We present a simple method for estimating regressions based on recursive extensive-form games. Our procedure, which can be implemented in most standard statistical packages, involves sequentially estimating standard logits (or probits) in a manner analogous to backwards induction. We demonstrate that the technique produces consistent parameter estimates and show how to calculate consistent standard errors. To illustrate the method, we replicate Leblang's (2003) study of speculative attacks by financial markets and government responses to these attacks.

The dominant approach to studying the effects of IMF programs has emphasized moral hazard, but we find that adverse selection has more impressive effects. We propose a novel strategic selection model to study the growth effects of IMF programs, which allows for the possibility of adverse selection. We find that adverse selection occurs: the countries that are most interested in participating in IMF programs are the least likely to have favorable growth outcomes. Controlling for this selection effect, we find that countries benefit from IMF programs on average in terms of higher growth rates, but that some countries benefit from participation, while others are harmed. Moral hazard predicts that long-term users of Fund resources benefit least from participating in programs, while adverse selection predicts the opposite. Contrary to previous findings, we find that IMF programs have more successful growth performance among long-term users than among short-term users.

Uncertainty is pervasive in international politics. This uncertainty can have many sources. Each source has different origins and implications for the likelihood of conflict. Existing theories focus on three sources: (1) uncertainty due to asymmetric information about adversary traits that affect war payoffs, (2) uncertainty about adversary intentions, and (3) fundamental uncertainty about conflict-relevant processes. Scholarship details the implications of each type of uncertainty for war and peace as well as the prospects for reducing the uncertainty. While theoretical work is quite rich, empirical studies generally lag behind due to measurement challenges and difficulties in specifying clear, testable implications. Nonetheless, using novel proxies for different forms of uncertainty has generated notable progress.

We develop a formal model of bargaining between two states, where one can invest in a program to develop nuclear weapons and the other imperfectly observes its efforts and progress over time. In the absence of a nonproliferation deal, the observing state watches the former's program, waiting until proliferation seems imminent to attack. Chance elements-when the program will make progress and when the other state will discover this-determine outcomes. Surprise proliferation, crises over the suspected progress of a nuclear program, and possibly "mistaken" preventive wars arise endogenously from these chance elements. Consistent with the model's predictions and contrary to previous studies, the empirical evidence shows that the progress of a nuclear program and intelligence estimates of it explain the character and outcomes of most interactions between a proliferant and a potential preventive attacker. Counterintuitively, policies intended to reduce proliferation by delaying nuclear programs or improving monitoring capabilities may instead encourage it.

We present a model of the relationship between the spread of new military technologies and the occurrence of war. A new technology could shift the balance of power, causing anticipatory war as one side tries to prevent the other from obtaining it. When one side already has it, war is more likely when the shift in power is large, likely, and durable. When neither side has it, war is more likely when the expected shift is asymmetric (e.g., one side is more likely to get it) and when the two sides fear that a war will occur once one of them has it. We illustrate the model with historical examples from the spread of firearms (the Musket Wars in pre-colonial New Zealand) and of nuclear weapons (the end of US nuclear monopoly, and the 1967 Six-Day War). A broader implication is that major power competition can unintentionally cause wars elsewhere. * Comments are welcome and should be sent to mbas@gov.harvard.edu and acoe@fas.harvard.edu. We are grateful to