Stated preference practitioners are increasingly relying on internet panels to gather data, but emerging evidence suggests potential limitations with respect to respondent and response quality in such panels. We identify groups of inattentive respondents who have failed to watch information videos provided in the survey to completion. Our results show that inattentive respondents have a higher cost sensitivity, are more likely to have a small scale parameter, and are more likely to ignore the non-cost attributes. These results are largely driven by respondents failing to watch the information video about the discrete choice experiment, attributes and levels, which underlines the importance of information provision and highlights possible implications of inattentiveness. We develop a modeling framework to simultaneously address preference, scale and attribute processing heterogeneity. We find that when we consider attribute non-attendance—scale differences disappear, which suggests that the type of heterogeneity detected in a model could be the result of un-modeled heterogeneity of a different kind. We discuss implications of our results.