<div dir="ltr">Dear John,<div><br></div><div> yes, we have updated the software significantly since 2010 and now it should incorporate the ordered mediator and outcome models. The package can also handle weights when fitting each of the models. </div><div><br></div><div>Best,</div><div>Kosuke</div><div><br></div></div><div class="gmail_extra"><br clear="all"><div><div dir="ltr"><div>Kosuke Imai</div><div>Department of Politics<br></div><div>Princeton University</div><div><a href="http://imai.princeton.edu" target="_blank">http://imai.princeton.edu</a></div></div></div>
<br><div class="gmail_quote">On Sun, Oct 12, 2014 at 9:36 AM, Evans, John <span dir="ltr"><<a href="mailto:jhevans@ucsd.edu" target="_blank">jhevans@ucsd.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Dear Kosuke,<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Thanks for your quick response. I would like to ask a follow up question please. I am looking at your paper called “causal mediation analysis using R” which
is Chapter 8 of a book. Table 8.1 on page 137 says that the R version can handle an ordered mediator, but not an ordered outcome. Moreover, if the mediator is ordered, the outcome must be treated as continuous. But, in your forthcoming paper in the Journal
of Statistical Software it says in Table 1 on page that the program can handled ordered mediator when matched with an ordered outcome. If I am reading that right, can I presume you and your colleagues have improved the R version between 2010 and now?<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Before I read these papers on R more carefully, one final question: can the R package (of which I know nothing) handle population weights? If not, that might
be reason to stick to Stata, despite having to either use binary or continuous models.
<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Thanks for your help.<u></u><u></u></span></p><span class="">
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">John<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">John H. Evans<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Professor of Sociology<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">University of California, San Diego<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><a href="http://sociology.ucsd.edu/faculty/JohnHEvans.shtml" target="_blank"><span style="color:#0563c1">http://sociology.ucsd.edu/faculty/JohnHEvans.shtml</span></a><u></u><u></u></span></p>
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</span><p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""> Kosuke Imai [mailto:<a href="mailto:kimai@Princeton.Edu" target="_blank">kimai@Princeton.Edu</a>]
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<b>Sent:</b> Saturday, October 11, 2014 8:12 AM<br>
<b>To:</b> Evans, John<br>
<b>Subject:</b> Re: Question about mediate<u></u><u></u></span></p><div><div class="h5">
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<p class="MsoNormal">Dear John,<u></u><u></u></p>
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<p class="MsoNormal"> Thanks for your email and interests in my work. Unfortunately, there is no immediate plan to extend the Stata software. However, we have been working on the development of our R package and we made it easy even for non-R users. And
so, I encourage you to use the R package if that is possible. Otherwise, I think you have to go with a binary model or a linear model, neither of which is optimal but may still give you estimates that are close to what you get with more appropriate modeling
strategies. <u></u><u></u></p>
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<p class="MsoNormal">Best,<u></u><u></u></p>
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<p class="MsoNormal">Kosuke<u></u><u></u></p>
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<p class="MsoNormal">---------------------------------------------------------<br>
Kosuke Imai Office: Corwin Hall 036<br>
Professor Phone: <a href="tel:609-258-6601" value="+16092586601" target="_blank">609-258-6601</a><br>
Department of Politics Fax: <a href="tel:609-258-1110" value="+16092581110" target="_blank">609-258-1110</a><br>
Princeton University Email: <a href="mailto:kimai@Princeton.Edu" target="_blank">kimai@Princeton.Edu</a><br>
Princeton, NJ 08544-1012 <a href="http://imai.princeton.edu" target="_blank">http://imai.princeton.edu</a><br>
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<p class="MsoNormal">On Sat, Oct 11, 2014 at 10:00 AM, Evans, John <<a href="mailto:jhevans@ucsd.edu" target="_blank">jhevans@ucsd.edu</a>> wrote:<u></u><u></u></p>
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<p class="MsoNormal">Dear Professor Imai,<u></u><u></u></p>
<p class="MsoNormal">I have not made claims in my career so far that require mediation models. However, I now realize that I might have to do so for a project I am working on. I read your co-authored
2010 paper (in Psychological Methods) and the 2011 paper (in APSR) with interest. I use Stata.<u></u><u></u></p>
<p class="MsoNormal"> <u></u><u></u></p>
<p class="MsoNormal">All of the critical variables I would be using (X, M, Y) are ordered categorical, typically with 4 to 7 categories, from public opinion data, that need to have population weights.
In the APSR paper you imply that your method could be used in an ordered logistic (or ordered probit) environment. But, the Stata program “mediate” only accepts linear and logistic models. Do you know if there are any plans underway to expand this program
to ordered logistic models? Is there an alternative? My back up plan if I go the mediation route would be to dichotomize all of these variables, but that would be throwing away a lot of information.<u></u><u></u></p>
<p class="MsoNormal"> <u></u><u></u></p>
<p class="MsoNormal">Thank you for any advice you may have.<u></u><u></u></p>
<p class="MsoNormal"> <u></u><u></u></p>
<p class="MsoNormal">Best wishes,<u></u><u></u></p>
<p class="MsoNormal">John<u></u><u></u></p>
<p class="MsoNormal"> <u></u><u></u></p>
<p class="MsoNormal">John H. Evans<u></u><u></u></p>
<p class="MsoNormal">Professor of Sociology<u></u><u></u></p>
<p class="MsoNormal">University of California, San Diego<u></u><u></u></p>
<p class="MsoNormal"><a href="http://sociology.ucsd.edu/faculty/JohnHEvans.shtml" target="_blank">http://sociology.ucsd.edu/faculty/JohnHEvans.shtml</a><u></u><u></u></p>
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