Warning when detecting DIF for binary and graded items together

Yiqi Zheng

unread,

May 30, 2024, 3:14:18 AMMay 30

to mirt-package

Hello Phill,

I'm working on detecting gender DIF for a booklet with most binary items and some graded items. I want to fit 2PL for binary items and GPCM for graded items.

I have already put the graded and binary item names into two lists, which are bk15_graded_items and bk15_binary_items. When I run the codes below, I keep having the warning Error: Keywords and latent trait/class names must differ from colnames(data) for the codes I highlight as red below. I check the colnams which are all item original names, such as MQ12D02A MQ12D02B MQ12D03 MQ12D04 MQ12D05 MQ12D06A MQ12D06B MQ12D07A. Could you please me have a look to see why I have this warning?

bk15_graded_spec <- paste(bk15_graded_items, "=1-GPCM", collapse=", ")
bk15_binary_spec <- paste(bk15_binary_items, "=1-2PL", collapse=", ")

bk15_model_spec <- paste(bk15_graded_spec, bk15_binary_spec, collapse=", ")

bk15_fit <- mirt(bk15_data[, c(bk15_graded_items, bk15_binary_items)], model = bk15_model_spec, itemtype = 'mixed')

bk15_dif_results <- dif(bk15_fit, group = bk15_data$gender)

Yiqi Zheng

unread,

May 30, 2024, 3:16:51 AMMay 30

to mirt-package

Below are some codes for your reference. Thank you!

> bk15_model_spec
[1] "MQ12B03 =1-GPCM, MQ12B05C =1-GPCM, MQ12D07B =1-GPCM MQ12B01 =1-2PL, MQ12B02 =1-2PL, MQ12B04A =1-2PL, MQ12B04B =1-2PL, MQ12B04C =1-2PL, MQ12B05A =1-2PL, MQ12B05B =1-2PL, MQ12R01 =1-2PL, MQ12R02A =1-2PL, MQ12R02B =1-2PL, MQ12R02C =1-2PL, MQ12D01 =1-2PL, MQ12D02A =1-2PL, MQ12D02B =1-2PL, MQ12D03 =1-2PL, MQ12D04 =1-2PL, MQ12D05 =1-2PL, MQ12D06A =1-2PL, MQ12D06B =1-2PL, MQ12D07A =1-2PL, MQ12D08A =1-2PL, MQ12D08B =1-2PL"

> bk15_data[, c(bk15_graded_items, bk15_binary_items)]
MQ12B03 MQ12B05C MQ12D07B MQ12B01 MQ12B02 MQ12B04A MQ12B04B MQ12B04C MQ12B05A MQ12B05B MQ12R01 MQ12R02A MQ12R02B MQ12R02C MQ12D01
1 NA 0 1 1 0 0 1 0 1 1 1 1 1 1 0
2 2 1 0 1 0 0 1 1 1 1 0 1 1 1 1
3 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0
4 2 0 0 1 0 0 0 0 1 1 0 0 0 0 0
5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
7 NA 0 0 0 0 0 0 0 0 0 0 0 0 0 0
8 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0
9 2 0 1 1 1 1 1 1 1 1 1 1 1 1 1
10 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
11 0 0 0 1 0 0 1 0 1 1 0 0 0 0 0
12 NA 0 2 1 0 0 1 1 0 1 1 1 1 0 1
13 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0
14 NA 0 0 0 0 0 0 1 0 0 0 0 0 0 0
15 2 0 0 1 0 0 1 1 0 1 0 1 1 0 1
16 2 0 2 1 1 1 1 1 1 1 1 1 0 1 1
17 0 0 0 0 0 0 0 0 1 1 1 1 1 1 0
18 NA 0 0 0 1 1 0 0 1 1 1 0 0 0 0
19 NA 0 0 0 0 0 0 0 0 0 0 0 0 0 0
20 2 0 0 1 0 0 1 0 0 1 0 0 0 0 1
21 NA 0 2 1 1 0 0 1 1 1 1 0 0 0 0
22 0 0 0 1 0 0 0 0 1 1 0 1 0 0 1
23 2 0 0 1 0 1 1 1 1 1 1 1 1 1 1
24 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
25 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
26 0 0 0 1 0 0 0 1 0 0 0 1 1 0 0
27 2 1 2 1 0 1 1 1 1 1 1 1 1 1 1
28 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1
29 2 1 0 1 1 0 1 1 1 1 0 0 0 0 1
30 0 0 0 1 0 1 1 0 1 1 0 0 0 0 0
31 NA 0 0 0 1 0 1 0 0 1 0 0 0 0 0
32 2 0 0 1 1 0 1 1 0 1 0 0 0 0 1
33 2 0 2 1 1 1 1 1 0 0 1 1 1 1 1
34 NA 0 1 0 0 0 0 0 1 1 0 0 0 0 0
35 NA 0 0 0 0 0 0 0 1 0 0 0 0 0 0
36 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0
37 2 0 0 1 1 1 1 1 1 1 1 1 1 0 1
38 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
39 NA 0 0 1 0 1 0 1 1 1 1 1 1 1 1
40 0 0 0 0 0 1 0 1 1 1 1 0 0 0 1

Phil Chalmers

unread,

May 30, 2024, 4:40:10 PMMay 30

to Yiqi Zheng, mirt-package

dif() is not a function defined in mirt (DIF() is, however). It also doesn't look like you're defining a supported itemtype, or even a valid model definition. Might help to refer to the documentation in help(mirt.model) before moving forward.

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...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/mirt-package/3a4c1ffb-20af-4088-af5e-af766939e17en%40googlegroups.com.

Reply all

Reply to author

Forward