This study investigated the effects and interplay of several core determinants of consensus in person perception: information overlap, information quantity, cross-situational consistency, and shared meaning. Targets (N = 200) were filmed in different standardized situations. Perceivers either watched the same target in different situations (N = 1,395 perceivers) or different targets in the same situation (N = 3,963 perceivers) and then rated the targets’ personalities after each video. Overlap of the observed situations was systematically varied across perceivers. Consensus was higher when perceivers (a) observed a target in more overlapping situations, (b) observed a target in more situations overall, judged characteristics (c) for which between-target differences were more consistent across situations, or (d) for which perceivers had more similar meaning systems. The effect of overlap was more important with low consistency or information quantity, but moderate in size overall. In light of prior research failing to adequately operationalize overlap and consider its interplay with other factors, this study presents the strongest evidence to date on these issues.