Capturing Richer Information -- On Establishing the Validity of an Interval-Valued Survey Response Mode

TL;DR

This paper introduces an interval-valued survey response mode using a continuous scale, demonstrating its effectiveness in capturing richer information and reflecting respondent uncertainty, validated through empirical study with positive participant feedback.

Contribution

It proposes a novel interval-valued response method for surveys and provides initial empirical validation of its effectiveness and interpretability compared to traditional formats.

Findings

Respondents effectively used interval widths to express uncertainty.

Interval responses reflected experimental manipulations accurately.

Participants showed overconfidence with disjunctive intervals, but well-calibrated responses for conjunctive intervals.

Abstract

Obtaining quantitative survey responses that are both accurate and informative is crucial to a wide range of fields. Traditional and ubiquitous response formats such as Likert and Visual Analogue Scales require condensation of responses into discrete point values - but sometimes a range of options may better represent the correct answer. In this paper, we propose an efficient interval-valued response mode, whereby responses are made by marking an ellipse along a continuous scale. We discuss its potential to capture and quantify valuable information that would be lost using conventional approaches, while preserving a high degree of response-efficiency. The information captured by the response interval may represent a possible response range - i.e., a conjunctive set, such as the real numbers between three and six. Alternatively, it may reflect uncertainty in respect to a distinct response - i.e., a disjunctive set, such as a confidence interval. We then report a validation study, utilizing our recently introduced open-source software (DECSYS) to explore how interval-valued survey responses reflect experimental manipulations of several factors hypothesised to influence interval width, across multiple contexts. Results consistently indicate that respondents used interval widths effectively, and subjective participant feedback was also positive. We present this as initial empirical evidence for the efficacy and value of interval-valued response capture. Interestingly, our results also provide insight into respondents' reasoning about the different aforementioned types of intervals - we replicate a tendency towards overconfidence for those representing epistemic uncertainty (i.e., disjunctive sets), but find intervals representing inherent range (i.e., conjunctive sets) to be well-calibrated.