Source Code
R package spfa that fits semiparametric factor models for continuous and discrete response data. Please refer to Liu & Wang (2022) for more details.
R code that implements the Riemannian trust-region and truncated Newton algorithms for analytic rotation in exploratory factor analysis. For more details, please refer to Liu (2021).
R code that implements the Riemannian conjugate gradient algorithm for the joint maximum likelihood estimation of exploratory item factor models. For more details, please refer to Liu (2020).
R code that computes a second-order probability matching prior for the person parameter in unidimensional IRT models. For more details, please refer to Liu, Hannig, & Pal Majumder (2019).
R code that implements restricted recalibration of IRT models. A brief tutorial and a simulated data example were also included in the archive. For more details, please refer to Liu, Yang, & Maydeu-Olivares (2019).
Fortran code fidgrm that implements fiducial estimation of logistic graded response models. The code was compiled with gfortran 4.8.4 (using the makefile provided in the archive); it also requires libgfortran and liblapack. An example data set (lsat7.dat) and the input file (lsat7.conf, in the format of the standard Fortran 2003 namelist) were also included. For a detailed description of the sampling algorithm, please refer to Liu & Hannig (2017).
R code that calculates bivariate diagnostics for unidimensional two-parameter logistic (2PL) and graded response models using Mplus output. For more details, please refer to Liu & Maydeu-Olivares (2014).
R code that calculates univariate and bivariate diagnostics for unidimensional 2PL and graded response models using the IRTPRO "-prm.txt" file. For more details, please refer to Maydeu-Olivares & Liu (2015).