Published on *OpenMx* (http://openmx.psyc.virginia.edu)

By *nbarclay*

Created *03/31/2011 - 04:18*

Thu, 03/31/2011 - 04:18 — nbarclay [1]

I am running models of GxE where I have age as a continuous moderator of a continuous phenotype. I have initially run the standard linear GxE model as outlined by Purcell (2002). However, I had problems getting this to fit. Out of interest, I ran the non-linear script, and this was successful. In addition to running the full model I have run nested models where the influence of the moderating terms are successively dropped. I am just wondering whether it is logically implausible to run a model where I retain quadratic paths (for the non-linear interaction), but drop the linear ones? The best fitting model appears to be one where only the quadratic moderation of E is retained and all other moderating paths (i.e. linear A, C, E, quadratic A and C) are dropped.

Any advice would be much appreciated! Thanks!

**Links:**

[1] http://openmx.psyc.virginia.edu/users/nbarclay

[2] http://openmx.psyc.virginia.edu/thread/857

[3] http://openmx.psyc.virginia.edu/thread/851

[4] http://openmx.psyc.virginia.edu/forums/opensem-forums/behavioral-genetics-models