How does a visual analogue scale measure pain?

The visual analogue scale (VAS) measures pain intensity by allowing individuals to mark their level of pain on a continuous line or segmented ruler. This tool typically features endpoints that represent the extremes of pain, such as "no pain" and "worst pain imaginable." When a person indicates their level of pain by marking on the scale, it provides a visual representation of pain intensity, which can be quantified for assessment and treatment decisions.

This method is particularly effective because it captures a range of pain experiences rather than limiting responses to binary options, as some scales do. It also avoids the potential vagueness or interpretive variance in verbal descriptors and physiological evaluations, which can differ greatly among individuals due to subjective experiences of pain. Using a segmented ruler emphasizes the continuum of pain perception and allows healthcare professionals to better assess and track pain levels over time.