APA Dictionary of Psychology

a psychometric instrument used to evaluate subjective characteristics that extend over a range of continuous values. Respondents specify their level of the characteristic of interest by indicating a position along a continuous line, anchored at its end points by word descriptors. For example, a visual analogue scale for performance might have poor on the left end with a blank line across to excellent on the right end. The respondent would mark a place along that line to indicate their perceived performance level. Also called unnumbered graphic rating scale.