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 NZ Drug's Jackson Wood said they came from an unpublished comparative analysis of the National Alcohol Use Survey Data 1995, 2000, 2005 from SHORE; I'll have to ask SHORE for a copy as NZ Drug doesn't have one.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.