we do have a semantics problem with terms like this ... scale ... and
confuse sometimes the actual physical paper and pencil instrument with the
underlying continuum on which we are trying to place people
so, even in likert's work ... he refers to THE attitude scales ... and then
lists the items on each ... thus, it is easy to see an equating made
between the collection of items ... nicely printed ... BEING the scale ...
but really, the scale is not that ... one has to think about the SCORE
value range ... that is possible ... when this physical "thing" (nicely
printed collection of items) is administered to Ss ...
thus ... for 10 typically response worded likert items with SA to SD ...
the range of scores on the scale might be 10 to 50 ... of which any
particular S might get any one of those values somewhere along the continuum
but of course, scale is even "deeper" than that since, what we really have
is a psychophysical problem ... that is, what is the functional
relationship that links the physical scale ... 10 to 50 ... to the
(assumed to exist) underlying psychological continuum ...
PHYSICAL SCALE 10 (NEGATIVE) <--------------------------------> 50
(POSITIVE)
PSYCHOLOGICAL
CONTINUUM MOST NEGATIVE <-------------------------------->
MOST POSITIVE
problems like ... do equal distances along the physical scale ... equate to
the same and equal distances along the psychological continuum? is there a
linear relationship between these two? curvilinear?
so, i think what we really mean by scale is this construct ... ie, the
psychological continuum ... and a scale value would be where a S is along
it ... but, about the best we can do to "assess" this is to see where the S
is along the physical scale ... ie, where from 10 to 50 ... and use this as
our PROXY measure ...
BUT IN any case ... i think it is helpful NOT to call the actual instrument
... the paper and pencil collection of items ... THE scale ...
_________________________________________________________
dennis roberts, educational psychology, penn state university
208 cedar, AC 8148632401, mailto:[EMAIL PROTECTED]
http://roberts.ed.psu.edu/users/droberts/drober~1.htm
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