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An Evaluation of Differential Speededness and Its Impact on the Common-Item Equating of a Reading Test

Liao, Chi-Wen
Publication Year:
Report Number:
ETS Research Memorandum
Document Type:
Page Count:
Subject/Key Words:
Speededness (Tests), Differential Speededness, Test Construction, Equating Items, Equating


The study evaluated the effect of speededness on common-item equating when the test was more speeded for one equating sample than for the other. The test studied contained 100 items. The last 20 items were in four 5-item sets, which measured different skills than the rest of the test. In each new form, the anchor included one of these 4 late-appearing item sets. This study compared the results of equating with and without this late-appearing item set in the anchor. Including this item set in the anchor affected the equating in the anticipated direction, favoring the group for which the test was less speeded. The size of this effect was not clearly related to the position of the late-appearing anchor items.

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