# Re: st: Basic regression interaction term question

 From John Antonakis <[email protected]> To [email protected] Subject Re: st: Basic regression interaction term question Date Fri, 10 Oct 2008 20:24:03 +0200

Yes. What's important is the coefficient of the AB term. The test A B AB is simply the F-test that the coefficients are simultaneously different from zero. If you care about interaction, AB is what is important, regardless of the significance of B or A or A B or A B AB..
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Here is an interesting paper about this question: Bedeian, A. G., and Mossholder, K. W. Simple Question, Not so Simple Answer: Interpreting Interaction Terms in Moderated Multiple Regression. Journal of Management, 1994, 20, 159-165 (get it here: http://www.bus.lsu.edu/management/faculty/abedeian/articles/SimpleQues-JOM1994.pdf ).
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Best,
J.

____________________________________________________

Prof. John Antonakis
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Associate Dean Faculty of Business and Economics
```University of Lausanne
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Michael I. Lichter wrote:
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This is a pretty basic question, but I haven't been able to find any examples in the lit with this particular configuration ...
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Suppose you regress Y on A and B, and you expect an interaction between A and B.
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In the regression Y = A + B, the coefficient for B is not significant, but you have reason to think that it will be significant once you introduce the interaction term.
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However, in the regression Y = A + B + AB, the coefficient for B remains non-significant even though the coefficient for AB is significant. Yet, "test A B AB" is significant.
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Is it reasonable to treat this as a significant interaction?

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What if AB is not significant either but "test A B AB" is still significant?
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Michael
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