Learning Factors Analysis - A General Method for Cognitive Model Evaluation and Improvement. - Hao Cen; Kenneth R. Koedinger; Brian Junker (Intelligent Tutoring Systems, 2006)

Is Over Practice Necessary? - Improving Learning Efficiency with the Cognitive Tutor through Educational Data Mining. - Hao Cen; Kenneth R. Koedinger; Brian Junker (AIED, 2007)

Using Item-type Performance Covariance to Improve the Skill Model of an Existing Tutor. - Philip I. Pavlik; Hao Cen; Lili Wu; Kenneth R. Koedinger (EDM, 2008)

Comparing Two IRT Models for Conjunctive Skills. - Hao Cen; Kenneth R. Koedinger; Brian Junker (Intelligent Tutoring Systems, 2008)

Performance Factors Analysis - A New Alternative to Knowledge Tracing. - Philip I. Pavlik; Hao Cen; Kenneth R. Koedinger (AIED, 2009)

Learning Factors Transfer Analysis: Using Learning Curve Analysis to Automatically Generate Domain Models. - Philip I. Pavlik Jr.; Hao Cen; Kenneth R. Koedinger (EDM, 2009)