most of a bottle of standard strength wine (a bottle usually has 8-9 standard drinks). A half-litre of Emerson's JP is 3.27 standard drinks. So less than two pints of the JP makes you a binge drinker. Since I have about 0.6-1.3 standard drinks per typical day and perhaps once every month or two have something more like a couple pints of JP (over 3+ hours), and because I really can't see any negative consequences from my drinking pattern, I might count as an uninhibited binge drinker - it depends how often you have to binge to fall into the category. Figure 4 of that report shows that 56% of "uninhibited binge drinkers" had 3 or fewer drinks on their last drinking occasion; 25% of that category consumed 7 or more drinks on their last drinking occasion. So it's not implausible that a lot of people fall into the category. But does the category really tell us a ton about anything useful?

At page 75, the ALAC report compares uninhibited binge drinkers who drink every two to three days and who drank 7+ drinks on the last occasion with those who don't. The heavier drinking members of the uninhibited drinking cohort are more likely to be full time salary or wage earners, have higher income, and are more likely to drink with friends than to drink alone. Are any of those bad things?

But, the worst stat in NZ Drug's "Facts"? This one.

The status quo is fine.
The status quo means 1000 deaths due to alcohol every year. It means 785,000 binge drinkers. It means $72,000,000 in costs for Police, Corrections and health expenditure. It means $4.8 billion in costs to the taxpayer. The status quo means more harm.

nzdrug.org/alcoholreform

I don't know about the 1000 deaths; I hope that it's net of the lives saved by moderate drinking, but I doubt it. The 785,000 binge drinking figure seems a bit off, as noted above. The $72m figure is included in the $4.8 billion figure. And, the $4.8 billion is not a cost to the taxpayer. Again, here's BERL's cost tally:

• $1.52 billion in intangible costs of loss of life (the vast majority of which is reduced life expectancy among very heavy drinkers, with no accounting for increased life expectancy for moderate drinkers);
• $1.48 billion in labour costs of lost productivity (the vast majority of which are the forgone production of the prematurely deceased, and consequently is double-counted with the $1.52 billion above since the Value of a Statistical Life is inclusive of lost production);
• $699 million in "drug production costs", including every cent of excise paid to the government by heavy drinkers;
• $562 million in crime costs, with a ridiculously low threshold for determining what is an "alcohol-caused crime";
• $290 million in health care costs, under the assumption that there are no health benefits from moderate drinking and by zeroing-out the effects of drinking for those disorders where even fairly heavy alcohol consumption reduces the costs of that disorder;
• $200 million in road crash costs, consisting both of those very real costs that drink drivers impose on others and the costs that drink drivers impose on themselves by wrecking their cars;
• $42 million in lost quality of life, again mostly falling on heavy drinkers themselves.

When I'd gone through the figures it looked like maybe $967 million of BERL's $4.8 billion could count as an external cost by more normal method.

It's hard to kill a bad stat. Darned things keep popping up whenever somebody finds them to be convenient. 

Welfare reform and drug use

The New Zealand Drug Foundation wrings its hands about potential changes to New Zealand's welfare rules:

The Drug Foundation says punitive measures being considered against drug users who are on benefits could exacerbate poverty, increase crime and harden substance dependency.

It is so concerned about the Welfare Working Group's "flawed populist assumptions" about substance abuse that it is urging the Government to work with mental health and addiction specialists when considering its recommendations.

The group wants strong rules and obligations for drug and alcohol use by beneficiaries, enforced by a graduated sanctions regime.

Drug and alcohol-dependent beneficiaries would be offered free treatment services and those who failed drug or alcohol tests would face cuts to their benefits and a 13-week stand-down for the third offence.

Hope Corman visited Canterbury's economics department a couple of years ago. She found pretty strong evidence that American welfare reform, which included sanctions for drug use, strongly reduced drug use. Here's her NBER working paper:

Exploiting changes in welfare policy across states and over time and comparing relevant population subgroups within an econometric difference-in-differences framework, we estimate the causal effects of welfare reform on adult women’s illicit drug use from 1992 to 2002, the period during which welfare reform unfolded in the U.S. The analyses are based on all available and appropriate national datasets, each offering unique strengths and measuring a different drug-related outcome. We investigate self-reported illicit drug use (from the National Surveys on Drug Use and Health), drug-related prison admissions (from the National Corrections Reporting Program), drug-related arrests (from the Uniform Crime Reports), drug-related treatment admissions (from the Treatment Episode Data Set), and drug-related emergency room episodes (from the Drug Abuse Warning Network). We find robust and compelling evidence that welfare reform led to declines in illicit drug use and increases in drug treatment among women at risk for relying on welfare, and some evidence that the effects operate, at least in part, through both TANF drug sanctions and work incentives.

