Open AccessMETHODS OF LINKING WITH SMALL SAMPLES IN A COMMON‐ITEM DESIGN: AN EMPIRICAL COMPARISON
Author(s) -
Kim Sooyeon,
Livingston Samuel A.
Publication year - 2009
Publication title -
ets research report series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.235
H-Index - 5
ISSN - 2330-8516
DOI - 10.1002/j.2333-8504.2009.tb02195.x
Subject(s) - equating , statistics , mathematics , resampling , econometrics , rasch model
A series of resampling studies was conducted to compare the accuracy of equating in a common‐item design using four different methods: chained equipercentile equating of smoothed distributions, chained linear equating, chained mean equating, and the circle‐arc method. Four operational test forms, each containing more than 100 items, were used for the equating, with new‐form samples of 100, 50, 25, and 10 examinees and reference‐form samples three times as large. Accuracy was assessed in terms of the root‐mean‐squared difference (over 1,000 replications) of the sample equatings from the criterion equating. Overall, chained mean equating produced the most accurate results for low scores, but the circle‐arc method produced the most accurate results, particularly in the upper half of the score distribution.