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Ito Tsubasa
| Faculty of Economics and Business Modern Economics and Management Economic Analysis | Associate Professor |
| Faculty of Economics and Business | Associate Professor |
Researcher basic information
■ Degree■ URL
researchmap URL■ Research Keywords and Fields
Research KeywordResearch Field■ Educational Organization
- Bachelor's degree program, School of Economics and Business
- Master's degree program, Graduate School of Economics and Business
- Doctoral (PhD) degree program, Graduate School of Economics and Business
Research activity information
■ Papers- Potential Biases of the Transmission Risks of COVID-19 estimated by Contact Tracing Surveys in Japan
Tsubasa Ito; Takahiro Otani; Tatsuhiko Anzai; Takashi Okumura; Kunihiko Takahashi
Epidemiology, Biostatistics, and Public Health, 18, 1, 55, 61, Milano University Press, 01 Aug. 2023, [Peer-reviewed]
Scientific journal, Introduction: Contact tracing surveys are being conducted to identify and isolate close contacts of an identified patient to reduce the spread of coronavirus disease (COVID-19). However, the estimates of risk indexes based on information obtained from the surveys and normally used in practice can have biases comparing with true magnitude of risks of infection and spread.Method: We evaluated whether the estimates of the risk indexes obtained from information of the active epidemiological surveillance, contact tracing surveys in Japan, are suitable for quantitative assessment of the risk factors of COVID-19, using pseudo data via a simulation study. We discussed two types of risks considered in the issue of infectious disease, the probability of infection and that of spreading, and the estimates of these risks.Results and Discussion: A naive method to estimate the risks of infection and spreading of COVID-19 is to calculate the ratio of infected patients to close contacts and the ratio of patients who infected others to all the confirmed patients, respectively. However, these estimates could possibly have significant biases and result in being ineffective for both the exploration and the quantitative assessment of the risk factors in the following ordinary cases: a person contacts closely with many confirmed patients, or a confirmed patient contact closely with many people. Then, some steps are needed to reduce such possible biases for the estimation the risks of both the infection and spreading of COVID-19. - Grouped generalized estimating equations for longitudinal data analysis
Tsubasa Ito; Shonosuke Sugasawa
Biometrics, Wiley, 02 Aug. 2022, [Peer-reviewed]
Scientific journal - Empirical best linear unbiased predictors in multivariate nested-error regression models
Tsubasa Ito; Tatsuya Kubokawa
Communications in Statistics - Theory and Methods, 50, 10, 2224, 2249, Informa UK Limited, 19 May 2021, [Peer-reviewed]
Scientific journal - Corrected empirical Bayes confidence region in a multivariate Fay–Herriot model
Tsubasa Ito; Tatsuya Kubokawa
Journal of Statistical Planning and Inference, 211, 12, 32, Elsevier BV, Mar. 2021, [Peer-reviewed]
Scientific journal - Excess Mortality From Suicide During the Early COVID-19 Pandemic Period in Japan: A Time-Series Modeling Before the Pandemic
Tatsuhiko Anzai; Keisuke Fukui; Tsubasa Ito; Yuri Ito; Kunihiko Takahashi
Journal of Epidemiology, 31, 2, 152, 156, Japan Epidemiological Association, 05 Feb. 2021, [Peer-reviewed]
Scientific journal - Improved confidence regions in meta-analysis of diagnostic test accuracy
Tsubasa Ito; Shonosuke Sugasawa
Computational Statistics and Data Analysis, 153, 107068, 107068, Elsevier BV, Jan. 2021, [Peer-reviewed]
Scientific journal - Robust estimation of mean squared error matrix of small area estimators in a multivariate Fay–Herriot model
Tsubasa Ito; Tatsuya Kubokawa
Japanese Journal of Statistics and Data Science, 3, 1, 39, 61, Springer Science and Business Media LLC, Jun. 2020, [Peer-reviewed]
Scientific journal
- 卒業論文, 2024年, 学士課程, 経済学部
- 応用統計学特論Ａ, 2024年, 修士課程, 経済学院
- 演習Ⅴ（２単位）, 2024年, 学士課程, 経済学部
- 応用統計学特論Ｂ, 2024年, 修士課程, 経済学院
- 演習Ⅵ（２単位）, 2024年, 学士課程, 経済学部
- 現代経済経営演習Ⅰ, 2024年, 修士課程, 経済学院
- 演習Ⅶ（２単位）, 2024年, 学士課程, 経済学部
- 現代経済経営演習Ⅱ, 2024年, 修士課程, 経済学院
- 演習Ⅷ（２単位）, 2024年, 学士課程, 経済学部
- 演習Ⅰ（２単位）, 2024年, 学士課程, 経済学部
- 公共政策特別研究ⅡＡ, 2024年, 専門職大学院, 公共政策学教育部
- 演習Ⅱ（２単位）, 2024年, 学士課程, 経済学部
- 公共政策特別研究Ⅰ, 2024年, 専門職大学院, 公共政策学教育部
- 演習Ⅲ（２単位）, 2024年, 学士課程, 経済学部
- 演習Ⅳ（２単位）, 2024年, 学士課程, 経済学部
- 演習Ⅴ（２単位）, 2024年, 学士課程, 経済学部
- 演習Ⅵ（２単位）, 2024年, 学士課程, 経済学部
- 演習Ⅶ（２単位）, 2024年, 学士課程, 経済学部
- 演習Ⅷ（２単位）, 2024年, 学士課程, 経済学部
- 現代日本制度ⅠD, 2024年, 学士課程, 現代日本学プログラム課程
- 統計学, 2024年, 学士課程, 全学教育
- 計量経済学Ⅰ, 2024年, 学士課程, 経済学部
- 統計分析, 2024年, 専門職大学院, 公共政策学教育部
- High dimensional multivariate linear mixed model and application to small area estimation
Grants-in-Aid for Scientific Research
30 Aug. 2019 - 31 Mar. 2021
Ito Tsubasa
Multivariate small are estimation problem, especially the Fay-Herriot model in which we only obtain aggregated data for each area is considered in the setting where the ratio of the square of the dimension of the observed vectors and the number of areas converges to a constant. The convergence rates of the estimators of the parameters in the model are shown, noting that the dimensions of these parameters also increase in this setting. Small area mean vectors are predicted by the empirical best linear unbiased predictors, which can be obtained by substituting the estimators of the parameters into its bayes estimator. As its prediction risks, the mean squared error matrix and the confidence interval are constructed such that the approximation errors are of second order regarding the number of areas. It is shown that the additional terms appear in both compared with the results obtained when the dimension of the observed vectors is fixed.
Japan Society for the Promotion of Science, Grant-in-Aid for Research Activity Start-up, 19K23242
