[Rasch] Help! TAM question

Rense Lange rense.lange at gmail.com
Sun Jan 26 02:50:09 AEDT 2020

Is there anyone here familiar with TAM? I am trying to fit a 3 dim model, using the lavaan method … the data are in “resp”

Based on the 2-dim example in the (terse) documentation, I am trying the code:

tammodel <- "
    F1=~ 1*I1__I20
    F2=~ 1*I21__I30
    F3=~ 1*I31__40
    # Alternatively to the factor 1 one can use the item type Rasch
    F1 ~~ F1
    F2 ~~ F2
    F3 ~~ F3
    F1 ~~ F2
    F1 ~~ F3
    F2 ~~ F3
model3fac <- TAM::tamaan( tammodel, resp, irtmodel = "RSM", control=list(maxiter=200))


Although the 2-dim version works fine, this one doesn’t. I get:

Error in seq.default(which(items == v10[1]), which(items == v10[2])) : 
  'to' must be of length 1

Does anyone know?
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