"Kenneth M. Steele" wrote:
>
> > 2. When using a Likert scale with adjective-modified anchors (as in
> > "extremely pleasant" or "extremely bitter") - are we permitted to
> > compare results between subjects/groups? or are we limited to
> > within-subject comparisons?
> >
>
> This is a much trickier question as the use of the adjectives
> has caused people to be less likely to use the most extreme
> values. This would interfere with subjects assigning numbers in
> an interval-like fashion. This could have several effects
> depending upon the number of steps on your scale. Should we
> assume that this individual used these anchors with a 5-point
> scale?
This weekend I saw the practice of putting the "extreme" adjective not
at the end of the line - but about 3/4 of the way across - with the end of
the line hanging into space. This practice - so they say - makes it easier
to select "extremely."
Supposedly, it is tricky (or, downright wrong) to use these scales for
across group comparisons, they are only for within-group comparisons. The
reason is that different groups' use of the adjectives may not be
equivalent. If we compare "tasters" versus "nontasters" for instance, the
the anchor "extremely bitter" for the former may correspond to a very
intense stimulus - subjectively as intense as a very loud noises. For the
latter, an "extremely bitter" taste may be at the top of gustatory
experiences - but relatively mild relative to very loud noises. That is, the
sensory world of tasters vs. nontasters guarantees these adjectives will be
interpreted differently. The same logic would apply to other between-group
comparisons.
Interestingly, these scales are used all the time in psychology to make
between-group comparisons.
btw, while at a recent talk on tasting I discovered that I was a
"taster" - if not a borderline "supertaster."
--
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John W. Kulig [EMAIL PROTECTED]
Department of Psychology http://oz.plymouth.edu/~kulig
Plymouth State College tel: (603) 535-2468
Plymouth NH USA 03264 fax: (603) 535-2412
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"What a man often sees he does not wonder at, although he knows
not why it happens; if something occurs which he has not seen before,
he thinks it is a marvel" - Cicero.
