Description

Visual Analogue Scales (VAS) are measurement tools used to assess the intensity or frequency of a phenomenon, often of a subjective nature, such as pain, anxiety, or satisfaction. A VAS typically consists of a continuous line, usually 10 centimeters long, on which participants place a mark to indicate their position between two endpoints representing the limits of the measurement.

Objective

The main objectives of Visual Analogue Scales are:
Subjective assessment: They allow individuals to accurately and sensitively express their subjective experiences, such as pain or stress.
Quantification of emotions: They convert qualitative assessments into quantitative data, facilitating analysis and comparison.
Ease of use: They offer a simple, user-friendly tool that requires minimal training to implement.

Analysis

Using VAS involves the following stages:
Design of the scale:
A 10-centimeter line with endpoints defining the measurement limits (e.g., “no pain” to “unbearable pain”).
Instructions for participants:
Participants are asked to place a mark along the line to indicate the intensity or frequency of their experience.
Data collection:
Measurements are converted into numerical values by measuring the distance from the left end of the line to the participant’s mark, typically in millimeters (0–100).
Analysis:
The data can be used for statistical analysis of subjective ratings, allowing comparisons between groups or conditions.

Scoring

VAS scoring is continuous and allows for the quantification of subjective experiences with high sensitivity:
0: Represents the absence of the characteristic (e.g., no pain).
100: Represents the maximum intensity of the characteristic (e.g., unbearable pain).
The precision of the measurement allows for detailed comparisons between individual ratings and changes over time.

References

Aitken, R. C. (1969). Measurement of Feelings Using Visual Analogue Scales. Proceedings of the Royal Society of Medicine, 62(10), 989–993.
McCormack, H. M., Horne, D. J., & Sheather, S. (1988). Clinical Applications of Visual Analogue Scales: A Critical Review. Psychological Medicine, 18(4), 1007–1019.
Gift, A. G. (1989). Visual Analogue Scales: Measurement of Subjective Phenomena. Nursing Research, 38(5), 286–288.