Pete Brown has run a series of posts this week and last that delve into stats being issued by various government agencies and health lobby groups in the UK. It is important work that Pete is doing as there is no stat worse than the unexamined stat. Today's post was called "More Hilarity with Statistics" which examined claims about the level of drinking in Scotland. I made a comment over there but did some more rooting around to make sure I agreed with what I was seeing and, to avoid looking like a totally rude idiot being all finger pointy in the comments, thought I would set it out here instead. I also got thinking because even if a stat can be discredited it does not mean that the underlying facts necessarily do not exists, only that they are not well described. But, as I said in the comments, I am really bad at math so I am happy to be corrected.
The BBC story Pete began with was titled "Scots 'Drink 46 Bottles of Vodka'" by which they mean per person per year on average. Pete suggested that this was not particularly well researched as tourism trade taking the booze away was not figured in - but then when I ran the numbers I saw this pattern:
- Scotland has about 8% of the UK population
- total UK booze sales in 2007 were worth over 41 billion pounds
- and therefore, Scotland's booze sales can be approximated at around 4 billion pounds.
I took the numbers from this soul suckingly slow .pdf source. I read them to meaning that if every penny of the 25 million pounds spent at distillery shops was non-Scots resident alcohol sales, removing it entirely from Scottish consumption, it only represents well under 1% of total Scottish sales? If that is the case, the variation is under a bottle of vodka a year. I said that even if I was off by a whole decimal point and the distillery sales represent 10% of sales isn't it still a little bit alarming that every Scots adult averages 41 or 42 bottles of vodka a year? By which I mean I had a gut feeling it was in fact pretty high. But is it?
A little more looking around further, found information stating that 30% of Scots adults say they do not drink - which means the drinking Scot averages 58 or so bottle a year working off the conservative 41 bottles a week stat. It is more like 65 a year if you go by the BBC's number of 46. I got the "did not drink" percentage from this pdf. So you have 30% of Scots not drinking, 35% drinking up to the average and 35% drinking over the average.
What does that mean? 58 bottles a year on average means 1.12 x 700 ml bottles a week at 40% that means 313 ml of pure alcohol a week. By comparison, a standard Canadian 12 oz 5% beer has 341 ml. Which means that average Scots drinker's booze consumption is the equivalent of 19 standard 5% Canadian beers a week. Sounds like a bit more than you might think is a good idea, week after week day after day. But not fatal. It's maybe what we expect the average healthy working Joe would drink in a week. Similarly, a US 22 oz bomber has 650 ml. At 8% that is 65 ml of pure alcohol. Which means that the Scot's drinker's booze consumption is the equivalent of 4.8 bombers of 8% US craft beer a week. Is that going to scare off a craft beer fan? Hardly.
But it is an average and that is what I think is the real concern. It means 35% of Scots drinkers adults drink more... because 65% drinkers there drink less including the 30% who abstain. I think those numbers are troubling. They may well be wrong so please do your own a arithmetic. But if they are not wrong - is there not a valid public health concern where 35% of your population is doing that level of drinking. I don't really care if you think there is no such thing as a public health concern from a libertarian point of view as that is not the point here. Nor does someone called "Alan Campbell McLeod" care if you think this is only a Scottish problem. I think we can all agree that there is a point beyond which alcohol is unhealthy. Is that point been identified by the BBC report?