RE: st: Negative binomial regression (nbreg): Plot an interaction effect of two continuous/interval variables

[jhilbe@aol.com]

I have 10 page Appendix on constructing and interpreting interactions 
for count models in my recent book,
"Negative Binomial Regression, 2nd edition" (2011, Cambridge University 
Press) and a complete 53 page chapter
on constructing, graphing, and interpreting interactions for logistic 
models in my "Logistic Regression Models"
(2009, Chapman & Hall/CRC). I use Long and Freese's methods, and 
others, for graphing.

If you would like, I'll send you a PDF of the Appendix on Interactions 
and include a separate secton from the LRM book  on constructing a 
graph for this type of interaction. All of the code for constructing 
interactions and graphics in both Stata and R  is made available in 
both books. Let me know by sending me an email at --hilbe@asu.edu-- and 
I'll get it off to you.

Joseph Hilbe

-------------------------------------------------------------------------
-------------------------------------------------------
Hilbe, Joseph M (2011), Negative Binomial Regression, 2nd edition, 
Cambridge University Press
     http://www.stata.com/bookstore/nbr.html
Hilbe, Joseph M (2009), Logistic Regression Models, Chapman & Hall/CRC
     http://www.stata.com/bookstore/lrm.html
Hardin, JW and JM Hilbe (2003), Generalized Estimating Equations, 
Chapman & Hall/CRC
     http://www.stata-press.com/books/gee.html
Hardin, JW and JM Hilbe (2007), Generalized Linear Models and 
Extensions, 2nd ed, Stata Press
     http://www.stata-press.com/books/glmext.html
Muenchen, RA and JM Hilbe (2010), R for Stata Users, Springer
      
http://www.springer.com/statistics/computanional+statistics/book/978-1-4419-1317-3
-------------------------------------------------------------------------
--------------------------------------------------------



Date: Sat, 10 Sep 2011 12:06:27 -0400
From: Cameron McIntosh <cnm100@hotmail.com>
Subject: RE: st: Negative binomial regression (nbreg): Plot an 
interaction
effect of two continuous/interval variables

Fred,

I don't know if -1SD and +1SD are always the best values to use. I 
would
recommend also trying a range of more "interesting/meaningful" values 
of your
moderator to generate predicted probabilities for plotting. You should 
also take a look at these papers:

Buis, M.L. (2010). Stata tip 87: Interpretation of interactions in 
non-linear models. The Stata Journal, 10(2), 305-308.

Norton, E.C., Wang, H., & Ai, C. (2004). Computing interaction effects 
and
standard errors in logit and probit models. The Stata Joumal, 4(2), 
154-167.http://www.unc.edu/~enorton/NortonWangAi.pdf

Ai, C., & Norton, E. C. (2003). Interaction terms in logit and probit 
models. Economic Letters, 80, 123-129.

Hayes, A.F., & Matthes, J. (2009). Computational procedures for probing
interactions in OLS and logistic regression: SPSS and SAS 
implementations.
Behavior Research Methods, 41, 
924-936.?http://www.personal.psu.edu/jxb14/M554/articles/Hayes&Matthes200
9.pdf

Francoeur, R.B. (2011). Interpreting interactions of ordinal or 
continuous
variables in moderated regression using the zero slope comparison: 
tutorial, new
extensions, and cancer symptom applications.International Journal of 
Society
Systems Science, 3(1/2), 137-158.

Cam

> Date: Sat, 10 Sep 2011 17:35:53 +0200
> Subject: st: Negative binomial regression (nbreg): Plot an 
interaction effect
of two continuous/interval variables
> From: statalistrequest@googlemail.com
> To: statalist@hsphsun2.harvard.edu
>
> Dear users of statalist,
>
> I have a nbreg model containing 3 continuous variables and one 
interaction
> effect of two of these variables.
>
> How can I get a judicious plot of the interaction effect? A common 
method
> for plotting interactions effets in general is a graph, where one uses
> predications for -SD Mean +SD of both variables.
>
> How can I do that or another valuable plot in stata for nbreg? Or how 
can I
> use prvalue to calculate the needed values to put these data somehow 
in excel?

>





*
*   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/