Part-Whole Correlations and Test Reliability

Author(s):

Tucker, Ledyard R

Publication Year:

1951

Report Number:

RM-51-13

Source:

ETS Research Memorandum

Document Type:

Report

Page Count:

4

Subject/Key Words:

Equated Scores, Test Reliability

Abstract

A table is presented here giving the part-whole correlations to be expected for selected test reliabilities and relative sizes of the part. Two uses for such a table are also given: 1) to decide how many items to use in a common subtest in order to equate two forms of a test; and 2) to estimate the reliability of a test after the test has been given and the part-whole correlation is known. The theoretical derivation of the part-whole correlation is also discussed briefly.

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