re: st: medeff command negative percentage of total effect mediated

["Ariel Linden, DrPH" <ariel.linden@gmail.com>]

This not an unusual finding, and it is discussed in almost every paper on
mediation. I suggest you read the paper by Adam Glynn* as a starting point.
You can go from there to his reference list to learn more if that does not
suffice 

*Glynn, A.N.: The product and difference fallacies for indirect effects. Am.
J. Political Sci. 56, 257-269 (2012)

Ariel

Date: Mon, 3 Jun 2013 11:16:20 +0100
From: "worldpatient ." <worldpatient@gmail.com>
Subject: st: medeff command negative percentage of total effect mediated

Dear Statalisters,

I am using the user-written command -medeff command in Stata/IC 11 for
Windows to test for causal mediation effects.
My outcome is binary and my mediator is continuous.

My question has to do with the interpretation of the percentage and
95%CIs of total effect mediated. In my analysis, the direct and total
effects although not significant are negative while the indirect
effect is positive and very small.
As a result the percentage of the total effect mediated is negative
and the CIs range from -203 to 46..

Is there a way that I could interpret the percentage of the total
effect mediated and the CIs when this percentage is negative and the
CIs are so wide?

Many thanks,
Maria




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