Message/Author 

Andy Ross posted on Tuesday, April 14, 2009  1:56 pm



Dear Prof Muthen I would like to check that I am specifying my model correctly When estimating a path analysis with a nominal variable which serves as both a dependent and independent variable  do I have to create dummy variables for the part in which I treat it as an independent? ie: usevariables = u1 u2 u2a u2b u2c u3 u4; nominal = u1 u2; Model: u1#1 u1#2 u1#3 on u2a u2b u2c u3; u2#1 u2#2 u2#3 on u4; (where both u1 and u2 are 4 level nominal variables  and I have constructed 3 dummy variables u2a u2b u2c to represent u2 when treating it as a predictor) I did also try: u1#1 u1#2 u1#3 on u2#1 u2#2 u2#3 u3; u2#1 u2#2 u2#3 on u4; But I got an error message that nominal variables cannot appear on the right hand side of an on statement. Many thanks for your support Andy 


A nominal variable cannot be used as a mediator. You could look at each category separately or use the nominal variable as a grouping variable. 

Andy Ross posted on Wednesday, April 15, 2009  11:52 am



Many thanks for your response  I don't think my original question was very clear What I'm trying to do is estimate the equivalent of a latent transition analysis (example 8.13 without the interaction)  except that in my analysis c1 and c2 are not latent, and u3 and u4 are the same categorical predictor measured at two time points (in that sense I'm not examining u2 as a mediator of u4 on u1) How would I then specify the regression of u1 on u2? Many thanks Andy 


See Slides 1030 of the Topic 6 course handout at http://www.statmodel.com/newhandouts.shtml. In particular, Slide 13 shows how to make the observed variable u equivalent to the categorical latent variable c. 

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