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Re: st: SimpleSlopes in Multilevel Models


From   Stas Kolenikov <skolenik@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: SimpleSlopes in Multilevel Models
Date   Sun, 5 Feb 2012 15:55:33 -0500

If -zpos- is a binary variable with values 0/1, then the relation for
low levels is given by the coefficient itself, and for high levels, by

lincom _b[ ZSchaufelishort ] + _b[ EExPOS ]

which would invoke the covariance matrix behind the scenes. This can
also be done with -margins-, and the corresponding plots, with
-marginsplot-.

On Sun, Feb 5, 2012 at 2:03 PM, Kerstin Alfes <KAlfes@gmx.de> wrote:
> Thanks for the references, Cam. I will look into them!
>
> Stan, I would like to graph the interaction and also calculate whether the relationship between ZSchaufelishort and logperformance is significant for high and/or low levels of ZPOS. If there is a way to do this without the ACM, that would help a lot.
>
> Best wishes
> Kerstin
>
>
> -------- Original-Nachricht --------
>> Datum: Sun, 5 Feb 2012 10:21:14 -0500
>> Von: Stas Kolenikov <skolenik@gmail.com>
>> An: statalist@hsphsun2.harvard.edu
>> Betreff: Re: st: SimpleSlopes in Multilevel Models
>
>> On Sun, Feb 5, 2012 at 9:31 AM, Cameron McIntosh <cnm100@hotmail.com>
>> wrote:
>> > If you want to dissect the interaction effects further, yes you would
>> need to estimate and test simple slopes, for which you would need the
>> covariance between the main effect and interaction coefficients as you say. I
>> don't know how to request the ACM in Stata, but tech support should be able to
>> help you.
>>
>> I am pretty sure one won't need to try to get the covariance matrices
>> (which are available as -e(V)-), as there is little you cannot do
>> between -test-, -testnl-, -lincom- and -nlcom-. Matrix code will be
>> ugly, and you need to master the convenience tools, anyway. What is
>> involved in "estimating and testing simple slopes"?
>>
>> --
>> Stas Kolenikov, also found at http://stas.kolenikov.name
>> Small print: I use this email account for mailing lists only.
>>
>> *
>> *   For searches and help try:
>> *   http://www.stata.com/help.cgi?search
>> *   http://www.stata.com/support/statalist/faq
>> *   http://www.ats.ucla.edu/stat/stata/
>
> --
> Kerstin Alfes
>
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-- 
Stas Kolenikov, also found at http://stas.kolenikov.name
Small print: I use this email account for mailing lists only.

*
*   For searches and help try:
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*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/


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