Tuesday, 4 January 2011

Yes, Virginia, epidemiology is really hard

I had been trying to get away from these road safety rants of mine, I really had.

But this was too interesting to pass up: An interesting, amusing (as in "funny hmmm....") and self-aggrandising article from the Courier Mail: Fast-aid cuts road toll to lowest since 1952 (January 04).

What does? I thought it was speed cameras! Also: Where, dear deity, did that hyphen come from? "Fast-aid" isn't mentioned elsewhere in the article so it's not a brand or other name, and clearly it's not a compound adjective - "cuts" is a verb. It's bloody stupid, is what it is.

The point of that article, as expressed concisely and almost well in the lead, is:

BETTER, faster ambulance crews helped Queensland achieve its lowest road toll last year since accurate records began in 1952.

Again: I thought it was speed cameras!

In the midst of a health system SNAFU (it's probably so long-term it doesn't deserve to be called a crisis anymore) where staff aren't paid and emergency beds have waiting lists, hearing that any aspect of the ambulance system has been improved is fantastic.

What interest me here, however, is that it is a beautiful, nay, elegant illustration of the fact that reality is really complicated and, therefore, epidemiology is quite hard.

There are two factors affecting the road toll: How many people are injured badly enough to be fatal and; how many are given adequate treatment. The first factor can be broken down into: How many people are involved in potentially fatal accidents and; how well they are protected by the car and fate.

The road toll is therefore affected by road and traffic conditions, the judgement of drivers, the road-holding and handling of their cars, the crash protection and passive and active safety features of those cars, and the response times and skill of all arms of the emergency response services.

This is why I keep describing the road-safety debate as puerile, shallow and all but a waste of time.

The point of this article is that: The road toll is lower because more people are being prevented from dying.

Yes, there are numerous other factors, short- and long-term. But I would really, really love to see the figures reported as: total accidents/potentially fatal accidents/fatal accidents. Give us some perspective.

There is also this:

In 2010, there were 5.5 road deaths per 100,000 Queenslanders, which met a target to virtually halve the rate from a decade ago.

Note halve. There are more many more people using the same road network, meaning higher traffic densities, meaning greater risk, and yet per capita roughly half as many people are dying. If you ever look at the annual traffic toll and observe the sameness of the figures from year to year, ponder what that means in terms of a growing population. It means that it has never been safer to be driving. Well, not since cars were limited to walking pace and they attracted gawkers wherever they went.

Well, they're using a historical low for comparison purposes, which will make any statistician beat their head against their desk, but you see the point.

Whether it's due to stick approaches like cameras, or better driver training (although I have my doubts) or the simple fact that cars are improving in capabilities and tank-like levels of occupant protection out of sight (and bikes get the occasional nice feature like ABS or traction control) while the roads and speed limits are staying the same, we have seen real death tolls plummet.

I'm not sure which is worse: The publicly portrayed understanding of causality or the public portrayed understanding of mathematics.

Monday, 3 January 2011

How road safety articles should be

After so much ranting and so many brickbats, I felt I should really present a bouquet.

This is now three weeks out of date because, well, that's what the past month's been like.

It was from the Queensland Times, by staff journalist Andrew Korner (who's also a nice bloke) and it's the first halfway lengthy newspaper/online article on road safety I've seen in quite some time that hasn't lowered my opinion of the outlet and/or the talent being quoted.

The title is a nicely positive Annual Ipswich road toll slashed.

The reason I like this is right up front in the first paragraph, and doesn't get worse:

POLICE have attributed a sharp drop in the number of Ipswich road deaths to drivers making smarter decisions and obeying the rules of the road.

Lower down, a direct quote from Snr Sgt Hamilton which may be the best yet on the topic at hand:

"At the end of the day a traffic crash is the result of people making poor choices and it's that fewer people have made poor choices on the road that has led to the reduction."

Slightly mangled syntax (pot, kettle, black...), but you should be able to detect that this is the most intelligent thing I've seen said about road safety in some considerable time.

He's not focusing on one problem which is a factor in less than a third of crashes, he's not talking down to motorists, he's recognising the complexity of the problem and the paradoxically simple solution: Drive smarter.

Can we get this guy as spokesman state-wide, please?

Lower down, after an out-of-place all-caps IPSWICH traffic branch's 21 officers... we are told that police will be patrolling roads, conducting RBT's and speeding, licence and vehicle checks. Speeding as one component of a complete approach - wow.

Finally, I was ecstatically glad to see something other than speeding identified as one of the most common contributing factors (note: contributing factor, not cause): fatigue. This particularly makes me happy because the fatigue-awareness ads we've had are, almost exclusively, better than any of the anti-speeding (not speed-awareness: anti-speeding) ads.

Particularly the ones with Dr Karl in them.

