Being Careful with Conjoints: Accounting for Inattentiveness in Conjoint Experiments

In typical survey experiments--i.e., experiments involving a limited amount of manipulated content--respondent inattentiveness tends to bias treatment effect estimates toward zero. This same bias likely exists in conjoint experiments, which require respondents to attend to an even larger amount of manipulated content. Yet, little research has investigated strategies to account for inattentiveness in conjoint experiments specifically. In this study, we explore ways to both measure--and account for--inattentiveness when estimating causal effects in single- and two-profile conjoint designs. Replicating published conjoint experiments with large national samples, our study offers researchers a simple strategy that relies upon pre-treatment measures of attentiveness. Further, we propose a novel method--``conjoint attention checks'' (CACs)-- to both measure respondents' attentiveness to conjoint profiles and provide for more robust tests of hypotheses in conjoint experiments. Lastly, we provide researchers with importable survey templates to facilitate the use of CACs in their own experiments.