I need to compare between NLMIXED and MIXED, and I am not sure if I can use AIC, BIC, or just look the residuals, or even fit the linear model on the NLMIXED. I would appreciate any thoughts you may have.
Thank you
Marcio
NLMIXED does maximum likelihood only (ML). MIXED does REML as the default; you can't compare likelihoods or AIC, etc., between ML and REML. So if you want to compare the output of the two procedures, you must use METHOD=ML statement option in MIXED.
Also, you should use TECH=NRRIDG for the optimization technique in NLMIXED in order to match the optimization method used in MIXED.
You can fit linear models in NLMIXED, and with proper definition, get information criteria that exactly match.
The hard part of what you are asking comes down to making sure that your optimization methods are the same, fixed effects similarly defined, and DV measures are the same. What do you have in mind to compare between the two methods?
Steve Denham
NLMIXED does maximum likelihood only (ML). MIXED does REML as the default; you can't compare likelihoods or AIC, etc., between ML and REML. So if you want to compare the output of the two procedures, you must use METHOD=ML statement option in MIXED.
Also, you should use TECH=NRRIDG for the optimization technique in NLMIXED in order to match the optimization method used in MIXED.
Don't miss out on SAS Innovate - Register now for the FREE Livestream!
Can't make it to Vegas? No problem! Watch our general sessions LIVE or on-demand starting April 17th. Hear from SAS execs, best-selling author Adam Grant, Hot Ones host Sean Evans, top tech journalist Kara Swisher, AI expert Cassie Kozyrkov, and the mind-blowing dance crew iLuminate! Plus, get access to over 20 breakout sessions.
ANOVA, or Analysis Of Variance, is used to compare the averages or means of two or more populations to better understand how they differ. Watch this tutorial for more.
Find more tutorials on the SAS Users YouTube channel.