A critical review of visual analogue scales in the measurement of clinical phenomena.

Visual analogue scales (VAS) have been used in the social and behavioral sciences to measure a variety of subjective phenomena. The VAS method has potential utility for the measurement of a variety of clinical phenomena of interest to nurse investigators. In this review a description of the various forms of the VAS and an historical overview of their development are presented. In addition, conceptual, psychometric, and statistical aspects of the VAS are considered. Finally, strengths and limitations of the VAS method are addressed.