In a complete information setting we show that the standard lottery–in which each lottery ticket is offered for the same price–is an optimal fundraising mechanism in the presence of strong asymmetries in the way bettors value the prize and the public good provided with the lottery proceeds....

We describe an ambiguity hedging problem in Ellsberg experiments, where combinations of individually ambiguous bets eliminate aggregate ambiguity, and which may yield incorrect classifications of ambiguity averse subjects. We propose a new classification consistent with this hedging possibility.

Providing incentives to subjects in internet experiments can be tricky. One simple method is a high score (as in computer games). We test whether high scores provide adequate incentives in comparison to the usual performance based incentives. We find significant differences.