Plotting Interaction from Zero-inflated Poisson Regression

Posted by Dale Glaser on Feb 04, 2011; 12:26am
URL: http://spssx-discussion.165.s1.nabble.com/Is-there-a-way-to-get-eigenvalues-from-CATPCA-tp3370023p3370284.html

Hi all......I have ran a multiplicative model (group x test score) using zero-inflated Poisson (ZIP) in Mplus given the DV (# of fails). The interaction term is significant for the Poisson component of the model, and now we are trying to plot the interaction  This is where I am stuck.  I couldn't find a way by which to graph this result via Mplus so I used the GENLIN option in SPSS with the log link function for the Poisson model, and thought if I saved the predicted scores I could plot the two groups x moderator interaction (as you can with OLS regression when you graph a scatterplot of the moderator and outcome and use the subgroup fit line option to super-impose the predicted lines for each group).  However, as most of you would expect when I graph the predicted scores from GENLIN against the moderator and plot the two group fit lines, it only shows the two lines since it is a perfect fit for each group.  So, does anyone have any suggestions how to overlay the predicted line for subgroups over the scatterplot based on the results from a Poisson model?   thank you very much....dale   Dale Glaser, Ph.D. Principal--Glaser Consulting Lecturer/Adjunct Faculty--SDSU/USD/Alliant Past-President, San Diego Chapter of American Statistical Association 3115 4th Avenue San Diego, CA 92103 phone: [phone] fax: [phone] email: [hidden email] website: www.glaserconsult.com