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<P><FONT SIZE=2>Thank you for your answers, Teppei.<BR>
<BR>
So, would these two models make sense?<BR>
<BR>
1) deprivation --> education level --> aging well (covariates: age, gender, region)<BR>
(with R mediation package, to study the direct and indirect effects of deprivation on aging well)<BR>
<BR>
2) education level --> economic position --> aging well (covariates: DEPRIVATION, age, gender, region)<BR>
(with R mediation package, to study the direct and indirect effecs on education on aging well, net of deprivation)<BR>
<BR>
Best,<BR>
<BR>
Angel<BR>
<BR>
-----Mensaje original-----<BR>
De: mediation-information-bounces@lists.r-forge.r-project.org en nombre de Teppei Yamamoto<BR>
Enviado el: mié 27/08/2014 15:27<BR>
Para: Mediation-information@r-forge.wu-wien.ac.at<BR>
Asunto: Re: [Mediation-information] Mediation-information Digest, Vol 25, Issue 3<BR>
<BR>
Hi Angel,<BR>
<BR>
The difference between the two estimates (multimed vs. mediation<BR>
analysis on education level as the "treatment") is that the former is<BR>
about the effect of manipulating infant deprivation on aging whereas the<BR>
latter is about the effect of manipulating education directly. That is,<BR>
they are estimating effects of different kinds of hypothetical<BR>
interventions and how they are transmitted through the variables that<BR>
are assumed to be causally descendant.<BR>
<BR>
So I think your choice boils down to what causal quantity you are trying<BR>
to estimate.<BR>
<BR>
Best,<BR>
Teppei<BR>
<BR>
<BR>
(8/27/14, 5:38 AM), Angel Rodriguez wrote:<BR>
> Thank you again, Mashhood.<BR>
><BR>
> What I do not understand yet is why we need a package like multimed if<BR>
> we can decompose a model with two causally dependent mediators (infant<BR>
> deprivation --> education level --> economic position --> aging well)<BR>
> into two models (infant deprivation --> education level --> aging well &<BR>
> education level --> economic position --> aging well).<BR>
><BR>
> Following your advise, I should include infant deprivation as a<BR>
> confounder in the model education level --> economic position --> aging<BR>
> well. But if deprivation conditions education strongly, I could end not<BR>
> finding any direct nor indirect effect of education on aging well.<BR>
><BR>
> Best regards,<BR>
><BR>
> Angel Rodriguez-Laso<BR>
><BR>
><BR>
> -----Mensaje original-----<BR>
> De: mediation-information-bounces@lists.r-forge.r-project.org en nombre<BR>
> de Mashhood Sheikh<BR>
> Enviado el: mar 26/08/2014 20:56<BR>
> Para: mediation-information@lists.r-forge.r-project.org<BR>
> Asunto: Re: [Mediation-information] Mediation-information Digest, Vol<BR>
> 25,Issue 3<BR>
><BR>
><BR>
> Hi,<BR>
><BR>
> In the model (education level --> economic position --> aging well) you<BR>
> should include all the variables that potentially confound the<BR>
> association between education level and economic position, education<BR>
> level and ageing well, and economic position and ageing well.<BR>
><BR>
> Best wishes,<BR>
> Mashhood<BR>
> ---<BR>
> Mashhood Ahmed Sheikh<BR>
> Research Fellow,<BR>
> Department of Community Medicine<BR>
> Faculty of Health,<BR>
> University of Tromsø,<BR>
> Norway<BR>
><BR>
><BR>
><BR>
><BR>
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<BR>
--<BR>
====================================<BR>
Teppei Yamamoto<BR>
Assistant Professor<BR>
Department of Political Science<BR>
Massachusetts Institute of Technology<BR>
<A HREF="http://web.mit.edu/teppei/www/">http://web.mit.edu/teppei/www/</A><BR>
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