ERIC Number: EJ766180
Record Type: Journal
Publication Date: 2007-Jun
Pages: 18
Abstractor: Author
ISBN: N/A
ISSN: ISSN-1082-989X
EISSN: N/A
Centering Predictor Variables in Cross-Sectional Multilevel Models: A New Look at an Old Issue
Enders, Craig K.; Tofighi, Davood
Psychological Methods, v12 n2 p121-138 Jun 2007
Appropriately centering Level 1 predictors is vital to the interpretation of intercept and slope parameters in multilevel models (MLMs). The issue of centering has been discussed in the literature, but it is still widely misunderstood. The purpose of this article is to provide a detailed overview of grand mean centering and group mean centering in the context of 2-level MLMs. The authors begin with a basic overview of centering and explore the differences between grand and group mean centering in the context of some prototypical research questions. Empirical analyses of artificial data sets are used to illustrate key points throughout. The article provides a number of practical recommendations designed to facilitate centering decisions in MLM applications.
Descriptors: Predictor Variables, Item Response Theory, Statistical Analysis, Research, Data Interpretation, Case Studies
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 - Descriptive
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A
Grant or Contract Numbers: N/A
IES Cited: ED561144