Syntax equivalence r vs spss

Question

I built a model in r with the lmer function:

lmer(DV ~ IV1 + IV1:IV2 - 1 + (1|Group/Participant)

This was correctly specified and I got the results I expected.

I'm now trying to replicate these results in spss. so far I have:

MIXED   DV BY IV1 IV2
   /FIXED IV1 IV1*IV2  | NOINT SSTYPE(3)
   /METHOD   REML
   /RANDOM= INTERCEPT | SUBJECT(Group*Participant) COVTYPE(VC)
   /PRINT= SOLUTION  TESTCOV.

My results are not remotely similar, and I believe it is because of the differences between the : and * terms.

How can I replicate IV1 + IV1:IV2 in SPSS?

`(1|Group/Participant)` includes *two* random-effect terms, one for group and one for the interaction of group and participant. I don't know how to specify that in SPSS, but it doesn't look like what you've done. — Ben Bolker, Sep 16 '20 at 02:20
@BenBolker Thank you for your response! My current understanding is that since participants are nested within groups, they should be treated as fixed effects. If this is the case, how might I run such a model in lmer under the above framework? — r_user, Sep 17 '20 at 02:42

score 0 · Answer 1 · answered Dec 03 '20 at 22:19

If I'm understanding the R formula documentation properly, the ":" there is the same as the "*" or "BY" specification in SPSS.

If you want a second, uncorrelated random effect with just Group as the subject specification, simply add a second RANDOM subcommand, such as:

/RANDOM= INTERCEPT | SUBJECT(Group) COVTYPE(VC)

Syntax equivalence r vs spss

1 Answers1