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ERIC Number: EJ859867
Record Type: Journal
Publication Date: 2009-Sep
Pages: 17
Abstractor: As Provided
Reference Count: 91
ISBN: N/A
ISSN: ISSN-1082-989X
Subject-Centered Scalability: The Sine Qua Non of Summated Ratings
Drewes, Donald W.
Psychological Methods, v14 n3 p258-274 Sep 2009
A unifying theory of subject-centered scalability is offered that is grounded in structural true score modeling, is conceptually distinct from internal consistency and homogeneity as determined by item correlations, and is empirically confirmable. Scalability holds when item true scores are perfectly correlated but differ in their individual scale metric. The condition of scalability imposes constraints that allow individual item reliability to be estimated independently of scalability. Scalability is shown to imply unit rank and to be testable by a single-factor confirmatory factor analysis reinterpreted as a test of unit rank. High item correlations are shown, contrary to intuition, to be an insufficient condition for scalability. Conversely, low item correlations do not necessarily imply lack of scalability. A stepped decision-oriented procedure is offered as a guideline in summated rating scale construction. (Contains 2 tables.)
American Psychological Association. Journals Department, 750 First Street NE, Washington, DC 20002-4242. Tel: 800-374-2721; Tel: 202-336-5510; Fax: 202-336-5502; e-mail: order@apa.org; Web site: http://www.apa.org/publications
Publication Type: Journal Articles; Reports - Research
Education Level: Higher Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A