This study reported in Proc. Nat. Acad. Sci. USA 111(30):10984-10989 examined the accuracy of 1,514 strategic intelligence forecasts that were extracted from Intelligence Memoranda produced by the Intelligence Assessment Secretariat of the Privy Council Office, Government of Canada.
This data set includes information on the experience of the analyst, the rated difficulty of the forecast, the rated importance of the forecast, the temporal window of the forecast, the outcome of the forecasted event, the probabilistic forecast that was made, and a measure of forecasting accuracy (the Brier score).