A01_RICH4603_04_SE_A01.QXD

(Chris Devlin) #1
isolating than many other European languages, such as French, German,
and Russian, but is also an inflecting language.

ITn
see information technology


ITA n
an abbreviation for international teaching assistant


itemn
an individual question in a test which requires the student to produce an
answer.


item analysisn
(in testing) the analysis of the responses to the items in a test in order to find
out how effective the test items are and to find out if they indicate differences
between high and low ability test takers.
see also distractor efficiency analysis, item facility, item
discrimination


item difficultyn
see item facility


item discriminationn
also d-index
(in testing) a measure of the extent to which a test item is sensitive to differ-
ences in ability among test takers. If a particular item in a test is answered
in the same way by both the test takers who do well on the test as a whole
and by those who do poorly, the item is said to have poor discrimination. In
item analysis, the item-total point-biserial correlation between the
answers to an individual item (hence “item”) and the scores on the whole test
(hence “total”) is often used as an estimate of discrimination. Or alternatively,
an item discrimination index can be calculated using the following formula:
ID =IFupper-IFlower
where ID =item discrimination for an individual item, IFupper=item facility
for the upper third (or 33%) group on the whole test, IFlower=item facility
for the lower third (or 33%) group on the whole test.
The ID index ranges from +1.00 to -1.00. In a norm-referenced test,
test items with low and negative ID indices need to be revised.


item facilityn
also difficulty index, facility, facility index, facility value, item difficulty,
p-value


item facility
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