Two B-School economics professors, Andrew Bernard and Meghan Busse, constructed an economic model of Olympic medal-winning that was recently published in the Review of Economics and Statistics. Since there's no better way to test a model than by forecasting, the authors put on the Web their forecast for this year's Games.

How did they do?

Below I list their forecasts for the 34 countries on their Web page and the actual result. In a third column, "naive forecast", are listed the number of medals won by each country in the last Summer Olympics.

The mean square error of Bernard and Busse: 28.5.
The mean square error of the naive, no-change forecast (not including the last three nations): 25.6.

Oh, well . . .

(To be fair, their model missed badly on just two countries, Greece and Japan, and they thought Greece would benefit a lot from being the host. Without Greece, the naive model's MSE is 25.4 and their model's MSE is 24.9. And they also forecast just the number of gold medals. There, even with Greece included, their model outperforms no-change by 9.6 to 10.9)

	Naïve Model	Bernard & Busse	Actual
U.S.	97	93	103
Russia Fed.	88	83	92
China	59	57	63
Germany	57	55	48
Australia	58	54	49
France	38	37	33
Italy	34	33	32
U.K.	28	27	30
Greece	13	27	16
South Korea	28	27	30
Cuba	29	25	27
Romania	26	23	19
Netherlands	25	21	22
Ukraine	23	20	23
Japan	18	19	37
Hungary	17	14	17
Belarus	17	13	15
Canada	14	13	12
Poland	14	12	10
Brazil	12	12	10
Spain	11	11	19
Sweden	12	11	7
Bulgaria	13	10	12
Norway	10	8	6
Switzerland	9	8	5
Czech Rep.	8	6	8
Mexico	6	6	4
Indonesia	6	6	4
Ethiopia	8	5	7
Kazakhstan	7	5	8
Denmark	6	5	8
Kenya	7	4	7
Jamaica	7	3	5
Georgia	6	3	4
Turkey	4		10
Poland	14		10
Thailand	3		8