Compression and Conditional Effects: A Product Term Is Essential When Using Logistic Regression to Test for Interaction*. Issue 3 (26th November 2015)

• Record Type: Journal Article
• Authors: Rainey, Carlisle
• Is Part Of: Political science research and methods. Volume 4:Issue 3(2016)
• Page Start: 621
• Page End: 639
• Publication Date: 2015-11-26
• Subjects: Political science -- Periodicals; 320
• DOI: 10.1017/psrm.2015.59
• Languages: English
• ISSNs: 2049-8470

Abstract

Abstract : Previous research in political methodology argues that researchers do not need to include a product term in a logistic regression model to test for interaction if they suspect interaction due to compression alone. I disagree with this claim and offer analytical arguments and simulation evidence that when researchers incorrectly theorize interaction due to compression, models without a product term bias the researcher, sometimes heavily, toward finding interaction. However, simulation studies also show that models with a product term fit a broad range of non-interactive relationships surprisingly well, enabling analysts to remove most of the bias toward finding interaction by simply including a product term.