It doesn't matter whether the estimates were made in terms of percentages or proportions
It also doesn't matter whether the estimates resolved by a binary truth (e.g. "What's the probability David Cameron will still be UK Prime Minister on Jun 1 2014?") or whether the truth can range anywhere from 0% to 100% (e.g. "What percent of votes will Barack Obama get in the 2012 Presidential Election"?).
I also need to be able to find out the ground truth that resolves the estimation - e.g. I can go and look up what percent of votes Obama got.
There's no need for the questions to be political; they could be about anything.