Validity Test

One of the eight choice questions was included in the survey instrument to internally test the validity of each respondent’s choices. Specifically, this question asked respondents to choose between two trials where one trial provided more monetary compensation and fewer procedures and all other attributes were the same. This “logic test” allowed us to determine whether an individual respondent sufficiently understood the choice questions, so they could indicate a preference for a clearly better trial, a concept known as “dominance” in the conjoint analysis literature.