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An Alternative Data Collection Design for Equating With Very Small Samples NEAT SiGNET

Author(s):
Puhan, Gautam; Moses, Tim P.; Grant, Mary C.; McHale, Frederick J.
Publication Year:
2008
Report Number:
RR-08-11
Source:
ETS Research Report
Document Type:
Report
Page Count:
35
Subject/Key Words:
Equating, Non-Equivalent-Groups Anchor Test (NEAT) Design, Single-Group Equating with Nearly Equivalent Test Forms (SiGNET) Design, Error, Bias, Testlets

Abstract

As evident, there are at least two merits of the SiGNET design over the nonequivalent groups with anchor test (NEAT) design. First, it facilitates the use of an SG equating design, which has the least random equating error, and second, it allows for the accumulation of sufficient data to equate the second form. Since the examinees scores are based only on the first form, (i.e., the operational form), the two forms can be administered until sufficient data are collected to equate the second form. This study compared equatings under the SiGNET and NEAT designs and found reduced bias and error for the SiGNET design in very small sample size situations (e.g., N = 10 or 15). Implications for practice using the SiGNET design are also discussed.

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