Exposure is often cited as an explanation for campaign success or failure. A lack of validation evidence for typical exposure measures, however, suggests the possibility of either misdirected measurement or incomplete conceptualization of the idea. If whether people engage campaign content in a basic, rudimentary manner is what matters when we talk about exposure, a recognition-based task should provide a useful measure of exposure, or what we might call encoded exposure, that we can validate. Data from two independent sources, the National Survey of Parents and Youth (NSPY) and purchase data from a national antidrug campaign, offer such validation. Both youth and their parents were much more likely to recognize actual campaign advertisements than to claim recognition of bogus advertisements. Also, gross rating points (GRPs) for a campaign advertisement correlated strikingly with average encoded exposure for an advertisement among both youth (r = 0.82) and their parents (r = 0.53).