Replication Data for: Certainty and War

This dissertation explains why a leader's certainty about adversary attributes sometimes causes peace (as conventional wisdom suggests) and sometimes causes war. Certainty facilitates bargaining and peace when the available information is sufficient to justify that certainty, as in standard rationalist accounts. However, leaders are frequently more certain than the available information warrants. These errors of overprecision can increase bargaining demands and consequently the probability of conflict. Whether leaders make overprecision errors depends on the information they solicit from senior advisers, particularly whether they collect information from those advisers with a substantive focus on adversary political, as opposed to military, attributes. I test and find support for the theory using a new measure of foreign policy elites' estimative certainty based on declassified security documents from international crises. Case studies on the Bay of Pigs and Iraq War further illustrate the logic and rule out alternative hypotheses.