A Quasi-Experimental Test of the Marginal Trader Hypothesis
通过比较2008年美国总统选举的预测市场与排除边际交易者的预测竞赛结果，检验边际交易者假说，发现两者预测准确度无差异，不支持该假说。
Economists have tried to reconcile irrational individual-level behavior with rational market behavior through the Marginal Trader Hypothesis (MTH), which posits that even when most traders act irrationally, a small group of well-informed traders can keep an asset's market price equal to its fundamental value. I test the MTH by comparing predictions for the 2008 U.S. presidential election generated by the Iowa Electronic Markets to those of a prediction contest, a decision task that precludes marginal traders. The results do not support the MTH; I find that the forecasts generated by the prediction market and the prediction contest are equally accurate.