An experiment analyzing behavior in English common value auctions is reported. English auctions raise more revenue than first-price auctions only when bidders do not suffer from a strong winner's curse. Agents employ other bidders' dropout prices along with their private information as Nash bidding theory predicts. However, a simple and natural signal-averaging rule, that does not require recognizing the adverse-selection effect of winning the auction, better characterizes the data than the Nash rule. Monte Carlo simulations using FIML estimates of the signal-averaging rule predict a number of data characteristics not directly employed in the estimation procedure.

Bidder coalitions at English auctions frequently distribute collusive gains among members via a secondary auction or "knockout." When coalition members are sufficiently heterogeneous, nested coalition structures are observed in which a knockout is conducted at each level of nesting. The nested knockout's characteristics are investigated. Within many settings we find that the expected payments to coalition members via the nested knockout equal the Shapley value. Incentive compatibility problems of the nested knockout are also analyzed.

The encompassing principle is used to develop a testing framework which unifies the literature on non-nested testing, allowing analysis of the relationship between alternative tests and in particular enabling asymptotic and finite sample equivalences and identities to be established easily when they exist, as well as embracing nested hypothesis testing. The concept of the implicit null hypothesis of a test is introduced to show that the effective acceptance region for some tests extends beyond the acceptance region corresponding to the null of interest, and so such tests can be inconsistent against fixed alternatives closely related to the nominal null and alternative. The analysis is illustrated by an application to two non-nested linear regression models, and it is shown that the conventional F test, as well as all the one degree of freedom non-nested tests, has an encompassing interpretation, and that the F test is a complete parametric encompassing test.

Super-experienced bidders have learned to overcome the winner's curse but still earn less than 50% of Nash equilibrium profits. Subjects deviate from the complicated Nash strategy, employing piecewise-linear bid functions that are capable, in principle, of generating an equilibrium with average profits at or above the Nash benchmark. Thus, limited computational abilities alone cannot account for the reduced earnings. Further, subjects are far from best responding within this family of piecewise-linear bid functions. Alternative factors contributing to these reduced earnings are explored.

We develop a model of GDP growth under which regime changes are triggered stochastically by an observable tension index, constructed as the geometric sum of deviations of actual GDP growth from a corresponding sustainable rate. Within expansionary regimes, the tension index tends to increase, which heightens the probability of a regime change. Given a regime change, the process becomes reversed, and the tension index begins to decline along a newly established path. Linking the behavior of the tension index to GDP growth enables us to capture floor and ceiling effects.

Allegations of Bidder collusion at Forest Service timber sales in the Pacific Northwest were common in the 1970s. Of course, prices may be low for reasons other than collusion. We formulate an empirical model that allows for both bidder collusion and supply effects and in which we control for demand conditions. Noncooperative behavior in which a single unit is sold (the standard auction model) is a special case: it is found to be definitively outperformed by a model of collusion. We also find that supply effects are dominated by collusion in determining the winning bids in the market.

[Definitions are proposed for weak and strong exogeneity in terms of the distribution of observable variables. The objectives of the paper are to clarify the concepts involved, isolate the essential requirements for a variable to be exogenous, and relate them to notions of predeterminedness, strict exogeneity and causality in order to facilitate econometric modelling. Worlds of parameter change are considered and exogeneity is related to structural invariance leading to a definition of super exogeneity. Throughout the paper, illustrative models are used to exposit the analysis.]