We set out to construct a test of the backdoor hypothesis that conferred as much internal and external validity as possible. In this regard, the methodology of the content analysis is sound, and its results are clear-cut. Because of the experimental design employed in the survey component of the study, the observed associations between the type of article read and belief in essential racial differences cannot be attributed to confounding factors, and we can be confident that these associations reflect the causal impact of the story content. Because the experiment was embedded in a nationally representative survey and because the results were relatively constant across sociodemographic subgroups of the population, we can conclude that the findings are reasonably representative of the adult U.S. population.
