visueelanaloge

Visueel-analoge schaal (VAS), in English Visual Analog Scale, is a psychometric instrument used to measure subjective experiences that cannot be directly quantified, such as pain, fatigue, nausea or mood. It typically consists of a straight line, commonly 10 centimeters long, with endpoints that represent extremes of the phenomenon (for example, “no pain” and “worst imaginable pain”). Respondents mark a point on the line that corresponds to their current state. The score is derived by measuring the distance from the low end to the mark, usually in millimeters, yielding a 0–100 scale.

Administration can be paper-based or digital. Clear instructions and consistent anchors are essential to ensure reliability. The VAS is unidimensional, allowing fine-grained measurement and sensitivity to small changes over time. It is versatile and widely used in clinical practice and research for both acute and chronic conditions.

Advantages include its simplicity, speed, and the ability to produce continuous data with high sensitivity to change. It can be applied across diverse populations and domains, and digital versions can streamline data capture and analysis.

Limitations include the assumption of a linear perception of intensity, which may not hold for every individual. Some patients may struggle with understanding the anchors, using the line due to cognitive or motor limitations, or language barriers. Comparability across studies can be affected by different anchor definitions or line lengths, and ceiling or floor effects can occur in certain contexts.

Variants include shorter 0–10 scales and vertically oriented versions, as well as digital sliders. Numerous translations and validated versions exist, including Dutch, to support cross-cultural use.