Can I see coefficients of difficulty and discrimination in summary() function?

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Seongho Bae

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Jan 27, 2014, 11:25:31 PM1/27/14
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Hi, Pill.

I write again in this forum.

I was encountered one trouble.

Can I see coefficients of difficulty and discrimination in summary () function?

I can not see any coefficients of difficulty and discrimination in summary() function without coef().

Like this:

> summary(GAT.stage2.result)

Factor loadings metric: 
            F1       h2
언어1   0.2296 0.052715
언어2   0.1335 0.017832
언어3  -0.0195 0.000381
언어4   0.2846 0.081009
언어5   0.3418 0.116849
언어6   0.2252 0.050724
언어7   0.9796 0.959566
언어8   0.1128 0.012717
언어9  -0.3541 0.125385
언어10  0.7331 0.537432
언어11  0.1619 0.026206
언어12 -0.1264 0.015974
언어13 -0.0717 0.005145
언어14  0.4049 0.163958
언어15  0.3617 0.130832
언어16  0.8687 0.754685
언어17  0.3283 0.107776
언어18  0.1184 0.014027
언어19  0.5138 0.263964
언어20  0.2753 0.075810
언어21  0.3500 0.122486
언어22  0.5244 0.274947
언어23 -0.4178 0.174549
언어24  0.4786 0.229085
언어25  0.2289 0.052384

SS loadings:  4.366 

Factor covariance: 
   F1
F1  1

So, I want to get your advice.

Thanks a lot every times.

--
Seongho

Phil Chalmers

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Jan 28, 2014, 8:47:45 AM1/28/14
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No, summary() only provides standardized loadings for most models. That being said, you could always modify the outputs yourself to get what you are looking for (this is R, after all). Perhaps the as.data.frame() function is what you are looking for?

dat <- expand.table(LSAT7)
mod <- mirt(dat, 1, SE = T)
t(as.data.frame(coef(mod)))

Phil


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Seongho Bae

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Apr 3, 2014, 2:08:55 AM4/3/14
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I was just want to save difficulty and discrimination coefficient .csv file. So, I tried to use "as.data. frame()" function to save them. ;)

2014년 1월 28일 화요일 오후 10시 47분 45초 UTC+9, Phil Chalmers 님의 말:

Phil Chalmers

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Apr 3, 2014, 9:38:01 AM4/3/14
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You also could have used the more verbose mod2values() function since it returns a lot more information (including which parameters were freely estimated, which is nice for simulations). I tend to use that approach in my simulations. Cheers.

Phil


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