Hybrid Auctions II: Experimental Evidence

In this paper we report the results of an experiment designed to examine the properties of a hybrid auction - a Dutch-Vickrey auction, that combines a sealed bid …rst-price auction with a sealed bid second-price auction. This auction mechanism shares some important features with that used in the sale of the companies constituted through the partial division of the Telebras System - the government-owned Telecom holding in Brazil. We designed an experiment where individuals participate in a sequence of independent …rst-price auctions followed by a sequence of hybrid auctions. Several conclusions emerged from this experimental study. First, ex-post e¢ciency was achieved overwhelmingly by the hybrid auctions. Secondly, although overbidding (with respect to the risk-neutral Bayesian Nash equilibrium) was a regular feature of participants’ bidding behavior in the …rst-price auctions — as it is commonly reported in most experimental studies of …rst-price auctions, it was less frequent in the hybrid auctions. By calibrating the results to allow for risk-averse behavior we were able to account for a signi…cant part of the overbidding. Finally, we compared the revenue generated by the hybrid auction with that generated by a standard …rst-price sealed bid auction and the results were ambiguous.

Bias and size effects of price-comparison search engines : theory and experimental evidence

We analyze the impact on consumer prices of the size and bias of price comparison search engines. In the context of a model related to Burdett and Judd (1983) and Varian (1980), we develop and test experimentally several theoretical predictions. The experimental results confirm the model’s predictions regarding the impact of the number of firms, and the type of bias of the search engine, but reject the model’s predictions regarding changes in the size of the index. The explanatory power of an econometric model for the price distributions is significantly improved when variables accounting for risk attitudes are introduced.

Sistemas de custos em organizações hospitalares: estudo de casos

Esta pesquisa objetivou analisar os sistemas de custos implantados em seis hospitais gerais da cidade do Rio de Janeiro, quanto a sua estrutura e funcionamento, em relação à literatura sobre contabilidade de custos, incluindo os manuais de alguns órgãos governamentais do Brasil. Na revisão de literatura, foram abordados os aspectos e propósitos dos sistemas de custos, as regras para sua implantação, os diferentes sistemas, os métodos de custeio e, finalmente, os enfoques específicos dos sistemas de custos hospitalares (Capítulo II). Para a realização do trabalho, escolheu-se o método de estudo de casos, em razão da carência de verificações empíricas nesta área e a necessidade de uma descrição profunda dos sistemas de custos encontracos (Capítulo III). A seguir, apresentou-se a descrição dos casos, abordando-se as características individuais das unidades hospitalares e a estrutura e o mecanismo dos seus sistemas de custos (Capítulo IV). Os resultados obtidos possibilitaram analisar os tipos de sistemas implantados quanto à natureza dos custos, à forma de acumulação e aos métodos de custeio. Permitiram tambem uma análise dos procedimentos e utilização dos sistemas para fins administrativos (Capítulo V). Relacionando-se os resultados à literatura, chegou-se a importates conclusões e finalmente sugeriu-se novos estudos nesta área.

Asymmetric auctions and risk aversion within independent private valoues

We study tournaments with many ex-ante asymmetric (heterogeneous) contestants as an independent-private-values all-pay auction. The asymmetry is either with respect to the distribution of valuations for the prize or the risk preferences. By characterizing equilibria in tnonotone strategies we show that tournaments \:vith man~y heterogenous contestants are qualitatively distinct. First, with two (or many ex-ante identical) participants, a contestant always exerts some effort with positive probability. In contrast, with many asymmetric participants, one 1night not exert any effort at all, even if there is a positive probability that he has the highest valuation among ali. Second, in tournan1ents with t'wo (o r n1any ex-ante h01nogenous) contestants, equilibrium effort densities are decreasing. This prediction is at odds with experimental evidence that shows the empírica! density might be increasing at high effort levels. V\.lith rnany heterogeneous contestants, however. the increasing bid density is consistent with an equilibrium behavior.