"I would suggest rethinking your reliance on Rasch fit
statistics as a criterion for item rejection .... In many cases,
the best (most highly discriminating) items would be rejected if
one relied on Winsteps' Infit and Outfit statistics."
NCME reviewer, as reported by Ryan Bowles
Conventional wisdom says "When items correlate highly with one
another, those with the highest average correlations are the best
items" (Jm Nunnally, Psychometric Theory, 1967, p. 261).
But it is well-established that there can be too much of a good
thing ... inter-item correlations can become too high.
"Other things being equal, interdependent items tend to decrease the reliability of a test. ... For the tendency becomes to answer [correctly] neither item or both items and thereby produces an effect equivalent to reducing the number of items in a test." (Percival M. Symonds, "Factors influencing test reliability", Journal of Educational Psychology, 1928, 19, 73-87. Italics his.)
"The development of common constructs can also contribute to a
cohesive knowledge core and further enhance theoretical
understanding."
Michael J. Feuer, Lisa Towne, and Richard J. Shavelson (2002)
Scientific Culture and Educational Research. Educational
Researcher, 31, 8, 11
The growth of Rasch publications in medical literature according to Medline. Its logistic shape (predicted by the bibliographic analyses of Derek de Solla Price) suggests a ceiling of 500 articles per year, at which point Rasch will be regarded as routine. Courtesy of William Fisher. |
RMT 16:3 Quotations and Notations. 16:3 p.884ff.
RMT 16:3 Quotations and Notations. Rasch Measurement Transactions, 2002, 16:3 p.884ff.
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