News reports don't have to be bald, basic, simplistic, or pandering to lowest common denominators. I maintain that even the most purely objective news media has a role to play in encouraging thought, debate, discussion and a general improvement in the logical and cognitive capacity of the community at large.

Plus, if you talk to adults on their level you're much more likely to enlist first their ears and then their support.

I really, really want to see more like this.

There is an art to good coffee and there should be

Nearly three years ago now I was pushed into rant mode by the then-new coffee machines using little prepackaged pods of coffee.

Nespresso machines are clean and neat and easy but generate huge amounts of excess waste packaging and take all the fun out of making coffee and the website is built using flash.

I've recently encountered one of these machines again and, I have to say, they can make a quite decent cup of coffee. But three years later, are the arguments stacking up any differently?

No. They're not.

Have a look, for example, at the next café you go to. Airport, McDonalds, pub, actual café, wherever. They're all still using the old-fashioned hand-operated machines. Not only do they not use prepackaged pods, they don't even use those fully-automatic fancy expensive machines that grind their own beans, measure, pack, tamp, espress, clean, all at the push of a button. No, they're all using the most time-intensive, skill-essential old style where a human has to do the measuring, tamping, and sometimes even timing of the draw. And then there's coffee grounds everywhere and it has to be constantly cleaned. This may be at least partly to do with image, but the benefits of a skilled barrista making coffee by hand can not be overstated.

And then there's the more concrete and psychological reasons.

Have a look at the price of the the pods. For a start, they're very difficult to get - they're not in supermarkets, for a start. An eBay search finds lots of 50 pods available for just under $50 including postage, or just less than $1 each. I haven't checked the prices on Nespresso's website because it requires you to register first, and frankly I'm not going to give them the satisfaction even in the name of journalistic investigation. Well, not unless someone pays me for it, anyway. Googling is immensely frustrating, so let's just say that $1 per cup is a good round number.

Now, I pay about $9 for a 200g tin of coffee, ground to my specification. A shot of espresso is technically 7g, according to my measuring spoon. That's about 28 shots of espresso per tin (which is frighteningly small, and explains why I have to get it refilled so often). That's 32c per cup. Even at those small prices, one third the cost adds up. Plus my tin is reusable, which means that my packaging cost is the bulk packaging that beans get delivered to my outlet in. My one reusable tin, or 28 little pods that take up a lot more space in the trash? My grounds don't even get thrown out - they end up as organic material in one garden or another.

But, finally, the one argument above all others I care about: Coffee is supposed to be involved. It is supposed to be a ritual. Coffee from a Nespresso machine may be nice, when you've picked the right pod, but it is the least satisfying cup you can possibly drink.

At home I have three different plungers, three sizes of stove-top machine (should be four, I need to replace my sadly departed one-shot machine), an espresso machine (that needs a new pump) and we even have two drip-filter machines, one larger and more complicated than the other and both of them living under the bench because, after using the timer feature about twice, my partner went back to using a plunger when she felt like real coffee.

And all of them have their individual little techniques and processes worked out over many years to produce just the right result. For example: For a pot on an electric element, the best procedure is to turn the element on first so it's hot when the pot goes on it, use filtered water from the fridge and take it off just as it starts to hiss towards the end of extraction. For a plunger, don't let it sit or it'll go bitter. Pour, plunge, pour (some people say stir, but you get that from pouring water in the right way). The espresso machine is, of course, an art in itself.

They are all of them satisfying. Making a cup of coffee, if you're going to move beyond instant, is a ritual. It has its rules and its regulations, its shibboleths and its superstitions. Its, to borrow a term from an excellent source, cultural chemistry.

That's without even going into the way I drink it - the single shot of espresso as a drink for pleasure, the standard-strength long black as a drink for productivity, the double-strength long black to get me over the finishing line when the brain starts to fade.

I really wouldn't have it any other way.

Everyone needs some luxury in their life and if you want to put your coffee effort into paying for pods and ordering them online and throwing out the detritus, go ahead. I'm going to put my effort into actual coffee.

Sunday, 2 January 2011

Do we make them justify anything?

In case you haven't worked this out already: I really, really don't think much of the road safety discussion currently being played out in the state and national media.

It's important but it's crude, simplistic, over-wrought and driven far too much by government and police sound bites, and I don't even mean the almost exclusive focus on deaths to the exclusion of permanent trauma causing lifelong disabilities at a tremendous emotional, physical and financial cost to individuals and their families.

And most of the discussion orbits the topic of speed cameras.

In order to justify the use of speed cameras as a road safety initiative, not merely a fundraising initiative, there needs to be a direct and confirmed causal link between the usage of cameras and an overall reduction in the rate and severity of accidents. Not just a correlation - a causal link. There are too many possible factors impacting driving behaviour for us to jump to a simplistic conclusion if there's a dip in the death rate.

