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Thread: Mediation regression

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    Mediation regression




    Hi all,

    I have a question regarding an analysis I just ran. I ran a mediation analysis using a bootstrap approach (requiring me to look at the confidence intervals for significance). Looking at the CI, I found that the independent variable had an indirect effect on the dependent variable through the mediator. When I looked at the individual paths, however, I noticed that the total effect (path c) was not significant. Baron and Kenny would have stopped here (this would have been step 1 for them) and not continued any further. I, however, am not using their approach. Am I safe to say that there is an indirect effect, even if the total effect was not significant because the other paths were significant and the CI did give me evidence that there was an indirect effect?

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    Re: Mediation regression

    You should provide a little more detail. More specifically, what is the p-value for the individual direct path (c). And, when you subsequently include the mediating variable what is the p-value associated with the variable for the direct variable?....it should increase.

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    Re: Mediation regression

    Quote Originally Posted by Dragan View Post
    You should provide a little more detail. More specifically, what is the p-value for the individual direct path (c). And, when you subsequently include the mediating variable what is the p-value associated with the variable for the direct variable?....it should increase.
    Below is an example of what I mean:

    IV to Mediators (a paths)
    Coeff: .1285
    se: .0176
    t: 7.2811
    p: .0000

    Direct Effects of Mediators on DV (b paths)
    Coeff: .0439
    se: .0182
    Z: 2.4108
    p: .0159
    Wald: 5.8117

    Total Effect of IV on DV (c path)
    Coeff: .0108
    se: .0132
    Z: .8195
    p: .4125
    Wald: .6715

    Direct Effect of IV on DV (c' path)
    Coeff: .0046
    se: .0136
    Z: .3344
    p: .7380
    Wald: .1119

    Bias Corrected and Accelerated Confidence Intervals
    Lower: .0012
    Upper: .0109
    Last edited by acue; 06-30-2012 at 07:20 PM.

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    Re: Mediation regression


    Interesting post, could anybody please explain in basic terms how I would test mediation of one variable between two others using regression? Is it hierarchical regression?

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