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EFFICIENCY OF LINEAR EQUATING AS A FUNCTION OF THE LENGTH OF THE ANCHOR TEST
Author(s) -
BUDESCU DAVID
Publication year - 1985
Publication title -
journal of educational measurement
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.917
H-Index - 47
eISSN - 1745-3984
pISSN - 0022-0655
DOI - 10.1111/j.1745-3984.1985.tb01045.x
Subject(s) - equating , measure (data warehouse) , mathematics , statistics , monotonic function , reliability (semiconductor) , raw score , function (biology) , test (biology) , set (abstract data type) , simple (philosophy) , econometrics , computer science , raw data , mathematical analysis , data mining , paleontology , power (physics) , physics , philosophy , epistemology , quantum mechanics , evolutionary biology , biology , rasch model , programming language
One of the most widely used methods for equating multiple parallel forms of a test is to incorporate a common set of anchor items in all its operational forms. Under appropriate assumptions it is possible to derive a linear equation for converting raw scores from one operational form to the others. The present note points out that the single most important determinant of the efficiency of the equating process is the magnitude of the correlation between the anchor test and the unique components of each form. It is suggested to use some monotonic function of this correlation as a measure of the equating efficiency, and a simple model relating the relative length of the anchor test and the test reliability to this measure of efficiency is presented.