Personality traits are patterns of thought, emotion, and behavior that are relatively consistent over time and across situations. Judging the traits of others and of oneself is a ubiquitous and consequential activity of daily life, which raises two important questions. First, how does accurate personality judgment happen? According to the Realistic Accuracy Model ( RAM), accuracy in such judgments is achieved when relevant behavioral information is available to and detected by a judge who then utilizes that information correctly. Second, when are personality judgments accurate? The RAM identifies four principal moderators of accurate personality judgment, which are properties of the target of judgment, the trait that is judged, the information upon which the judgment is based (i.e., its quantity and quality), and the individual making the judgment. People usually manage to make personality judgments that are accurate enough for navigation of the complex social world; research on accuracy seeks to understand how and when this happens.