topic Re: plots=IIC in proc IRT in SAS Procedures

plots=IIC in proc IRT

lboyd — Thu, 06 Apr 2017 18:58:03 GMT

I am running:

ods graphics on;
proc irt data=ff1 RESFUNC=graded plots=iic;
var fv_preptime fv_fresh fv_prepknow fv_filling fv_restarauntserv fv_sugar fv_dontlook fv_costtoomuch;
run;
ods graphics off;

on data that has 5 categories (ie. never, rarely, neutral, often, and always). I am trying to get IIC plots, not ICC plots, but I keep getting an error:

NOTE: The IRT procedure is experimental in this release of the SAS system.
103 proc irt data=ff1 RESFUNC=graded plots=iic;
---
1
WARNING 1-322: Assuming the symbol ICC was misspelled as iic.

I have run it other ways including plots=all, plots=(scree(unpack) iic) and I just can't seem to get the IIC plots.

Any suggestions?

Thanks!

Re: plots=IIC in proc IRT

Rick_SAS — Fri, 07 Apr 2017 15:10:57 GMT

Try it on a simple example. Perhaps there is something degenerate about your data:

data IrtUni;
   input item1-item8 @@;
   datalines;
1 0 0 0 1 1 2 1 1 1 1 1 1 3 3 3 0 1 0 0 1 1 1 1 1 0 0 1 0 1 2 3 0 0 0
0 0 1 1 1 1 0 0 1 0 1 3 3 0 0 0 0 0 1 1 3 0 0 1 0 0 1 2 2 0 1 0 0 1 1
3 3 0 1 0 0 1 2 2 1 
; 

proc irt data=IrtUni plots=ICC;
   var item1-item8;
run;

Re: plots=IIC in proc IRT

lboyd — Fri, 07 Apr 2017 15:15:08 GMT

Hi Rick,

Thank you for your response! I just ran what you posted and changed plots=IIC and I still got this error:

237 proc irt data=IrtUni plots=IIC;
---
1
WARNING 1-322: Assuming the symbol ICC was misspelled as IIC.

Any other thoughts as to why it doesn't like IIC?

My data is 5 categories (strongly agree=1, agree=2, neutral=3, disagree=4, and stronlgy disagree=5).

Thank you!

Re: plots=IIC in proc IRT

Rick_SAS — Fri, 07 Apr 2017 15:25:08 GMT

The IIC plot was introduced in SAS/STAT 13.2. (13.2 = SAS 9.4m2) I conjecture that you are running 13.1 and so that plot is not available. You can check your SAS version by using

%put SYSVLONG = &SYSVLONG;

Re: plots=IIC in proc IRT

lboyd — Fri, 07 Apr 2017 15:27:00 GMT

I have SYSVLONG = 9.04.01M1P120413

Re: plots=IIC in proc IRT

Rick_SAS — Fri, 07 Apr 2017 15:32:24 GMT

Right, and the M1 means you are running SAS 9.4m1 = SAS/STAT 13.1. There have been three releases of SAS since then (13.2, 14.1, and 14.2).