There are many other ways in which VAS have been presented, including
vertical lines and lines with extra descriptors. Wewers & Lowe (1990) provide an
informative discussion of the bene®ts and shortcomings of different styles of
VAS.
As such an assessment is clearly highly subjective, these scales are of most
value when looking at change within individuals, and are of less value for
comparing across a group of individuals at one time point. It could be argued
that a VAS is trying to produce interval/ratio data out of subjective values that
are at best ordinal. Thus, some caution is required in handling such data. Many
researchers prefer to use a method of analysis that is based on the rank ordering
of scores rather than their exact values, to avoid reading too much into the
precise VAS score