Research

Accepted Paper

[13] Beppu, K. and Morikawa, K. (2024).

        Verifiable identification condition for nonignorable nonresponse data with categorical instrumental variables. [link]

        Statistical Theory and Related Fields. Advance online publication.

[12] Kim, J. K. and Morikawa, K. (2023).

       An Empirical Likelihood Approach to Reduce Selection Bias in Voluntary Samples (with discussion) and rejoinder. [link]

        Calcutta Statistical Association Bulletin, 75, 8-27.


[11] Huang, A., Morikawa, K., Friede, T. and Hattori, S. (2023).

        Adjusting for publication bias in meta-analysis via inverse probability weighting using clinical trial registries.

        Biometrics. Accepted for publication. [link]


[10]  Sugasawa, S., Morikawa, K. and Takahata, K. (2022). 

         Bayesian Semiparametric Modeling of Response Mechanism for Nonignorable Missing Data.

         TEST, 31, 101-117. [link]

[9]   Morikawa, K. and Kim, J. K. (2021).

        Semiparametric optimal estimation with nonignorable nonresponse data.

        Annals of Statistics, 49, 2991-3014. [link]

[8]   Tanaka, K., Morikawa, K. et al. (2021). 

        G20 Summit and emergency medical services in Osaka, Japan 

        Acute Medicine & Surgery, 8, e661. [link]

[7]    Morikawa, K., Nagao, H., Ito, S., Terada, Y., Sakai, S. and Hirata, N. (2021).

         Forecasting temporal variation of aftershocks immediately after a main shock using Gaussian process regression.

        Geophysical Journal International, 226, 1018--1035. [link]

[6]    Im, J., Morikawa, K. and Ha, H. T. (2020).

        A least squares-type density estimator using a polynomial function.

        Computational Statistics and Data Analysis, 144, 106882. [link]

[5]    Sado, S., Morikawa, K., Hattori, S., Matsuyama, T., Izawa, J. Iwami, T., Kitamura, Y.,Sobue, T. and Kitamura, T. (2019). 

        Full Moon and Out-of-Hospital Cardiac Arrest in Japan: A Population-Based, Double-Controlled Case Series Analysis.

        Circulation Reports, 1, 199–205. [link]

[4]    Morikawa, K. and Kim, J. K. (2018).

        A discussion of ‘statistical inference for nonignorable missing data problems: a selective review’

        by Niansheng Tang and Yuanyuan Ju. Statistical Theory and Related Fields, 2, 140. [link]

[3]    Morikawa, K. and Kim, J. K. (2018).

        On the equivalence of two semiparametric estimation methods for nonignorable nonresponse, 

        Statistics & Probability Letters, 140, 1--6. [link]

[2]    Morikawa, K. and Kano, Y. (2018).

        Identification problem of transition models for repeated measured data with nonignorable missing,

        Journal of Multivariate Analysis, 165, 216--230. [link]

[1]    Morikawa, K., Kim. J. K. and Kano, Y. (2017).

        Semiparametric maximum likelihood estimation with data missing not at random,

        Canadian Journal of Statistics, 45, 393--409. [link]

Preprint
[1] Beppu, K., Choi, J., Morikawa, K. and Im, J. Model identification enhanced parameter estimation for nonignorable missing outcomes. [link]
[2] Morikawa, K., Terada, Y. and Kim, J. K. Semiparametric adaptive estimation under informative sampling. [link]
[3] Sugasawa, S., Kim, J. K. and Morikawa, K.  Semiparametric Imputation using Latent Sparse Conditional Gaussian Mixtures for Multivariate Mixed Outcomes.[link]
[4] Morikawa, K., Aida, W.  and Beppu, K. Efficient multiple -robust estimation for nonresponse data under informative sampling. [link]

Working Paper
[1] Morikawa, K., Nagao, H., Takahara, K. and Hirata, N. Early aftershock activity estimation by integrating seismic waveforms and earthquake catalog.
[2] Morikawa, K. and Yano, K.  Singular propensity score: reducing variance in weighted estimators