Measurement error is lower for visual analogue scales than for slider scales.

Abstract

Errors in measurement can arise in study and survey responses when there is a discrepancy between the intended and selected response. A significant portion of the scientific discourse has centered on the comparison of discrete and continuous response scales. In this study, we examined various continuous rating scales to ascertain which scale would yield the lowest measurement error. To this end, we compared visual analogue scales (VAS) with different slider scales in an online study (N = 222) that built upon the original work by Reips and Funke (2008). In this study, participants were asked to estimate where a percentage value would lie on a line ranging from 0 to 100%. The slider scale conditions differed in the initialization of the slider thumb (left, middle, right), with an additional slider condition that employed the default HTML slider with a large thumb without any modifications. The findings of this study suggest that the measurement error in estimating the true value was lower in VAS than in slider scales. Additionally, our findings suggest that VAS lead to reduced variability in errors within and between individuals. Contrary to our initial hypothesis, we did not find a higher measurement error in the default slider than in the other slider conditions. The findings of this study suggest that VAS may offer a more precise means to the assessment of ratings. Practitioners who intend to employ continuous rating scales should consider employing VAS or at least carefully consider the pitfalls of slider scales.