Saturday, August 25, 2012

Dan on crime - a lesson in the abuse of statistics

Dan O'Brien, writing in the Irish Times on Friday, claims that poverty and inequality are "not key reasons for law breaking" and that "recessions have had no discernible effect [on crime rates]". I call bullshit, and here's why (written as a direct reply to Dan's article, this is an edited version of the comment I left on the Irish Times site).


"Aw, people can come up with statistics to prove anything Kent. Forty percent of all people know that."
            - Homer J. Simpson


Wow, this is a breathtakingly ill-informed piece of lazy journalism, and an outrageous abuse of statistics!

The commenters on the site have already pointed out some of the flaws in your argument, but there are other ways in which this is simply wrong.

For anyone interested in a serious discussion of incarceration, I would highly recommend David Cole's article from the New York Review of Books from a few years back (and which I previously blogged about here).

According to Cole, “most of those imprisoned are poor and uneducated, disproportionately drawn from the margins of society” (referring to the US prison population).

The US has by far the highest incarceration rate in the world. However, somewhat inconveniently for your argument, Cole also points out that up to 1975 the US incarceration rate had been steady at about 100 per 100,000. Since then, the rate has ballooned to 700 per 100,000. If putting the crooks behind bars is really what prevents crime, it seems strange that such a massive increase in the incarceration rate apparently had no preventative effect on the 'crime waves' of the 1980s, to which you also make reference.

Incidentally, it is also slightly inconvenient for your argument that Russia, a country that you refer to as having “a very high murder rate”, also has the second highest incarceration rate in world. Huh.

But of course all of these superficial correlations are meaningless anyway (as you point out yourself!). What you are doing is taking two trends that happen to be moving in the same direction (or in some cases opposite directions), and assigning causation, in blatant disregard of your own caveat about correlation not necessarily implying causation!

Your country comparisons are also spurious. You simply can't compare crime rates and income levels across countries without at least attempting to control for some other relevant factors. Any applied economist worth their salt would know this. Two such relevant factors, which you mention in your article, are the rate of drug use (or perhaps more importantly narcotics production) and demographics. Controlling for these might lead to a very different picture of the relationship between income and crime (or it may not, the point is we simply don't know, based on the evidence you present). In any case, it seems likely that relative poverty and relative deprivation (i.e. within countries) would be more important drivers of crime than aggregate national income levels.

It is astonishing that you would make such sweeping assertions about what does or does not cause crime on the basis of so little evidence, and that the Irish Times would publish this piece seemingly without having done even the most basic fact-checking. (On that point, it is worth referring to Paul Krugman's recent article in which he outlines the fact-checking process that each of his op-ed pieces goes through before being published in the New York Times.)

You have done a disservice to economics and statistics with this article – as well as showing an almost total disregard for the other social-sciences which have produced voluminous literatures on the socio-economic causes of crime. I sincerely hope that the Irish Times will give the opportunity to someone with some expertise in this area to write a response to this article.

Friday, August 24, 2012

The GAA, Irish culture and playing by the rules

Some thoughts in response to Sean Moran's excellent article on the (non)-enforcement of rules in the GAA, and Irish society more generally.

(I posted this as a comment at the end of the article also)

The article raises a very important issue about Irish culture with regard to rules and rule-breakers. There is also an interesting parallel here with political and economic affairs in that the nearer you get to the 'top' - in whatever context - it seems, the less stringently the rules of the game are applied. 

In relation to the hurling example referred to in Sean's article, I was also disappointed with the reaction of the TV pundits on Sunday (making excuses for the violence on display and refusing to countenance the idea that this shouldn't be a part of the game). 

I fully agree with the idea that hurling is - and should remain - a physically intense contact sport. That intensity - in terms of physicality, skill and speed - is part of what makes it such an attractive sport both to play and to watch. However, it is the marriage of that intensity with - what is generally - an honest and sporting atmosphere amongst players and spectators, that sets the GAA, and hurling in particular, apart from other sports. 

I thought the GAA had begun to grow out of its adolescent need to appear "manly" at all costs. What were common practices in the past, such as mocking players for wearing white boots for example, or even for wearing a helmet, seem largely to have disappeared. But sadly, experienced analysts, all true 'hurling men' and supposedly experts on the game - cannot seem to make what should be a fairly simple distinction between a physical intensity that is fair and sporting - shoulder to shoulder challenges, pulling on the ball with both hands on the hurl etc. - as opposed to some of the cynical and ugly stuff we saw on Sunday (and in other games). The wild strokes on Michael Rice and TJ Reid were just the most egregious examples of this.

Striking your opponent with the hurl should always result in a sending off. As should interfering with another player's helmet. There is also what appears to be a fairly common practice of 'butting' your opponent with the end of the hurl - usually into the ribs or stomach - which has become the standard greeting onto the field for a newly arrived sub. This is another form of striking with the hurl which should result in a straight red card and yet seems to pass almost without comment, even when it is picked up by the cameras. 

Between the reappearance of this 'all part of the game' attitude to indiscipline and the public support from some senior GAA figures for Sean Quinn, it has been a regressive summer in terms of GAA culture.

Update: On a brighter note, this inspirational and very funny speech from Cork inter-county hurler Donal Og Cusack at the Foyle Pride Festival, represents a massive and welcome step forward for GAA and Irish culture: 

Wednesday, August 22, 2012

Scientific theory is always up for grabs

Laurence Kotlikoff (an economist at Boston University ) has written an important op-ed piece on Bloomberg about the politicization of the economics profession: "Economists risk labeling as political hacks". While I agree with the general thrust of the argument, and much of the specifics, I was troubled by the line "Economic theory isn't up for grabs". Below is my response, left as a comment after the original article.


This is an excellent article and you raise some very important points that every economist should be concerned about.

However, in the last section of the piece (titled "Consumption Spree") I think you take the argument a step too far. In particular, I have a problem with the line "Economic theory isn't up for grabs. Economic facts aren't a matter of choice." Here you are doing a disservice to economics by exaggerating its claims to scientific impartiality. No theory exists in a vacuum and empirical "facts" must be interpreted in order for them to have any meaning (this is true even for the "hard" sciences, but especially so for social science such as economics)

The preceding discussion on savings rates provides a perfect illustration of this. You take an existing theory (life cycle savings model) and use it to interpret some empirical facts (savings rates, tax incentives) resulting in an explanation of America's low savings rates. This is all perfectly valid. But it involves the selection of a model - based on a particular world view - and the interpretation of the empirical evidence through the prism of that model.

Your argument sounds convincing - and I have no doubt this is at least part of the explanation for low savings rates. But the reader - and certainly other economists - should be free to agree or disagree with your particular interpretation, and to offer alternatives. Indeed alternative explanations of low savings rates have been offered by people who start with a different model or world view and make a different interpretation of the available evidence.

This is how good science should work. It is always up for grabs.