Temporal Validity in Online Social Science
The centrality of the internet to modern life means that the social and political world is changing faster and less predictably than ever before. At the same time, the “credibility revolution” has forced social scientists to confront the limits of our methods for creating knowledge. The interaction of these two trends is not yet well understood. I argue that the increasing rate of change of the objects of our study makes “knowledge decay” a potentially large source of error. “Temporal validity” is a form of external validity in which the target setting is in the future— which, of course, is always the case.