latent regression model in mirt

[Balal Ezanloo]

Hi Phil

I know "mirt" can handle below model. i can run it by below syntax, but i am not sure about it. also where is the regression coefficient of "ksi" on Z in output?any help?

covdata <- # a binary matrix for 1000 persone in 5 variables(v1:v5)

z <- rowMeans(covdata)

data <- # another binary matrix for the same 1000 persone in 5 variables

LRM.2pl.out <- mirt(data , 1, '2PL', covdata=covdata, formula = ~ z)

[Phil Chalmers]

Xi is set to 1 for the 2PL model for identification. Otherwise, you could freely estimate the latent variable variance term if you set one of the item slope parameters  to 1 (this is a common strategy in SEM). 

Phil

--
You received this message because you are subscribed to the Google Groups "mirt-package" group.
To unsubscribe from this group and stop receiving emails from it, send an email to mirt-package+unsubscribe@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[Balal Ezanloo]

Thanks

Did I introduce the model correctly to the "mirt"? i am not sure about it.

Also,  in the output did i find correctly the regression coefficient of "ksi" on Z, as below?

 

                F1

  (Intercept)  0.000

r.p.comleted 1.872

Phil

To unsubscribe from this group and stop receiving emails from it, send an email to mirt-package...@googlegroups.com.

[Balal Ezanloo]

Hi Phil

How can i add an intercept of Z in "formula" part

LRM.2pl.out <- mirt(data , 1, '2PL', covdata=covdata, formula = ~ z) 

[Phil Chalmers]

Only by modifying the starting values explicitly via the pars input. But, why would you want to? This is fixed at 0 for identification reasons.

Phil

To unsubscribe from this group and stop receiving emails from it, send an email to mirt-package+unsubscribe@googlegroups.com.

[balal izanloo]

Thanks

I have a model that presented hear. other peoples run it by "mplus" but i want to run it by "mirt". "mirt" results is not the same as "mplus" one. i want to add intercepts to my syntax in mirt and compare the results.