Evaluation of Sochi 2014 Olympic medal tally forecasts: Who has won?

Fabian ten Kate, Gerard Kuper and Elmer Sterken

February 2014

 

At the Sochi 2014 Winter Games 295 medals (99 gold, 97 silver and 99 bronze) have been awarded to athletes from 26 countries in 98 events. In some events athletes have tied:

·       In the women’s downhill two gold medals are awarded (and no silver medal).

·       In the men’s super giant slalom two bronze medals are awarded.

 

Medal winning is concentrated: The Top-5 from the medal tally won 46% of the medals total, and the Top-10 won 72%. Ten countries won at least 10 medals. In this note we compare four forecasts, and focus on the Top-26.

 

Forecasts differ

There are two types of medal tally forecasts: expert’s opinions and model-based forecasts. Examples of the former are AP/Associated Press and Sports Illustrated. These journals name each gold, silver and bronze medal winner from which we compile the medal table based on the number of gold medals. Andreff and Andreff and Ten Kate, Kuper and Sterken use econometric models to generate their forecasts. An alternative to these forecasts is Infostrada who base their forecasts on world championship results.

 

It should be noted that AP/Associated Press, Sports Illustrated and Infostrada publish their forecasts just a couple of days before the start of the Winter games, while the model-based forecasts are made over a month before the start of the Games.

 

Note also that Andreff and Andreff only predict the total number medals per country. We predict the number of gold, silver and bronze medals won per country.  

 

Comparing forecasts

There are various ways to compare the forecasts. Obviously, one way is to calculate rank correlation coefficients between the various ranking of countries and the actual ranking. Table 1 presents Kendall rank correlation coefficients for the Top-26 countries. To compare our rank with Andreff and Andreff we base the rank correlation coefficients based on the rank of total medals.

 

The export forecasts outperform the model-based forecasts. Of the model-based forecasts Ten Kate, Kuper & Sterken outperform Andreff & Andreff.

 

Table 1 – Kendall rank correlation coefficients for the Top-26 countries

 

Ranked on gold-silver-bronze

- Sports Illustrated                             0.606

- Infostrada                                        0.575

- AP/Associated Press                       0.578

- Ten Kate, Kuper & Sterken            0.317

- Andreff & Andreff                                 -

 

Ranked on total medals

- Ten Kate, Kuper & Sterken            0.662

- Andreff & Andreff                          0.535  

 

We also compute Mean Squared Errors for gold, silver, bronze, and the total number of medals. The results are in Table 2. The table shows that the experts of Sports Illustrated perform best, while the model-based forecasts of Ten Kate Kuper & Sterken just outperforms Andreff & Andreff.

 

Table 2 – Mean Squared Errors (MSE) for the Top-26 countries

 

Gold

Silver

Bronze

Total

Ten Kate, Kuper & Sterken

8.96

7.58

7.88

25.88

Sports Illustrated

3.19

5.12

8.19

21.50

AP/Associated Press

5.42

7.58

4.42

26.88

Infostrada

6.50

7.04

10.38

31.92

Andreff & Andreff

-

-

-

26.85

 

Forecasts for Russia and TeamNL

We look more closely the medal forecasts for the home country and for the Netherlands. Table 3 compares these country forecasts with the realisations.

 

Table 3 – Medal forecasts for individual countries

 

Russia

Rank

Gold

Silver

Bronze

Total

Realisations

1

13

11

9

33

Forecasts:

 

- Ten Kate, Kuper & Sterken

1

15

7

13

35

- Sports Illustrated

4

9

10

6

25

- AP/Associated Press

4

10

14

9

33

- Infostrada

5

6

7

4

17

- Andreff & Andreff

4

-

-

-

24

 

Netherlands

Rank

Gold

Silver

Bronze

Total

Realisations

5

8

7

9

24

Forecasts:

 

- Ten Kate, Kuper & Sterken

7

6

5

3

14

- Sports Illustrated

6

7

4

2

13

- AP/Associated Press

7

6

3

5

14

- Infostrada

6

5

4

4

13

- Andreff & Andreff

14

-

-

-

6

 

 

Conclusion

In terms of both the rank as well as MSE Sports Illustrated outperforms the other forecasts of Olympic medal tallies. Ten Kate, Kuper and Sterken outperforms Andreff and Andreff both on forecasting the rank, as well as the MSE for total medals. Ten Kate, Kuper and Sterken is the only forecast that ranks Russia on first place in the medal table. Not surprisingly, none of the forecasts came even close to the extraordinary medal haul by TeamNL.