Epidemiological concepts can be applied to a wide variety of areas. One important concept is the false positive paradox—that even with a highly accurate disease screen, if the true incidence of the disease in the tested population is very low, most individuals who test positive may be false positives. Examples of the false positive paradox are found in many areas of injury prevention and public health generally. This essay illustrates some of the insights that the false positive paradox brings to interpreting survey-based estimates, with examples from gun research, specifically estimating the annual number of defensive gun uses, the number of people directly impacted by public mass shootings and the number of guns stolen from private individuals.