ltm: Latent Trait Models under IRT

Analysis of multivariate dichotomous and polytomous data using latent trait models under the Item Response Theory approach. It includes the Rasch, the Two-Parameter Logistic, the Birnbaum's Three-Parameter, the Graded Response, and the Generalized Partial Credit Models.

Version: 1.0-0
Depends: R (≥ 2.14.0), MASS, msm, polycor
Published: 2013-12-20
Author: Dimitris Rizopoulos
Maintainer: Dimitris Rizopoulos <d.rizopoulos at>
License: GPL-2 | GPL-3 [expanded from: GPL (≥ 2)]
NeedsCompilation: no
Citation: ltm citation info
Materials: NEWS
In views: Multivariate, Psychometrics
CRAN checks: ltm results


Reference manual: ltm.pdf
Package source: ltm_1.0-0.tar.gz
Windows binaries: r-devel:, r-release:, r-oldrel:
OS X Snow Leopard binaries: r-release: ltm_1.0-0.tgz, r-oldrel: ltm_1.0-0.tgz
OS X Mavericks binaries: r-release: ltm_1.0-0.tgz
Old sources: ltm archive

Reverse dependencies:

Reverse depends: difR, infutil, irtoys, kequate, PerFit
Reverse imports: CTTShiny, IRTShiny, userfriendlyscience
Reverse suggests: catIrt