Error Message in itemfit

[eliandr...@gmail.com]

I am trying to run item fit statistics on a graded response model and am getting an error message that I don't know what to do about.  This is my model statement:

grmmod <- mirt(allclass, mirtss, itemtype = 'graded', method = "QMCEM", IRTpars = TRUE)

This is what I am using for the item fit:

moditemfit <- itemfit(grmmod, c('X2', 'G2'), method = 'MAP', Theta = ss_fscores, impute = 2, QMC = TRUE, Zh = F)

This is the error message I am getting:

Error in data.frame(value, row.names = rn, check.names = FALSE, check.rows = FALSE) : 
  row names supplied are of the wrong length

Any idea why this might happen?  What could I do to resolve this error?

[Phil Chalmers]

There's a lot going on here that seems incorrect. First, I'd recommend updating mirt to the lastest version as yours looks out of date.

On Thu, Mar 16, 2017 at 10:11 AM, <eliandr...@gmail.com> wrote:

I am trying to run item fit statistics on a graded response model and am getting an error message that I don't know what to do about.  This is my model statement:

grmmod <- mirt(allclass, mirtss, itemtype = 'graded', method = "QMCEM", IRTpars = TRUE)

IRTpars is not a valid argument to mirt().

 

This is what I am using for the item fit:

moditemfit <- itemfit(grmmod, c('X2', 'G2'), method = 'MAP', Theta = ss_fscores, impute = 2, QMC = TRUE, Zh = F)

If you are providing your own fscores, impute is not supported, nor is method. QMC is not a valid input for either of the requested fit statistics. Zh is also no longer a valid input.

 

This is the error message I am getting:

Error in data.frame(value, row.names = rn, check.names = FALSE, check.rows = FALSE) : 
  row names supplied are of the wrong length

Any idea why this might happen?  What could I do to resolve this error?

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