Being Careful with Conjoints: Accounting for Inattentiveness in Conjoint Experiments

In typical survey experiments–i.e., experiments that involve a relatively limited amount of manipulated content–respondent inattentiveness tends to biase treatment effect estimates toward zero. Such bias may be even more pronounced in conjoint experiments, which require respondents to attend to an even larger amount of manipulated content. And yet, little research has investigated strategies of accounting for inattentiveness in conjoint experiments specifically. In this study, we explore potential ways to both measure–and account for–respondent inattentiveness when estimating causal effects in both single- and two-profile conjoint experiments. Replicating published conjoint experiments with large national samples, we demonstrate how researchers can implement a simple strategy using pre-treatment measures of attentiveness. Toward this end, 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.