My research focuses on reliable inference in nonstandard settings with, for example, complex dependence, parameters near the boundary, or singular Fisher information. I develop theory, methods, and computationally efficient software implementing the proposed methods. I regularly collaborate with researchers in biomedicine, psychology, and economics.

Articles

Theory and methods

Asymptotics for likelihood ratio tests of boundary points with singular information and unidentifiable nuisance parameters. K.O. Ekvall, O.G.H. Hössjer, M. Bottai, and J.M.P. Albin.
Submitted · arXiv

Likelihood-based inference with separable correlation matrices. K.O. Ekvall.
Submitted · arXiv | Code | R package

Universal inference for variance components. Y. Zhang, K.O. Ekvall, and A.J. Molstad.
Stat, 2026 · arXiv | Code

Uniform inference in linear mixed models. K.O. Ekvall and M. Bottai.
Biometrika, 2026 · arXiv | Supplement | Code

Fast and reliable confidence intervals for a variance component. Y. Zhang, K.O. Ekvall, and A.J. Molstad.
Biometrika, 2025 · arXiv | Supplement | Code | R package

Direct covariance matrix estimation with compositional data. A.J. Molstad, K.O. Ekvall, and Piotr M. Suder.
Electronic Journal of Statistics, 2024 · arXiv | Supplement

Concave likelihood-based regression with finite-support response variables. K.O. Ekvall and M. Bottai.
Biometrics, 2023 · arXiv | Supplement | Code

Confidence regions near singular information and boundary points with applications to mixed models. K.O. Ekvall and M. Bottai.
Annals of Statistics, 2022 · arXiv | Supplement | Code

Targeted principal components regression. K.O. Ekvall.
Journal of Multivariate Analysis, 2022 · arXiv | Code | R package

Mixed-type multivariate response regression with covariance estimation. K.O. Ekvall and A.J. Molstad.
Statistics in Medicine, 2022 · arXiv | Supplement | R package

Convergence analysis of a collapsed Gibbs sampler for Bayesian vector autoregressions. K.O. Ekvall and G.L. Jones.
Electronic Journal of Statistics, 2021 · arXiv | Code

Consistent maximum likelihood estimation using subsets with applications to multivariate mixed models. K.O. Ekvall and G.L. Jones.
Annals of Statistics, 2020 · arXiv | Supplement

Markov chain Monte Carlo. K.O. Ekvall and G.L. Jones.
Wiley StatsRef, 2019 · PDF

Applications

Validation and comparison of two prearrest prediction scores for in-hospital cardiac arrest survival. H. Karim, E. Piscator, K.O. Ekvall, G. Riva, K.G. Lauridsen, and T. Djärv.
Submitted

Brief stimulus changes signaling extinction enhance resurgence. C.N. Martinez-Perez, J. Williams, C.M. Ritchey, T. Kuroda, K.O. Ekvall, and C.A. Podlesnik.
Submitted

Mediation by thyroid hormone in the relationships between gestational exposure to methylmercury and birth size. K. Gustin, K.O. Ekvall, M. Barman, B. Jacobsson, A. Sandin, A.S. Sandberg, A.E. Wold, M. Vahter, and M. Kippler.
Exposure and Health, 2023