The paper was also written up in the Wall Street Journal.

So I really hope that the government takes the Drug Foundation's recommendation and consults with specialists. In particular, they should fly Hope Corman back to New Zealand. It would be great to see her again.

An anti-drinking campaign I can endorse

We know that the risk of death is lower for moderate drinkers. Folks consuming about a drink per day have only 85% of the mortality risk of non-drinkers, correcting for all the confounds.

The New Zealand Drug Foundation is encouraging politicians to sign up for its FebFast fundraiser, where folks pledge funds and commit not to drink for a month. The money goes to charity. The increased mortality risk goes to politicians, though those who otherwise were drinking more than 4-5 drinks per day would see a net reduction in mortality risk. Sounds like a pretty good deal.

Since the real lushes in Parliament are least likely to sign up for this kind of thing, it's an initiative that I can endorse. In fact, there are a few that I'd even consider helping to sponsor. Please take it as a complement if I turn you down if you ask me for sponsorship: it's for your health. I can't think of more than a couple of MPs that I'd refuse. I'd also refuse Winston, but only because I think he might pocket the money, renege on the deal, then threaten defamation suits against any media outlets showing pictures of him having a drink during February.

*Please do not take this as my being serious about wishing harm or increased risk of all-source mortality on any politicians in New Zealand or elsewhere, especially if such thoughts could be held against me.

Moderate drinking and health

My best read of the evidence is that moderate drinking reduces mortality risk. Most work finds a J-curve relationship: the relative mortality risk of drinking decreases for light to moderate drinking, becomes comparable to teetotalling somewhere around 30-40 grams of alcohol per day, then continues increasing. The curve looks a bit like the letter J, though it never gets quite as vertical as the letter.

There are, of course, lots of studies out there, of varying quality, and they don't always agree.

And, worse, there are some nasty potential confounds out there. One obvious one, which folks dismissive of the J-curve relationship tend to promote, is that many studies confound never-drinkers with ex-drinkers. If someone quits drinking because he's destroyed his liver, it would be a mistake to class him as a non-drinker to evaluate the health effects of moderate drinking. Other potential confounds include omitted variable bias: if moderate drinkers also tend to have better health behaviours than heavy drinkers or non-drinkers, then the relationship could be due to the other health behaviours rather than due to the alcohol.

The best way forward is a decent meta-study that pools results from various studies and assigns them weight according to how well the study was conducted, or takes averages across different sets of studies that control differently for various effects.

The best one of these I've seen is Castelnuovo and Donati's 2006 paper from Archives of Internal Medicine. They strongly endorse the J-curve relationship. They pool 34 studies of a total of more than a million individuals. Some of these studies include former drinkers with abstainers; others carefully separate them out. But both types of studies find a J-curve. Including former drinkers as never drinkers biases things, but not enough to overturn the result: the studies that are more careful still show a strong J-curve relationship, just with the curve cutting the x-axis around 30 grams per day rather than around 60 grams per day.

Castelnuovo and Donati note the problem of omitted variable bias, but suggest it's likely to be pretty limited. They note that the health behaviour covariates included in those studies adjusting for those covariates only have small effect on the overall curve: the unadjusted figures show a maximum risk reduction of 19% while the adjusted figures knock that back to 16%. There will of course be other health behaviours correlated both with drinking and with mortality outcomes, but they would have to have more than five times the effect of the observable health covariates to flatten the J-curve to a hockey stick. That's rather implausible. Note of course I mean a proper hockey stick held with the shaft horizontal - not one of those silly Kiwi lawn game sticks.

In the economics of discrimination literature, we can pretty readily believe that the 5% or so remaining difference between blacks and whites in wage regressions is largely due to unobserved variables that correlate both with wages and with race. If observable characteristics correlated with race and wages knock back the wage gap from 20% to 5%, then it's pretty plausible that unobservables might have a quarter the effect of the observables. But having five times the effect of the observables? Nah.

