Standard incentive theory models provide a rich framework for studying informational problems but assume that contracts can be perfectly enforced. This paper studies the design of self-enforced relational contracts. I show that optimal contracts often can take a simple stationary form, but that self-enforcement restricts promised compensation and affects incentive provision. With hidden information, it may be optimal for an agent to supply the same inefficient effort regardless of cost conditions. With moral hazard, optimal contracts involve just two levels of compensation. This is true even if performance measures are subjective, in which case optimal contracts terminate following poor performance.

We develop a model in which firms set impersonal salary levels before matching with workers. Wages fall relative to any competitive equilibrium while profits rise almost as much, implying little inefficiency. Furthermore, the best firms gain the most from the system while wages become compressed. In light of our results, we discuss the performance of alternative institutions and the recent antitrust case against the National Resident Matching Program.

We describe a two-step algorithm for estimating dynamic games under the assumption that behavior is consistent with Markov perfect equilibrium. In the first step, the policy functions and the law of motion for the state variables are estimated. In the second step, the remaining structural parameters are estimated using the optimality conditions for equilibrium. The second step estimator is a simple simulated minimum distance estimator. The algorithm applies to a broad class of models, including industry competition models with both discrete and continuous controls such as the Ericson and Pakes (1995) model. We test the algorithm on a class of dynamic discrete choice models with normally distributed errors and a class of dynamic oligopoly models similar to that of Pakes and McGuire (1994).

We compare the costs and benefits of profit-sharing partnerships relative to the corporate form of organization. We show that organizing as a partnership can be desirable in human-capital intensive industries where product quality is hard to observe. The theory explains the relative scarcity of partnerships outside of professional service industries such as law, accounting, medicine, investment banking, architecture, advertising, and consulting. It also sheds light on features of partnerships such as up-or-out promotion systems, the use of non-compete clauses, motives for profit sharing as well as recent trends in professional service industries

The past decade has seen the explosive emergence of online advertising as a major source of revenue for Internet publishers. Analyses of this phenomenon are mostly conducted in the sway of Google’s hugely successful search advertising program. In the early days of the Internet, before Google, virtually all advertising revenues were related to simple display ads. Yet by 2008 search advertising accounted for over $10.5 billion of the $23.4 billion in total online advertising, and pundits were forecasting continued growth at rates of 12 % per year over the next five years.1 Internet advertising markets have broken sharply from the advertising markets for traditional media. In the older media, every consumer that received a particular magazine, listened to a particular radio program, or watched a particular TV show would read, hear or see the same advertisement. An advertiser that wanted to reach an audience with particular characteristics could do so only within narrow limits. For example, a beer company might advertise on televised football games and a maker of fashion clothing might advertise in women's magazines. Although publications do some tailoring of their offerings, as when a newspaper has different local editions, audience mix is nevertheless

This paper analyzes the role of private information in U.S. Forest Service timber auctions. In these auctions, firms bid a per unit price for each timber species. Total bids are computed by multiplying these prices by Forest Service volume estimates, but payments depend on actual volumes harvested. We develop an equilibrium theory for these auctions. We then relate (ex post) data about volume to (ex ante) bids. We show that bidders have private information about volumes of species and use it as predicted by theory. Differences in bidder estimates appear to affect the allocation of tracts, but competition limits information rents.

We present new evidence on consumer liquidity constraints and the credit market conditions that might give rise to them. We analyze unique data from a large auto sales company serving the subprime market. Short-term liquidity appears to be a key driver of consumer behavior. Demand increases sharply during tax rebate season and purchases are highly sensitive to down-payment requirements. Lenders also face substantial informational problems. Default rates rise significantly with loan size, providing a rationale for loan caps, and higher-risk borrowers demand larger loans. This adverse selection is mitigated, however, by risk-based pricing. (JEL D14, D82, D83, G21)

Premiums in health insurance markets frequently do not reflect individual differences in costs, either because consumers have private information or because prices are not risk rated. This creates inefficiencies when consumers self-select into plans. We develop a simple econometric model to study this problem and estimate it using data on small employers. We find a welfare loss of 2-11 percent of coverage costs compared to what is feasible with risk rating. Only about one-quarter of this is due to inefficiently chosen uniform contribution levels. We also investigate the reclassification risk created by risk rating individual incremental premiums, finding only a modest welfare cost.

We estimate the sensitivity of Internet retail purchasing to sales taxes using eBay data. Our first approach exploits the fact that a seller's location—and therefore the applicable tax rate—is revealed only after a buyer has expressed interest in an item. We document how adverse tax “surprises” reduce the likelihood of purchase and shift subsequent purchases toward out-of-state sellers. We then use more aggregated data to estimate that every one percentage point increase in a state's sales tax increases online purchases by state residents by almost 2 percent, while decreasing their online purchases from state retailers by 3–4 percent. (JEL H71, L81, L86)

We estimate the economic surplus created by the Medicare Advantage program under its reformed competitive bidding rules. We use data on the universe of Medicare beneficiaries and develop a model of plan bidding that accounts for both market power and risk selection. We estimate that the Medicare Advantage program generates substantial surplus to participants (of $217 per enrollee-month), but that approximately two-thirds of this surplus is captured by insurers. We use the model to evaluate the impact of possible program changes, including changes that could increase competition and lead to lower profits and higher consumer surplus without raising taxpayer costs.