Investigation of an odor intensity evaluation:

The conventional six-point odor intensity scale has been treated as one of the standard scales to evaluate perceived odor intensity. However, as an ordinal scale, it has an arithmetical limitation in statistical analysis. Therefore, a new rating method was introduced. It has a horizontal line with six-point scales labeled with the six odor intensity descriptors as in the visual analogue scale (VAS). Here, evaluators can draw a diagonal short line at any position on the horizontal line regardless of the position of the six-point scales, and thus it can theoretically be regarded as an interval scale. However, there is a concern that the language labels affect an evaluation in such a method. Therefore, we compared the odor intensity ratings evaluated by the labeled- and non-labeled VASs in one experimental framework. The results indicate that both labeled- and non-labeled-VASs can be used to rate perceived odor intensity with a statistical advantage as an interval scale.