And so I was pretty surprised to find that the New Zealand Drug Foundation considers the J-curve a "myth". Why do they think it's a myth? Non-randomised trials suffer from omitted variable bias and often conflate never-drinkers with former drinkers (egads, asked and answered!). What do they cite?

• Chikritzhs et al 2009, the upshot of which seems to be "oh, empirical work based on surveys is hard, so we really can't say anything that might encourage people to drink". For what it's worth, Chikritzhs also spends a fair bit of time investigating the evils of the alcohol industry and pushing for new and higher alcohol taxes;
• Connor et al in the NZMJ. This is a fun one. They say alcohol's responsible for 1037 deaths but helps prevent 981 deaths, for a net loss of 56 lives in 2000. They also specifically tally more than 4000 life years gained due to reductions in ischaemic heart disease associated with alcohol consumption. Hardly a great source if you want to claim that there's no benefits of moderate alcohol consumption! I wish they'd listed which claims they wished to back up with Connor et al's piece. Connor specifically says that there are health benefits from regular moderate drinking for those middle-aged and older;
• Mukami et al on beliefs about moderate drinking
• Rimm and Mukami 2008, the upshot of which is that since moderate alcohol consumption increases some disease risks while decreasing others, we might want to be careful in recommending moderate consumption to folks with a very strong susceptibility to the disorders that alcohol exacerbates (we'd presumably then also want to more strongly recommend it to folks with susceptibility to disorders attenuated by moderate alcohol use);
• Doug Sellman (et al)'s 2009 "Viewpoint" piece in the NZMJ that alcohol cardioprotection has been talked up (never mind that Corrao 2000 definitely finds a J-curve in cardioprotection for both high and low quality studies, and that Rimm and Moats 2007 are trenchant about recent efforts to downplay the existence of the J-curve)

So they're relying on some op-eds and nebulous worries about the quality of existing studies rather than the best consensus estimate of the literature.

Of course, they're not the only ones. The WHO also spends a bit of time trying to talk down the cardioprotective effects of alcohol. I've noted before the WHO's ongoing war against alcohol, so it's little surprise they play a bit loose with the literature.

WHO briefly notes Corrao et al, blustering on about confounding where non-drinkers are lumped in with former drinkers, but Corrao specifically checks for that and finds that the J-curve on coronary heart disease doesn’t go away when you have studies that split out former and never drinkers. And, they get Corrao simply wrong on another dimension: they cite it as a meta-study of 28 cohort studies: Corrao based its main findings on 28 high quality studies but also presented findings from the 51 overall studies they’d selected: the selected studies showed a smaller J-curve effect than the 51, so they weren’t picking the 28 to get a larger J-curve.

It instead looks like WHO was trying to downplay Corrao relative to Fillmore, making it seem as though the gap in number of studies covered was much larger than in actuality. Corrao is listed as a meta-analysis of 28 while Fillmore is "a recent meta-analysis of 54". Fillmore disagrees with Corrao but Fillmore’s results seem to hinge on the two studies they view as being error-free; Corrao’s results just seem more robust. And, Rimm and Moats (2007, linked above) nicely show Fillmore’s results to be outside of the norm.

While WHO doesn’t bother noting Castelnuovo’s extensive meta-study on overall mortality it cites Jackson’s op-ed in the Lancet, almost every objection in which is answered in Castelnuovo. And, the WHO doesn't even note that their footnote here points to a two-page Lancet op-ed (it's in the "Comment" section) rather than to an empirical study. The WHO paper just isn’t good science. It's motivated reasoning.

The Drug Foundation thus far stands by its Mythbusting article. That's disappointing. If the goal is healthism, the best evidence suggests that a bit less a drink a day has the greatest mortality risk reduction, that there are still health benefits (relative to teetotalling) up to about three or four drinks per day, and that folks ought to be cautious about adverse health effects beyond that. They might also note that folks with family history of cancer drink a bit less while those with family history of heart disease drink a bit more. The economist would then say to weigh the health costs of drinking more than the health-maximizing amount against the consumption benefits.

I'm a bit puzzled why the anti-alcohol folks would want to bury the evidence of a J-curve - I have a very hard time seeing how a truth-seeker could find other than that there's a J-curve on the balance of the evidence. Is it the noble lie: that folks who've heard of the J-curve would use it to rationalize far greater drinking, so it's best to pretend it doesn't exist?