Visual analogue scale (VAS)
Short definition
The visual analogue scale is a self-report tool in which a person marks, on a line usually 10 cm long between «no pain» and «worst pain imaginable», the intensity of what they feel.
In plain language
The distance from the start of the line to the mark is measured and gives a score, usually from 0 to 100 mm. It is quick and sensitive to small changes, and is used for pain, anxiety and other symptoms. It requires some visual, motor and abstract-reasoning ability, so it can be hard for people with cognitive impairment; in those cases numeric, faces or observational scales are used.