Olympic-medal forecasting is a crowded field.
A variety of institutions have come up with predictions for Rio 2016. Practically all put the US in first place on the medal count, followed by China. Some are calling third place for Great Britain; others for Russia, though those estimates probably don’t take into account that dozens of athletes from that country have been banned from the Olympics for doping.
Three days before the closing ceremony, it looks like forecasters’ top rankings will be close to the actual results. Here are the odds calculated by PwC, Goldman Sachs and researchers at Germany’s RWI economic research institute compared to the medals won so far.
Most of the prediction models incorporate factors such as the size of a country’s population and its wealth. The bigger the pool of athletes, the more likely a star will be among them. Citizens from richer countries can afford to spend more on getting good at sports, and their governments have more resources to spare to support them. Researchers have also found a clear correlation between communist countries and medal count; thus, the oversized punch from Cuba. The small island nation has racked up nine medals so far.
Then, there’s the substantial home advantage. China increased its medal count to 100 during Beijing 2008 compared to 63 the previous Olympics in Athens; and Great Britain snatched 65 in London 2012 vs 47 in Beijing.
Past models that take those factors into account have proven fairly effective. Goldman Sachs perfectly predicted the UK’s total tally of 65 medals in London 2012, as well as the top 11 medal-winning countries, it said in a report. An economist at Tuck School of Business at Dartmouth created a model with a 96% accuracy rate (pdf) in the Sydney and Athens games.
But in the end, who won last time around turns out to be a pretty decent indicator of who will win this time, regardless of all the other variables. A study led by RWI’s Julia Bredtmann found that a “naive” model solely based on past performance was nearly as accurate as a more sophisticated version that considered a range of factors.
The sophisticated model was better at forecasting the number of medals for the top-performing countries, according to the paper, which was published in June in statistics journal Significance. But both accurately predicted which national teams would be the biggest winners in the London Olympics in 2012, even if not in the exact order.
Though economists say citizens of nations that don’t traditionally win shouldn’t be too discouraged by statistical determinism. “David can sometimes beat Goliath in the Olympic arena,” said PwC’s John Hawksworth in the firm’s report. There’s already a few examples in these Olympics: Thailand has scored six Olympic medals, nearly as many as in the past two Olympics combined. Bahrain, hardly an Olympic favorite, has won two—largely because it got African athletes to compete on its behalf. Five countries have also won their first ever gold, which for some represents their first Olympic medal of any color.
Alas, countries can also defy the odds to their detriment. Nations that should do well by the numbers sometimes don’t. Take Mexico: It’s the world’s 15th largest economy, the 10th most populous nation, and it won seven medals during the London Games. But it’s only secured one so far in Rio. India has similarly underperformed. Its medal count so far: a single bronze, though by making it to the finals, a badminton player has also guaranteed a silver.
In contrast, Colombia, with a much smaller population and two-thirds of Mexico’s per capita GDP, has earned five medals. Even tiny Armenia, with its three million residents vs. India’s 1.3 billion, has won four medals, including one gold.
Part of the problem for India and Mexico is that sports authorities appear to have misplaced their priorities, sometimes in embarrassing fashion. For example, while some Indian officials stretched out in business class on the long flight to Rio, athletes were sent in coach. Some Mexican competitors had to appear in patched-up everyday uniforms or buy new ones on credit because authorities failed to supply what they needed. Meanwhile, the head of Mexico’s sports agency clad his apparent girlfriend with the Mexican delegation’s official outfit.
It’s hard to statistically account for the toll that kind of self-importance takes on athletes’ performance.