Re: SPSS Syntax MIXED Model

Posted by Steph Bullen on
URL: http://spssx-discussion.165.s1.nabble.com/SPSS-Syntax-MIXED-Model-tp5713934p5730179.html

Hi Ryan,

Thank you very much for your wonderful inputs - I hope you are still active on this list!

Some years on from that post, I am battling with a very similar data set to Zalihe.

I have run the main effects model as per the syntax you recommended to Zalihe in this post and it works well. However, when I add the time*<predictor variables. interactions it is giving me the following warning message:

"Iteration was terminated but convergence has not been achieved. The MIXED procedure continues despite this warning. Subsequent results produced are based on the last iteration. Validity of the model fit is uncertain."

My syntax is follows:

 MIXED Weight BY Farm Group Breed WITH Age Time Baseline_Weight
  /FIXED =Farm Breed Group Age Time Baseline_Weight Farm*Time Breed*Time Group*Time | SSTYPE(3)
  /METHOD = REML
  /PRINT = G SOLUTION TESTCOV
  /RANDOM = INTERCEPT Time | SUBJECT(ID) COVTYPE(UN).

I am using SPSS 21.

My data set involves calves (ID) subjected to one of two treatments (Group) and weighed on Day 0 (Baseline_Weight), Day 42 (approx; actual days are identified under "Time) and Day 84. Breed, farm, age (at Day 0) are recorded.

Any assistance would be extremely gratefully received. You have no idea how helpful your inputs have been up until now. :)

Thank you in advance!

Steph