EAP/PV reliability estimates

[cucho_veas]

Hi, I'm comparing two models, a unidimensional Rating scale Rasch model and a multidimensional RSRM. When running the URSRM, I'm trying to obtain the EAP/PV reliability but Conquest says they are unavailable. The basic syntax is:

Title URSRM;
datafile Scale.txt ;
format responses 1-32;
codes 1,2,3,4,5;
model item + step;
estimate !abilities =yes;

[dan_c]

You are presumably using default scoring, such that your “lowest” response category is scored 1 (the lowest value of your code statement). You need a zero-scored response category, and you do that using a score statement:

Code: [Select]

score (1,2,3,4,5) (0,1,2,3,4);

See: https://conquestmanual.netlify.app/s4-00.html#score

[cucho_veas]

Thanks, now it works. However, when using multidimensional syntax, the EAP/PV are available with the original 1-5 response categories. Why is that not possible with both models?

[dan_c]

I'm not sure I follow - you would have to upload a minimum working example so I could recreate it.
https://conquest-forums.acer.edu.au/index.php?topic=1239.0

[cucho_veas]

This is the syntax I used:

Title model 1 factor;
datafile Scale.txt ;
format responses 1-32;
codes 1,2,3,4,5;
score (1,2,3,4,5) (0,1,2,3,4);
model item + step;
estimate !abilities =yes, method = Montecarlo;
reset;
Title model 4 factors;
Datafile Scale.txt;
Format responses 1-32;
codes 1,2,3,4,5;
score (1,2,3,4,5) (1,2,3,4,5) () () () !items (1,2,3,4,5,6,7,8,9);
score (1,2,3,4,5) () (1,2,3,4,5) () () !items (10,11,12,13,14,15);
score (1,2,3,4,5) () () (1,2,3,4,5) () !items (16,17,18,19,20,21,22,23);
score (1,2,3,4,5) () () () (1,2,3,4,5) !items (24,25,26,27,28,29,30,31,32);
Model item+step;
Estimate ! abilities =yes, method=Montecarlo, nodes =2000;

[dan_c]

If you are comparing "model 1 factor" to "model 4 factors", I think it makes sense to impose the same scoring regime in both models (0,1,2,3,4).