specifying correct lmer_alt models

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This topic contains 1 reply, has 1 voice, and was last updated by  statmerkur 1 week, 4 days ago.

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  • #241

    statmerkur
    Participant

    Until Rune Haubo pointed out that he cannot see how these models (using the double-bar notation for factorial designs in the way I do in m1) are relevant I was quite sure that they made sense:
    library("lme4")
    m1 <- afex::lmer_alt(angle ~ recipe + (recipe || replicate), cake)

    He instead suggests that one should use

    m2 <- lmer(angle ~ recipe +
              (0 + dummy(recipe, "A") | replicate) +
              (0 + dummy(recipe, "B") | replicate) +
              (0 + dummy(recipe, "C") | replicate), cake)

    or

    m3 <- lmer(angle ~ recipe + (1 | replicate) +
              (0 + dummy(recipe, "A") | replicate) +
              (0 + dummy(recipe, "B") | replicate) +
              (0 + dummy(recipe, "C") | replicate), cake)

    which are different from m1 and equivalent to
    m4 <- afex::lmer_alt(angle ~ recipe + (0 + recipe || replicate), cake)
    and
    m5 <- afex::lmer_alt(angle ~ recipe + (1|replicate) + (0 + recipe || replicate), cake)

    I’m now quite puzzled because AFAICS you and others (but I don’t remember them) use m1 in the afex vignettes and also here.
    What is the correct way to specify a lmer_alt model for categorical independent variables?

  • #244

    statmerkur
    Participant

    EDIT (I don’t know how I can edit or delete my question?!): I realized that this is a broader question that is not directly related to lmer_alt but more so to lmer and mixed models in general. So I decided to post it on CrossValidated.

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Author: statmerkur