Associate Professor of Psychology
Address: 425 Psychology Bldg.
603 E. Daniel Street
Champaign, IL 61820
My current research concerns three lines of work:
(1) Combinatorial data analysis of individual differences based on multiple proximity matrices observed from different data sources (e.g., subjects, experimental conditions, time points);
(2) Large-scale nonmodel-based clustering, with particular focus on the p-median model;
(3) Cognitively Diagnostic Modeling
Köhn, H. F., & Chiu, C.-Y. (in press). Attribute hierarchy models in cognitive diagnosis: Identifiability of the latent attribute space and conditions for completeness of the Q-matrix. Journal of Classification.
Köhn, H. F., & Chiu, C.-Y. (2018). How to build a complete Q-matrix for a cognitively diagnostic test. Journal of Classification, 35, 273–299.
Köhn, H. F. (2017). Citation classics commentary on Greenhouse and Geisser (1959): On methods in the analysis of profile data. Psychometrika, 82, 1209–1211.
Köhn, H. F., & Chiu, C.-Y. (2017). A procedure for assessing the completeness of the Q-matrices of cognitively diagnostic tests. Psychometrika, 82, 112–132.
Köhn, H. F., & Chiu, C.-Y. (2016). A proof of the duality of the DINA model and the DINO model. Journal of Classification, 33, 171-184.
Chiu, C.-Y., & Köhn, H. F. (2016). The Reduced RUM as a logit model: Parameterization and constraints. Psychometrika, 81, 350-370.
Chiu, C.-Y., & Köhn, H. F. (2016). Consistency of cluster analysis for cognitive diagnosis: The Reduced Reparameterized Unified Model and the General Diagnostic Model. Psychometrika, 81, 585-610.
Köhn, H. F., & Hubert, L. J. (2015). Hierarchical cluster analysis. Wiley StatsRef: Statistics Reference Online (WSR).
Köhn, H. F., Chiu, C.-Y., & Brusco, M. J. (2015). Heuristic cognitive diagnosis when the Q-matrix is unknown. British Journal of Mathematical and Statistical Psychology, 68, 268-291.
Köhn, H. F. (2011). A review of multiobjective programming and its application in quantitative psychology. Journal of Mathematical Psychology, 55, 386-396.
Köhn, H. F. (2010). Representation of individual differences in rectangular proximity data through anti-Q matrix decomposition. Computational Statistics and Data Analysis, 54, 2343-2357.
Köhn, H. F., Steinley, D., & Brusco, M. J. (2010). The p-median model as a tool for clustering psychological data. Psychological Methods, 15, 87-95.
Brusco, M. J., & Köhn, H. F. (2009). Clustering qualitative data based on binary equivalence relations: a variable neighborhood search procedure for the clique partitioning problem. Psychometrika, 74, 685-703.
Brusco, M. J., & Köhn, H. F. (2009). Exemplar-based clustering via simulated annealing: a comparison to affinity propagation and vertex substitution. Psychometrika, 74, 457-475.
Brusco, M. J., & Köhn, H. F. (2008). Optimal partitioning of a data set based on the p-median model. Psychometrika, 73, 89-105.
Brusco, M. J., & Köhn, H. F. (2008). Comment on “Clustering by passing messages between data points”. Science, 319, 726c.
Brusco, M. J., Köhn, H. F., & Stahl, S. (2008). Heuristic implementation of dynamic programming for matrix permutation problems in combinatorial data analysis. Psychometrika, 73, 503-522.
Click on the title to check out these pictures from the classroom remodeling project in the basement. A second project to replace the elevators will begin in September. Beginning with the freight elevator, each elevator will be out of service for three months. To get quickly from one floor to another, and improve your fitness, we will encourage the use of the stairs. The repainting of the northeast stairwell has been completed, and the painter is starting on the southwest stairwell.