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ERIC Number: EJ894724
Record Type: Journal
Publication Date: 2010-Sep
Pages: 6
Abstractor: As Provided
Reference Count: 3
ISSN: ISSN-0013-1881
A Response to an Article Published in "Educational Research"'s Special Issue on Assessment (June 2009). What Can Be Inferred about Classification Accuracy from Classification Consistency?
Bramley, Tom
Educational Research, v52 n3 p325-330 Sep 2010
Background: A recent article published in "Educational Research" on the reliability of results in National Curriculum testing in England (Newton, "The reliability of results from national curriculum testing in England," "Educational Research" 51, no. 2: 181-212, 2009) suggested that: (1) classification accuracy can be calculated from classification consistency; and (2) classification accuracy on a single test administration is higher than classification consistency across two tests. Purpose: This article shows that it is not possible to calculate classification accuracy from classification consistency. It then shows that, given reasonable assumptions about the distribution of measurement error, the expected classification accuracy on a single test administration is higher than the expected classification consistency across two tests only in the case of a pass-fail test, but not necessarily for tests that classify test-takers into more than two categories. Main argument and conclusion: Classification accuracy is defined in terms of a "true score" specified in a psychometric model. Three things must be known or hypothesised in order to derive a value for classification accuracy: (1) a psychometric model relating observed scores to true scores; (2) the location of the cut-scores on the score scale; and (3) the distribution of true scores in the group of test-takers. (Contains 1 note, 2 tables, and 4 figures.)
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Publication Type: Journal Articles; Reports - Evaluative
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A
Identifiers - Location: United Kingdom (England)