Posted on 6 January 2011 by Mitch Abdon
When upgrading to a new version of a software, I am used to uninstalling the old version first because most software require this or I am concerned that different versions installed will result in conflicts. So, I do the same when I install newer versions of Stata. If I already have the new one, why will I need the old ones?
Then came an answer today! I was trying run Tristan Zajonc’s -openirt-* help file examples to see how the program works. I was using version 11.1. The program returned an error, which I thought unlikely because the examples come from the program’s help file (although this is not always a guarantee…). I tried the other examples and the same error occurs. Just to be sure, I opened openirt.ado to see which version the program was set to so that I can run the same examples using this version and see if it works. One hiccup—I have no other versions currently installed! I had to install version 10 all over again and update it to 10.1 as -openirt- was set to run in version 10.1. -openirt- ran smoothly in version 10.1. Problem solved; lesson learned.
I remember a discussion about this on Statalist, here is the thread.
*-openirt– (Zajonc 2010) estimates Item Response Theory models for dichotomous data.