Use of visual analog scales in economic evaluation.

Visual analog scales or rating scales are commonly used in economic evaluation to elicit preferences in order to estimate quality-adjusted life years. Values obtained from visual analog scales have been used on their own or via a transformation to map them onto one of the choice-based methods for elicting preferences, namely standard gamble or time trade-off. The arguments against using visual analog scales in economic evaluation directly or indirectly via a transformation are reviewed. It is concluded that it canonly ever provide a second best solution compared with the direct use of a choice-based technique.