act.nrm: ACT Mathematics Test 1997-1998 Nominal Response Model

Description Usage Format Source


This (unidimensional )dataset includes nominal response model item parameter estimates for two groups. There are 60 items, all of which are common items. The estimates are from the 1997 and 1998 ACT mathematics test. The item parameters were obtained from the examples for the software nreq written by Bradley Hanson.




A list of length two. The matrices in the two list elements contain nominal response model item parameters for 1997 and 1998 respectively. The first six columns in each matrix are the slope parameters and the next six columns are the category difficulty parameters.


Kim, J.-S. & Hanson, B. A. (2002). Test Equating Under the Multiple-Choice Model. Applied Psychological Measurement, 26(3), 255-270.

The item parameters can be found here

plink documentation built on May 1, 2019, 8:07 p.m.