On Sat, Jun 6, 2009 at 12:03 PM, Jeroen Ooms<jeroenooms at gmail.com> wrote:
For my GUI, I would like the user to be able to compare a fixed effects
model with a random effects model. For example:
fm0 <- lmer(Reaction ~ Days, sleepstudy);
fm1 <- lmer(Reaction ~ Days + (1|Subject), sleepstudy);
anova(fm0,fm1);
However, this returns the obvious "No random effects terms specified in
formula" error for the first model. I've also tried fitting the fixed
effects model with lm:
fm0 <- lm(Reaction ~ Days, sleepstudy);
fm1 <- lmer(Reaction ~ Days + (1|Subject), sleepstudy);
anova(fm0,fm1);
Try listing them the other way around
anova(fm1, fm0)
If the first model in the call to anova is of class "lm" then the
method for that class is the one chosen and that method doesn't know
about models created by lmer. You must list them so that the lmer
model comes first.