There's a difference between binary and open-ended predictions. "Will the iPhone be a commercial success?" is easier than "How many iPhones will be sold?". It's

There's a difference between binary and open-ended predictions. "Will the iPhone be a commercial success?" is easier than "How many iPhones will be sold?". It's the later that matters when you are directly involved. This can lead to seemingly paradox statements like "The iPhone will most likely fail, but assuming that it doesn't, it will be wildly successful". Philip Tetlock and some controversial author have written a paper about it: http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2284964 http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2284964