Quantitative Economics

Journal of the Econometric Society

Edited by: Bernard Salanié • Print ISSN: 1759-7323 • Online ISSN: 1759-7331

Quantitative Economics: May, 2026, Volume 17, Issue 2

Identification Through Sparsity in Factor Models: The ℓ1-Rotation Criterion

https://doi.org/10.3982/QE2369
p. 461-496

Simon Freyaldenhoven

Linear factor models are generally not identified. We provide sufficient conditions for identification: Under a natural sparsity assumption (the presence of local factors that affect only subsets of observables), the true loading matrix is the sparsest rotation and can be recovered by minimizing the ℓ1‐norm of the loading matrix. This enables economically meaningful interpretation of the individual factors. More generally, our ℓ1‐rotation criterion offers a novel approach to simplify the loading matrix and performs well relative to existing methods (e.g., Varimax, Kaiser (1958)) in our simulations. We illustrate our method in two economic applications. The R package l1rotation implements the method and facilitates adoption.


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Supplemental Material

Supplement to "Identification Through Sparsity in Factor Models: The ℓ1-Rotation Criterion"

Simon Freyaldenhoven

This supplement contains material not found within the manuscript.

Supplement to "Identification Through Sparsity in Factor Models: The ℓ1-Rotation Criterion"

https://doi.org/10.5281/zenodo.17945084

Simon Freyaldenhoven

The replication package for this paper is available at https://doi.org/10.5281/zenodo.17945084. The Journal checked the data and codes included in the package for their ability to reproduce the results in the paper and approved online appendices.