Discriminant validity of interval response formats: Investigating the dimensional structure of interval widths

In psychological research, respondents are usually asked to answer questions with a single response value. A useful alternative are interval responses like the dual-range slider (DRS) where respondents provide an interval with a lower and an upper bound for each item. Interval responses may be used to measure psychological constructs such as variability in the domain of personality (e.g., self-ratings), uncertainty in estimation tasks (e.g., forecasting), and ambiguity in judgments (e.g., concerning the pragmatic use of verbal quantifiers). However, it is unclear whether respondents are sensitive to the requirements of a particular task and whether interval widths actually measure the constructs of interest. To test the discriminant validity of interval widths, we conducted a study in which respondents answered 92 items belonging to seven different tasks from the domains of personality, estimation, and judgment. We investigated the dimensional structure of interval widths by fitting exploratory and confirmatory factor models while using an appropriate multivariate-logit function to transform the bounded interval responses. The estimated factorial structure closely followed the theoretically assumed structure of the tasks, which varied in their degree of similarity. We did not find a strong overarching general factor, which speaks against a response style influencing interval widths across all tasks and domains. Overall, this indicates that respondents are sensitive to the requirements of different tasks and domains when using interval response formats.