Football referees aren’t just wrong, they’re biased

Football penalties are often controversial and the first couple of days of the World Cup have already provided one dubious decision. Luckily for the referee’s personal safety it favoured the hosts, Brazil. But, according to Randal Olson’s fascinating analysis of penalty decisions, there may be more than luck involved:

70.6% of all penalty kicks were awarded to the Home team.


Similarly, if the Away team received the first penalty kick, then the Home team received the second penalty kick 92.5% of the time — an incredible display of referee bias.

Check out the whole post for all the details and a bunch more stats!

Rule design in professional cycling

Via Lars Christensen, here is a combination of my favourite things:

Sprint finishes in professional cycling are fast, furious, and dangerous. A “red flag rule” seeks to moderate the chaos of these finishes, but may induce moral hazard by removing the time penalty associated with crashing. To test for moral hazard, the authors use a 2005 rule change that moved the red flag from 1 km to 3 km from the finish. Data from Europe’s Grand Tours indicate that, after the rule change, both the incidence and the size of crashes nearly doubled in the 1–3 km from the finish zone. There was no such increase in crashing rates in the 3–5 km zone.

Warning: Sports nerdiness follows. Read more

Ethics of doping

Peter Singer on doping in sport:

At the elite level, the difference between being a champion and an also-ran is so miniscule, and yet matters so much, that athletes are pressured to do whatever they can to gain the slightest edge over their competitors. It is reasonable to suspect that gold medals now go not to those who are drug-free, but to those who most successfully refine their drug use for maximum enhancement without detection.

Julian Savulescu proposes that instead of trying to detect whether an athlete has taken drugs, we should focus on measurable indications of whether an athlete is risking his or her health. So, if an athlete has a dangerously high level of red blood cells as a result of taking erythropoietin (EPO), he or she should not be allowed to compete. The issue is the red blood cell count, not the means used to elevate it.

To those who say that this will give drug users an unfair advantage, Savulescu replies that now, without drugs, those with the best genes have an unfair advantage… Setting a maximum level of red blood cells actually levels the playing field by reducing the impact of the genetic lottery. Effort then becomes more important than having the right genes.

This discussion of the value of genes vs effort, and the morality of using drugs to level the genetic field, seems to have parallels with social redistribution. We begin unequal because of genetic differences. Through a system of taxes, subsidies, and other transfers, we redistribute the fruits of effort, genetic talent, and opportunity.

What is interesting is that most people think it is fair to redistribute some of the fruits of talent to the least lucky in society. That is why we have progressive systems of taxation, for instance. But, in the sporting arena, pure talent and opportunity is glorified and there are few serious movements to redistribute the lottery. That’s not to say there isn’t some action, but the call for more equal outcomes in sporting contests clearly not as strong as in economic contests.

AJR vs Sachs: the conflict drags on…

Acemoglu and Robinson have proven to be extremely combative bloggers but they have, until now, refrained from engaging directly with their nemesis. Well, it seems they might have been harbouring a little bit of a grudge:

Several people asked us why we haven’t responded to Jeffrey Sachs’s review of Why Nations Fail. Well the answer was sort of in-between the lines in our response to Arvind Subramanian review: we said that thoughtful reviews deserve thoughtful answers.

Grab your popcorn and head on over for the full reply!

Olympic economics

Tyler Cowen and Kevin Grier make some predictions:

  1. Medal totals will become more diversified over time. The market share of the “top 10” countries will continue to fall (it was 81 percent in 1988) as economic and population growth slows in the rich world. The developing world has greater room for rapid economic growth, and most parts of the developing world also have higher population growth. The Olympic playing field will get more and more level.
  2. Japan will continue to fade, mostly because of aging and population shrinkage.
  3. Italy will follow Japan for similar demographic reasons, as well as because the Eurozone crisis will continue to cut into budgets, training and otherwise.
  4. Since Rio is host to the next Olympics, Brazil should do better than expected due to the “pre-host” bump.
  5. Many African nations will rise. Currently about half of the approximately 1 billion people in Africa have a cell phone, and the middle class is growing. The chance that an African star will be spotted and trained at the appropriate age is much higher than before. Africa also continues to grow in population, and that means lots of young people. Most of us still think of African nations as very poor, but infant mortality has been falling and per-capita income rising across Africa for the better part of a decade now.
  6. China will level off and then decline as a medal powerhouse. In less than 15 years, the typical person living in China is likely to be older on average than the typical person living in the United States, in part due to the country’s one-child policy. As of 2009 the number of over-60s was 167 million, about an eighth of the population, but by 2050 it is expected to reach 480 million people older than 60, with the number of young Chinese falling. The country will become old before it is truly wealthy.

With some small edits that could almost serve as a prediction of the changing face of global politics, too.

Morality in sport


On Tuesday night at the London Games, some of the world’s best badminton players hit some of the sport’s worst shots. Sad serves into the net. Returns that sailed far wide. …On Wednesday, four women’s doubles teams — two from South Korea and one each from China and Indonesia — were disqualified. …The eight players were found to have tried to lose their matches intentionally, apparently because they had determined that a loss would allow them to play a weaker opponent in the next round.

I don’t really understand the moral outrage over this. The competition is set up such that winning it is easiest if you lose some matches, but there are also sporting norms that say you have to do your best to win every game. Obviously, when the rewards to winning the competition are high, those incentives will over-ride the norms of sporting conduct. It’s no surprise that teams would try to throw a match, although I am surprised that they did it so obviously: you’d think they’d practice this sort of thing a lot if most competitions work this way.

There’s a more technical discussion of incentive compatibility constraints in the design of the competition over at Cheap Talk.