Host Nation Bounce Effect

Russia won the medal chase at the 2014 Sochi Olympics by winning 33 medals, with 13 golds, both tops, whether you use the North American or the European system. Will Russia win as many medals in 2018, or perhaps more? No.

I’ll predict right now, knowing nothing about Russian athletic performance between now and 2018, that they will win 23 medals in Pyeongchang, and probably 9 golds. How can I predict that now?

Its done by a thing I call the “Host Nation Bounce Analysis.” It has long been suspected that each nation that hosts an Olympics (and I know the IOC policy is that nations don’t host Olympics, cities do – spare me) improves their performance in the medal tables. To truly analyze this I looked at the performance of hosting nations since World War II, looking at how many medals they won at their hosting Olympics (0 in the table below), at the Olympics before they hosted (-1), and at the three Olympics after they hosted (1/2/3 below). We could easily calculate the percentage of medals and gold medals they won at each of these give Olympic Games.

In the table below I call the percentage of medals and gold medals they won at their hosting Olympics as 100%, and compared their performance, relative to the number of medals and golds available, at the other four Olympics contiguous with the one they hosted. Using current base numbers of 300 events, and 950 medals (combative sports have 2 bronze medals in most cases), we get the following estimates for medals won and percentages of medals won by host nations:

 

# G TM %G %TM %HostGM %HostTM
-1 19.0 55.0 6.33% 5.79% 57.7% 67.8%
0 32.9 81.2 10.95% 8.54% 100.0% 100.0%
1 21.5 59.6 7.17% 6.28% 65.4% 73.4%
2 15.7 47.6 5.24% 5.01% 47.7% 58.7%
3 12.5 38.6 4.17% 4.06% 38.1% 47.5%

 

So there is a definite bounce effect. Nations tend to win only about 60-70% of medals at the Olympics prior to their host Olympics. And likewise, they win less medals at the Olympics after they host. Further, this has a reasonably linear decrease over time, earning about 70% of the medals at the 1st Olympics post-hosting, and then about 55% and 40% at the 2nd and 3rd Olympics post-hosting.

Now this analysis has been done for the Summer Olympics. The reason for that is that until recently, there simply weren’t enough events at the Winter Olympics to do a solid statistical analysis, although I did look at it. With the small number of events, there is simply too much statistical noise. With the 98 events held in Sochi, this may now be eliminated, but we have only one Winter Olympics to base that on.

So considering this, I am predicting that Russia will win 70% of the number of the medals and gold medals they won in Sochi – or 23 medals and 9 gold medals. Have at it, prognosticators.

5 thoughts on “Host Nation Bounce Effect”

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