In his thoughtful focus article, Haertel (this issue) pushes testing experts to broaden the scope of their validation efforts and to invite scholars from other disciplines to join them. He credits existing validation frameworks for helping the measurement community to identify incomplete or nonexistent validity arguments. However, he notes his sense that something is missing in these frameworks, particularly as they seem to identify questionable, poorly articulated, or inappropriate uses only after the milk, as it were, has been spilled. The author found Haertel's description of these uses helpful, particularly his identification of "indirect actions" of tests that have been a blind spot, by accident or by design, for validation efforts. His piece represents a call to action for testing experts to embrace more responsibility for validation and forge new alliances to get the work done. In this brief response, the author tries to maintain the momentum that Haertel (this issue) initiates by identifying and then loosening what he sees as a blockage point in current efforts to do what Haertel proposes. Like Haertel (this issue), the author believes that testing experts have been limiting their vision by waiting for others to articulate and validate interpretive arguments for rapidly proliferating test uses. He argues that validation frameworks are missing a theory about how test uses change. The perspective on modern test-score usage that he finds most helpful is epidemiological. Numbers travel. They aggregate and spread. This spread is not random. Numbers travel and aggregate along vectors, and their spread is facilitated by known risk factors. The more testing experts understand about the tendency of test usage to propagate along known vectors, the better they are able to anticipate or require validation. The author acknowledges that the comparison of the proliferation of test score uses to an influenza epidemic is not perfect, but he hopes it is instructive nonetheless.