The Great Lakes questions have resolved.
What will be the peak mean ice concentration in Lake Ontario during the 2013/2014 winter? has resolved as “56% or greater”. Data from NOAA coastal watch indicates Lake Ontario ice concentration hit 61.52%.
Analysis of the Predictions
Our raw market Brier Score (before smoothing or adjustments) was .75.
The Brier Score (Brier 1950) is a measurement of the accuracy of probabilistic predictions. As a distance metric, a lower score is better than a higher score. The market Brier Score ranges from 0 to 2, and is the sum of the squared differences between the individual forecasts and the outcome weighted by how long the forecasts were on the market. On a binary (Yes/No) question, simply guessing 50% all the time yields a “no courage” score of 0.5. These questions used the Ordered Brier, officially known as the Ranked Probability Score (RPS).
There were 28 forecasts made by 4 unique users.
There were 2 participants’ comments. Here is one:
Both Lake Ontario and Lake Michigan have exceeded their questions’ threshold for the “over” answer, and should resolve at that answer.
Additional Great Lakes Questions and Resolutions:
Click the questions to see the discussion comments, background, trends and history.
The “96%-97%” answer has resolved as true for this question. Data from NOAA coastal watch indicates Lake Erie ice concentration hit 96.4% in early March. Source.
This question had 53 forecasts by 10 unique users, 3 comments and a Brier Score of 0.29.
The “88% or greater” answer has resolved as true for this question. Data from NOAA coastal watch indicates Lake Michigan ice concentration recently hit 92.98%! Source.
This question had 22 forecasts by 5 unique users, 2 comments and a Brier Score of 0.69.
The “95%-96%” answer has resolved as true for this question. Data from NOAA coastal watch indicates Lake Superior ice concentration hit 95.74% in early March. Source.
This question had 61 forecasts by 12 unique users, 3 comments and a Brier Score of 0.20.
It’s curious that two of these questions did relatively well (scores 0.2 or 0.3) while two did relatively poorly (0.7 and 0.75). Presumably the same sort of data was available for all. Forecasters: were some lakes harder to predict?
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