1001 PredictionBook Nights

gwern

I explain what I've learned from creating and judging thousands of predictions on personal and real-world matters: the challenges of maintenance, the limitations of prediction markets, the interesting applications to my other essays, skepticism about pundits and unreflective persons' opinions, my own biases like optimism & planning fallacy, 3 very useful heuristics/approaches, and the costs of these activities in general.

Plus an extremely geeky parody of Fate/Stay Night.

This essay exists as a large section of my page on predictions markets on gwern.net: http://www.gwern.net/Prediction%20markets#1001-predictionbook-nights

I explain what I've learned from creating and judging thousands of predictions on personal and real-world matters: the challenges of maintenance, the limitations of prediction markets, the interesting applications to my other essays, skepticism about pundits and unreflective persons' opinions, my own biases like optimism & planning fallacy, 3 very useful heuristics/approaches, and the costs of these activities in general.

Plus an extremely geeky parody of Fate/Stay Night.

This essay exists as a large section of my page on predictions markets on gwern.net: http://www.gwern.net/Prediction%20markets#1001-predictionbook-nights

Another problem:

After fall of Tripoli and 90% of Libya falling under control of NTC, intrade contract that "Muammar al-Gaddafi to no longer be leader of Libya before midnight ET 31 Aug 2011" was getting lower each day intrade did not close it as done, since it became the contract that "intrade will not fuck up judging".

There was zero disagreement about facts and predictions of facts on the ground, everybody agreed that Gaddafi's government fell, so it turned into very heavy trading about intrade's sanity, and people estimated chance of sane judgment as ~67% event.

Intrade judged sanely that time, but with so much distrust in judges, prediction markets on anything more clear-cut than election results simply cannot work.

In one of previous threads about it, SilasBarta had an example where intrade fucked up, so I doubt this is an off chance.

Japan to announce it has acquired a nuclear weapon before midnight ET on 31 Dec 2011: 11% chance

Japan to announce it has acquired a nuclear weapon before midnight ET on 31 Dec 2012: 15% chance

Japan to announce it has acquired a nuclear weapon before midnight ET on 31 Dec 2013: 5% chance

This was found here at 07:45, 10/18/2011.

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