Then, if we've done that, we need to be sure that there are more effective, more cost-effective ways of addressing the road toll. Maybe speed cameras work, but not as well as some of the alternatives.

Maybe the road and traffic authorities know what they're doing. But it's really hard to be sure of that, because they're not talking as if they do.

Let's start with More speed cameras deployed to cut road deaths from the ABC (December 15).

It tells us: Police are trying to cut road deaths; they are putting camera vans in 40 and 50 kilometre per hour zones; there are more camera vans in service (12, now); in two years 57 people have died in 40 and 50 zones; the road toll is lower than it was last year, and; putting camera vans in low-speed areas is part of a plan to cut the road toll.

There are logical holes in that. There is no justification that camera vans help to lower the road toll, they are concentrating resources on areas with a very low percentage of the toll (57 in two years, when the two-year total toll is in the region of 600) and where death is less likely due to the low speeds anyway.

Are non-suburban areas less important? Or is it harder to put resources there, so it's too much of an effort?

There is not even any indication of how many deaths are related to speed anyway, which would give the public some hope of working out for themselves if the tax money they're paying to be used in crude behaviour modification on them has any hope of being spent in a way remotely resembling good value.

From the Brisbane Times (December 18), we have Sixteen reasons for covert speed cameras.

Ooh! Justification!

Hahahahaha, psych! No, it's just another article saying "We have road deaths, let's do something simple and easy."

Here's the interesting part, right up front: 16 speed-related deaths in two years in 40 and 50km/h zones. That's 16 out of 57 in low-speed zones, or 28 per cent, or less than one third, and that's out of a tiny proportion of the total. Tell me: What are the police doing about the 72 per cent of deaths that weren't speed-related? Anything?

If we take a two-year total of about 600, that is, as pointed out in the comments to this article, about 2.7 per cent of deaths getting the added attention of two covert camera vans. May I suggest that's a little disproportionate?

There is, however, a balancing although inadequately explored opinion delivered by National Motorists Association of Australia, saying that covert cameras are all about revenue raising and can never be as effective as police on the streets.

It would be nice to have some sort of discussion about why that is.

Finally, appearing in the RSS feeds as "Speed cams are lifesavers" (what, muscular men in red speedos?), the Courier Mail gave us Covert speed cameras linked to Queensland plummeting road toll.

Okaaaay. Linked by whom? Statisticians? Accident researchers?

Well, I've read the entire article twice and I'm still not sure. It's not really stated.

The salient points are: A poll showed 25 per cent of motorists have changed their behaviour as a result of covert speed cameras; quite a lot of money has been charged in fines this year, and; there are concerns of a bounce in the accident rate as people adjust their expectations and return to previous behaviours.

The whole "cameras = less deaths" thing is only ever hinted at.

It is assumed that "changed their behaviour" means "safer." They might, instead, be driving slower but angrier and more aggressively. They may be safer but it could be because people are more alert on the roads trying to spot covert police and are therefore more aware of road and traffic conditions, rather than because they're driving slower.

If that's so, then good. But there might be better, more generally useful ways of getting the same result.

It's even assumed the current low death toll has any explanation beyond annual fluctuations. I've forgotten too much about statistics to know what the thresholds are and gee, it'd be nice to hear someone explaining it.

As an exercise, I went to PubMed, typed in "speed cameras" (with quotes, to get the actual phrase) and had a quick read through the abstracts of relevant articles.

There's the usual problem of identifying articles that have anything to do with the topic, and then when you find them there are a nice smattering of methodological problems. I even found one article finding a difference in effectiveness between different types of roads, and then another article using one category of road as a control and the other as an intervention group.

There was also, astonishingly, a Cochrane review, conducted by researchers right here in Brisbane.

Going to the source, we find that the Cochrane Library contains 12 articles relating to prevention of traffic crashes.

(NB: The conclusion of Motorcycle rider training for the prevention of road traffic crashes is "We have no idea, no study has been of a high enough quality to justify drawing any worthwhile conclusion.")

The camera review is here.

A review of 35 relevant studies concluded that cameras are associated with lower speeds and lower rates of accidents, but the degree of effectiveness can't be confirmed because the studies are of varying and generally moderate quality.

There, see? We have a result: Research has concluded that speed cameras help lower the road toll. It took me five minutes to find that.

Now, before I have any faith that my tax dollars are being well spent, I want to see:

  • Discussion on the best form of cameras - point-to-point, visible fixed, visible temporary, covert temporary, and visible or covert vehicles in the traffic flow.
  • Discussion on what to do about all the accidents that aren't related to speed.
  • Some sort of visible commitment to research-based policy.
  • Research into why cameras have that effect, and how to maximise it.

I know, "tell him he's dreaming'."

We can hope.

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