Analyses of complex survey data often involve formal tests that compare means, regression coefficients or similar parameters across subpopulations. However, these tests are often motivated by substantive interest in broader questions regarding the comparability of subpopulation-level distributions. In many cases, we can address these questions through the use of quantile plots, other graphical methods and related formal tests. Implementation of this idea involves technical issues related to several components of error. Depending on the specific comparisons of interest, the proposed methods can be applied either to the distributions of individual observations, or to the distributions of related regression residuals. These ideas are illustrated with applications to the Third National Health and Nutrition Examination Survey (NHANES III).