The day
after the terrorist attacks in Paris, the Belgian policy held a nation-wide
campaign of speed controls. The campaign had been planned and announced well in
advance, but was not cancelled following the attacks.
This led
some moral outrage that was forcefully aired on the social media: “we are under
attack and the Belgian police is checking whether we are complying with speed
limits, where are these guys’ priorities?”
Well, the
answer is less obvious and thus much more interesting than the author of these
considerations may think.
Let us, for
a start, assume that this person was not simply self-serving in his moral
outrage, and is a law-abiding citizen who always complies with speed limits and
who is genuinely worried about our safety.
Is he right
that the Belgian police should have cancelled the planned speed controls?
The
behavioural economist in me cries:
“The reality is that, annually, 1.2 million people
are killed in road traffic accidents worldwide, an average death rate of 17.3
per 100,000 population. http://healthintelligence.drupalgardens.com/content/road-traffic-death-rates-across-countries-world-2013
On the other hand, less than 33 000 people died from terrorist attacks in 2014 http://www.statista.com/statistics/202871/number-of-fatalities-by-terrorist-attacks-worldwide/
. Thus, this cry of outrage on the social media is a typical example of the
so-called availability bias: the number of victims of road traffics may be
around 360 times larger than the number of victims of terrorist attacks, but
when people die from terrorist attacks, a lot of people die at the same time,
so we have the impression that terrorism is a much larger threat than road
traffic (especially when it happens in the city where we got engaged)”.
A smug
smile runs across my face and I think: “mission accomplished, another beautiful
example of deviation from rational thinking identified in the real world.”
Oh, but
wait a second: who says that police resources should be allocated on the basis
of the numbers of victims? A serious economic analysis also requires us to
calculate how many deaths (from road accidents or terrorism) can be prevented
by a given investment in police resources.
And this is
where we run into trouble.
For traffic
death prevention, the analysis is (in principle, if not in practice) quite
simple: we “simply” need to know how much value the “speeder” attaches to
driving faster than the legal limit, and we know that he will be deterred from
speeding if the value of speeding is smaller than the expected value of a
ticket for speeding. And this expected value is simply the product of the fine
and the probability of getting caught, which is in turn a function of the
resources invested in enforcing speed limits. Well, I know there are some
details that still need to be developed (does the speeder’s assessment of the
detection probability correspond to the objective probability, for instance?),
but, in principle, all these issues can be dealt with if we invest the necessary
resources in serious empirical research.
But what
about terrorism prevention? Do we know how the probability of catching the
terrorists before the act is affected by our investment in intelligence and
police work? Well, I am not sure we even can. When security on planes increased, terrorists
started attacking trains. If we increase security measures on trains, they will
start attacking buses. If we increase security measures on buses, they will
start attacking supermarkets. In other words, the more we protect specific
targets, the more the terrorists will act at random – which is precisely what
they have done in Paris. And if we can prevent them from undertaking random
attacks in cities, they will move to random attacks in villages.
What is
even more annoying with this type of terrorists is that it is not even clear
what would deter them even if they were caught with certainty. After all, the
only way to stop them is to kill them, and that is precisely what they want.
And, because of the availability bias, it is not sure that the effect on public fear of a
failed attack is that much smaller than the effect of a successful
attack.
So what
does all this imply? Well, I am not so sure anymore. Maybe I should just take
this smug smile from my face and start some real hard thinking about the
subject. And, maybe, after all, this whole discussion isn’t worth having. After
all, this guy on the social media is obviously a self-serving asshole who wants
to drive any speed he wants without getting caught, and who is using the
terrorists as cheap excuse. Is anyone suggesting that I am suffering from “representativeness”
or “stereotyping” bias now?
