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In law, we commonly presume that judges reach decisions based on legal materials, such as precedents. In political science, researchers typically presume that judges do not reach decisions based on such legal materials. They maintain that the apparent reliance on precedent to reach decisions is simply a hoax designed to provide cover for a particular outcome. These researchers traditionally argued that judges reach their personally preferred outcome in the case and then rationalize it after the fact with references to precedent, conveniently supplied them by the attorneys for their preferred side. Much of the empirical research on judicial decision making has involved the United States Supreme Court. Indeed, there is considerable evidence that Supreme Court justices decide cases differently, for ideological reasons, and do not reliably defer to prior precedents of the Court. For structural reasons, though, the Supreme Court is not a representative sample to study the operation of the law. The Court selects its own cases, and very few of them. These are often the cases where the law does not provide a clear answer, so one cannot look for legal control. Moreover, in its position at the top of the judicial hierarchy, the Supreme Court has no vertically superior precedents it is legally bound to obey. The lower courts are where the law is found in this nation. They issue vastly more decisions and the appellate courts are often the final arbiters of legal disputes, on the frequent occasions when the Supreme Court does not review their rulings. Political scientists and economists have considered the role of precedent in lower courts. Although loath to accept claims that judges follow precedent because they are supposed to do so, these researchers have argued that lower-court judges do indeed follow precedent, for strategic reasons.