Hi Weichao-<div><br></div><div>If you review the formula for proportion mediated that is in our Psychological Methods paper, this sort of thing can happen when your indirect and direct effects go in different directions, as they do in your case.</div>
<div><br></div><div>best,</div><div>Dustin</div><div><br clear="all">Dustin Tingley<br>Government Department<br>Harvard University<br><a href="http://scholar.harvard.edu/dtingley" target="_blank">http://scholar.harvard.edu/dtingley</a><br>
<br>
<br><br><div class="gmail_quote">On Thu, Sep 15, 2011 at 10:55 AM, Weichao Bao <span dir="ltr"><<a href="mailto:weichaobao@gmail.com">weichaobao@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<p class="MsoNormal">Dear All,</p><p class="MsoNormal"><br></p><p class="MsoNormal">I am using the mediation package on my research. The outcome is dichotomous and the treatment is continuous. It was run with GAM model. But I am confused with the following results. It shows all the Mediation Effect_0, Mediation Effect_1,and Mediation Effect (Average) have significant mediation effect based on 95% CI. However, the Proportion of Total Effect via Mediation_0, Proportion of Total Effect via Mediation_1, and Proportion of Total Effect via Mediation (Average) indicate there is no mediation at all based on the 95% confidence interval. The result is: </p>
<p class="MsoNormal"><br></p><p class="MsoNormal">Mediation Effect_0:<span> <font color="#000099">
</font></span><font color="#000099">-0.004309 95 % CI<span> </span>-0.0086640
-0.0007235 </font></p>
<p class="MsoNormal">Mediation Effect_1:<span>
</span><font color="#000099">-0.006557 95 % CI<span> </span>-0.014173
-0.001015 </font></p>
<p class="MsoNormal">Direct Effect_0:<span>
</span>0.04452 95 % CI<span> </span>0.001001 0.112969
</p>
<p class="MsoNormal">Direct Effect_1:<span>
</span>0.04228 95 % CI<span> </span>0.0009312
0.1061973 </p>
<p class="MsoNormal">Total Effect:<span> </span>0.03797
95 % CI<span> </span>-0.004335<span> </span>0.101359 </p>
<p class="MsoNormal">Proportion of Total Effect via Mediation_0:<span> <font color="#ff0000"> </font></span><font color="#ff0000">-0.1069 95 % CI -1.592
0.817 </font></p>
<p class="MsoNormal">Proportion of Total Effect via Mediation_1:<span> <font color="#cc0000"> </font></span><font color="#cc0000">-0.1701 95 % CI<span> </span>-1.8595<span>
</span>0.8059 </font></p>
<p class="MsoNormal">Mediation Effect (Average):<span>
</span><font color="#000099">-0.005433 95 % CI<span> </span>-0.011059
-0.000928 </font></p>
<p class="MsoNormal">Direct Effect (Average):<span>
</span>0.0434 95 % CI<span> </span>0.0009659
0.1098405 </p>
<p class="MsoNormal">Proportion of Total Effect via Mediation (Average):<span> </span><font color="#990000">-0.1391 95 % CI -1.7258
0.8114 </font></p><p class="MsoNormal"><font color="#990000"><br></font></p><p class="MsoNormal"><font color="#990000"><span style="color:rgb(0, 0, 0)">Can somebody help me to explain this?</span></font></p>
<p class="MsoNormal"><font color="#990000"><span style="color:rgb(0, 0, 0)"><br></span></font></p><p class="MsoNormal">Thanks a lot.</p><p class="MsoNormal">Sincerely,</p><p class="MsoNormal"><br>
</p><font color="#888888"><p class="MsoNormal">Weichao</p><p class="MsoNormal"><font color="#990000"><br></font></p>
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