[Rasch] help with TAM

Rense Lange rense.lange at gmail.com
Mon Nov 4 06:41:27 AEDT 2019


I am trying to fit a 2D rating scale model using TAM in R on my MacBook. 

Using the code shown at the end,the string prints fine:

		"\n\nLAVAAN MODEL:\n\tSF =~ SFQ01__SFQ18\n\tCADDS =~ CADSS01__CADSS19\n\tSF ~~ SF\n\tCADSS ~~ CADSS\n\tSF ~~ CADSS\nITEM TYPE:\n\tALL(RSM);\n\t"

But then I get the error message:

		Error in seq.default(ind1, ind2) : 'from' must be of length 1

I cannot find a solution for this. Does anyone know what I do wrong?

Rense Lange



Here is my code:

#Load TAM library
library("TAM")

D1 <- read.csv("ratsonly2.csv")

tammodel <- "

LAVAAN MODEL:
	SF =~ SFQ01__SFQ18
	CADDS =~ CADSS01__CADSS19
	SF ~~ SF
	CADSS ~~ CADSS
	SF ~~ CADSS
ITEM TYPE:
	ALL(RSM);
	"
print(tammodel)

mod <- tamaan(tammodel,resp=D1)

The data I use looks fine to me. Here are some rows and columns (there are more rows and columns than shown here). The CADSS.. columns are the next columns in the file.

SFQ01	SFQ02	SFQ03	SFQ04	SFQ05	SFQ06	SFQ07	SFQ08 ……
3	3	2	1	2	3	3	2
3	2	3	1	0	0	0	0
4	0	4	2	2	0	0	1
3	2	4	2	3	1	1	2
3	1	3	2	3	2	2	2


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