At 09:14 PM 5/22/00 +0800, Stephen Humphry wrote:
>It doesn't offer guidance up front exactly, no, but it provides feedback on
>whether items work, and an important (imv) conceptual framework for test
>construction. For example, if you have the Rasch model in mind, you look to
>developing items of a range of difficutly (or 'affective intensity'). You
>wouldn't necessarily think to do this if you were only using other
>techniques, yet it is surely important. Take the extreme example of a test
>in which every item is of the same affective intensity -- say for
>'satisfaction with your bank'. Everyone who is higher than a certain
>satisfaction level would be expected to agree with all items, whereas
>everyone below a certain satisfaction would be expected to disagree (of
>course, this probably won't happen but it in reality you may get something
>approaching this situation).
first, items don't have intensity ... people do in response TO an item ...
second, just because (to use an analogy) someone scores (say on a 30 item
test) high on the test does not mean that they got all items right nor,
would we expect them to ... so, just because someone has a fairly strong +
feeling towards a bank does not mean that they agree with (nor would we
expect them to) all the practices of the bank ... scale scores (not even
from a rasch developed scale) are not a true guttman scale
certainly though ... one does not need the rasch model to detect these
tendencies ...
Dennis Roberts, EdPsy, Penn State University
208 Cedar Bldg., University Park PA 16802
Email: [EMAIL PROTECTED], AC 814-863-2401, FAX 814-863-1002
WWW: http://roberts.ed.psu.edu/users/droberts/drober~1.htm
FRAMES: http://roberts.ed.psu.edu/users/droberts/drframe.htm
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