A context effect occurs when examinees’ item responding
behavior is affected by the location of an
item within a test. Recent advances in testing practice,
most notably adaptive testing and certain innovative
equating schemes, require items to be more invariant
across intended usages than earlier methods. In this
paper, location effects are identified as a form of multidimensionality,
and examples of testing situations
where location effects are important are described.
Then, the susceptibility to item location effects of 10
item types from the Graduate Record Examination
General Test is investigated by comparing the item
difficulty parameters of sets of items across intended
usages. Results are replicated using a second form of
the test. Two of the 10 item types, analysis of explanations
and logical diagrams, are clearly affected by
item location in the population tested. One common
item type, reading comprehension, appears to be affected
somewhat by item context in this population. It
is strongly advised that these item types not be used in
an adaptive testing program without first assessing
their susceptibility to location effects within the population
(and subpopulations) of interest.
Kingston, Neal M & Dorans, Neil J. (1984). Item location effects and their implications for IRT equating and adaptive testing. Applied Psychological Measurement, 8, 147-154. doi:10.1177/014662168400800202
Kingston, Neal M.; Dorans, Neil J..
Item location effects and their implications for IRT equating and adaptive testing.
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