Responses of inattentive or inconsistent subjects in stated-choice (SC) surveys can lead to imprecise or biased estimates. Several SC studies have investigated inconsistency and most of these studies dropped subjects who were inconsistent. However, none of these studies reported who is more likely to fail consistency tests. We investigated the effect of the personal characteristics and task complexity on preference inconsistency in eight different SC surveys. We found that white, higher-income and better-educated female subjects were less likely to fail consistency tests. Understanding the characteristics of subjects who are inattentive to the choice task may help in designing and pre-testing instruments that work effectively for a wider range of subjects.