Nicolas S. Lambert

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We investigate the problem of truthfully eliciting an expert's assessment of a property of a probability distribution, where a property is any real-valued function of the distribution such as mean or variance. We show that not all properties are elicitable; for example, the mean is elicitable and the variance is not. For those that are elicitable, we(More)
We examine a class of wagering mechanisms designed to elicit truthful predictions from a group of people without requiring any outside subsidy. We propose a number of desirable properties for wagering mechanisms, identifying one mechanism - weighted-score wagering - that satisfies all of the properties. Moreover, we show that a single-parameter(More)
We analyze the computational complexity of market maker pricing algorithms for combinatorial prediction markets. We focus on Hanson's popular logarithmic market scoring rule market maker (LMSR). Our goal is to implicitly maintain correct LMSR prices across an exponentially large outcome space. We examine both permutation combinatorics, where outcomes are(More)
We consider the problem of truthfully sampling opinions of a population for statistical analysis purposes, such as estimating the population distribution of opinions. To obtain accurate results, the surveyor must incentivize individuals to report unbiased opinions. We present a rewarding scheme to elicit opinions that are representative of the population.(More)
Prosper, the largest online social lending marketplace with nearly a million members and $178 million in funded loans, uses an auction amongst lenders to finance each loan. In each auction, the borrower specifies <i>D</i>, the amount he wants to borrow, and a maximum acceptable interest rate <i>R</i>. Lenders specify the amounts <i>a<sub>i</sub></i> they(More)
Suppose a principal Alice wishes to reduce her uncertainty regarding some future payoff. Consider a self-proclaimed expert Bob that may either be an informed expert knowing an exact (or approximate) distribution of a future random outcome that may affect Alice's utility, or an unin-formed expert who knows nothing more than Alice does. Alice would like to(More)
Prosper, the largest online social lending marketplace with over a million members and $207 million in funded loans, uses an auction amongst lenders to finance each loan. In each auction, the borrower specifies D, the amount he wants to borrow, and a maximum acceptable interest rate R. Lenders specify the amounts a i they want to lend, and bid on the(More)
We construct a budget-balanced wagering mechanism that flexibly extracts information about event probabilities, as well as the mean, median and other statistics from a group of individuals. We show how our mechanism, called Brier betting mechanism, arises naturally from a modified parimutuel betting market. We prove that it is essentially the unique(More)
We study trading behavior and the properties of prices in informationally complex markets. Our model is based on the single-period version of the linear-normal framework of [Kyle 1985]. We allow for essentially arbitrary correlations among the random variables involved in the model: the true value of the traded asset, the signals of strategic traders, the(More)