Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
People often see the same evidence but draw opposite conclusions, becoming polarized over time. More surprisingly, disagreements persist even when they are commonly known. We derive a model and present an experiment showing that opinions can diverge when one-dimensional opinions are formed from two-dimensional information. When subjects are given sufficient information to reach agreement, however, disagreement persists. Subjects discount information when it is filtered through the actions of others, but not when it is presented directly, indicating that common knowledge of disagreement may be the result of excessive skepticism about the decision-making skills of others. (JEL C92, D82, D83)