Order of fitting fixed effects

From: Clempson, Andrew Martin <aclempson_at_RVC.AC.UK>
Date: Mon, 27 Jul 2009 16:22:25 +0100

Dear All,


I am looking for some advice on determining the order in which fixed
effects should be fitted in an animal model.


I am currently carrying out association studies between SNPs and growth
in cows. My fixed effects include herd-year-season (HYS), covariate of
Age, and the SNP, and a random effect of 'Animal'. The model is
currently arranged in the following order -


Height ~ mu HYS Age SNP !r ANIMAL



I have found that if I change the order in which the fixed effects are
fitted, the results differ. After checking various papers, it appears
that some have fitted the SNP first, whereas others fit the SNP at the


I would be very grateful for any clarification,

Kind Regards


Received on Tue Jul 27 2009 - 16:22:25 EST

This webpage is part of the ASReml-l discussion list archives 2004-2010. More information on ASReml can be found at the VSN website. This discussion list is now deprecated - please use the VSN forum for discussion on ASReml. (These online archives were generated using the hypermail package.)