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Re: Asymetric Interaction - is this possible?

Posted by Bruce Weaver on Jul 23, 2014; 8:40pm
URL: http://spssx-discussion.165.s1.nabble.com/Asymetric-Interaction-is-this-possible-tp5726799p5726803.html

Tino, can you provide a substantive example where the x-y relationship is moderated by z, but the z-y relationship is not moderated by x?  Thanks.



tino wrote
Dear all,

my thought might be a bit naive, but please consider the follwing problem:

Asssume you are interested in the effect of x on y conditional on z. From a regression perspective, we would most likely use a product term in the form x*z to test this interactive relation (while also including x and z as separate predictors). However, the multiplicative approach implies that we could also use z*x, which would mean that the effect of z on y depends on x.

Although this seems straightforward from a statistical ppoint of view, from a theoretical perspective it might be important to distinguish whether x is moderated by z (Theory A) or z moderated by x (Theory B).

I am not aware of any method or approach to distinguish between such theoretical differences using a product term approach in multiple regression; are there any methodological alternatives?

Many thanks for your responses,
Tino

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Bruce Weaver
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