Using Lasso and Adaptive Lasso to Identify DIF in Multidimensional 2PL Models

The r file Reg_DIF_Main_Functions includes the main functions for three methods (LASSO EM, LASSO EMM, Adaptive LASSO).

The r file EMsteps includes functions for the E-step and M-steps used in main functions.

The file LRTcode includes code for running likelihood ratio tests.

NonUnifAllSims is code for non-uniform DIF simulation studies.

Algorithm details can be found in the RunningDocumentation,