NBER Working Papers by Gregory Lewis

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Working Papers

February 2016Just Starting Out: Learning and Equilibrium in a New Market
with Ulrich Doraszelski, Ariel Pakes: w21996
We document the evolution of the newly created market for frequency response within the UK electricity system over a six-year period. Firms competed in price while facing considerable initial uncertainty about market demand and rival behavior. We show that over time prices stabilized, converging to a rest point that is consistent with equilibrium play, and then adjusted to subsequent changes in the market quite quickly. We draw on models of fictitious play and adaptive learning to analyze how this convergence occurs and show that these models predict behavior better than Nash equilibrium prior to convergence.
December 2012Buy-it-now or Take-a-chance: Price Discrimination through Randomized Auctions
with L. Elisa Celis, Markus M. Mobius, Hamid Nazerzadeh: w18590
Increasingly detailed consumer information makes sophisticated price discrimination possible. At fine levels of aggregation, demand may not obey standard regularity conditions. We propose a new randomized sales mechanism for such environments. Bidders can "buy-it-now" at a posted price, or "take-a-chance" in an auction where the top d > 1 bidders are equally likely to win. The randomized allocation incentivizes high valuation bidders to buy-it-now. We analyze equilibrium behavior, and apply our analysis to advertiser bidding data from Microsoft Advertising Exchange. In counterfactual simulations, our mechanism increases revenue by 4.4% and consumer surplus by 14.5% compared to an optimal second-price auction.
December 2011Moral Hazard, Incentive Contracts and Risk: Evidence from Procurement
with Patrick Bajari: w17647
Deadlines and penalties are widely used to incentivize effort. We model how these incentive contracts affect the work rate and time taken in a procurement setting, characterizing the efficient contract design. Using new micro-level data on Minnesota highway construction contracts that includes day-by-day information on work plans, hours actually worked and delays, we find evidence of moral hazard. As an application, we build an econometric model that endogenizes the work rate, and simulate how different incentive structures affect outcomes and the variance of contractor payments. Accounting for the traffic delays caused by construction, switching to a more efficient design would substantially increase welfare without substantially increasing the risk borne by contractors.

Published: Moral Hazard, Incentive Contracts, and Risk: Evidence from Procurement Gregory Lewis Harvard University and NBER Patrick Bajari Review of Economic Studies (2014) 81 (3): 1201-1228. citation courtesy of

April 2009Procurement Contracting with Time Incentives: Theory and Evidence
with Patrick Bajari: w14855
In public sector procurement, social welfare often depends on the time taken to complete the contract. A leading example is highway construction, where slow completion times inflict a negative externality on commuters. Recently, highway departments have introduced innovative contracting methods based on scoring auctions that give contractors explicit time incentives. We characterize equilibrium bidding and efficient design of these contracts. We then gather an extensive data set of highway repair projects awarded by the California Department of Transportation between 2003 and 2008 that includes both innovative and standard contracts. Comparing similar con- tracts in which the innovative design was and was not used, we show that the welfare gains to commuters from quicker completion substan...

Published: Gregory Lewis & Patrick Bajari, 2011. "Procurement Contracting With Time Incentives: Theory and Evidence," The Quarterly Journal of Economics, Oxford University Press, vol. 126(3), pages 1173-1211. citation courtesy of

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