Search Results for author: Toru Kitagawa

Found 17 papers, 1 papers with code

Partially identified heteroskedastic SVARs

no code implementations11 Mar 2024 Emanuele Bacchiocchi, Andrea Bastianin, Toru Kitagawa, Elisabetta Mirto

This paper studies the identification of Structural Vector Autoregressions (SVARs) exploiting a break in the variances of the structural shocks.

Adaptive Experimental Design for Policy Learning

no code implementations8 Jan 2024 Masahiro Kato, Kyohei Okumura, Takuya Ishihara, Toru Kitagawa

Setting the worst-case expected regret as the performance criterion of adaptive sampling and recommended policies, we derive its asymptotic lower bounds, and propose a strategy, Adaptive Sampling-Policy Learning strategy (PLAS), whose leading factor of the regret upper bound aligns with the lower bound as the size of experimental units increases.

counterfactual Experimental Design

Treatment Choice, Mean Square Regret and Partial Identification

no code implementations10 Oct 2023 Toru Kitagawa, Sokbae Lee, Chen Qiu

We consider a decision maker who faces a binary treatment choice when their welfare is only partially identified from data.

Individualized Treatment Allocation in Sequential Network Games

no code implementations11 Feb 2023 Toru Kitagawa, Guanyi Wang

Focusing on sequential decision games of interacting agents, this paper develops a method to obtain optimal treatment assignment rules that maximize a social welfare criterion by evaluating stationary distributions of outcomes.

Asymptotically Optimal Fixed-Budget Best Arm Identification with Variance-Dependent Bounds

no code implementations6 Feb 2023 Masahiro Kato, Masaaki Imaizumi, Takuya Ishihara, Toru Kitagawa

We evaluate the decision based on the expected simple regret, which is the difference between the expected outcomes of the best arm and the recommended arm.

Stochastic Treatment Choice with Empirical Welfare Updating

no code implementations3 Nov 2022 Toru Kitagawa, Hugo Lopez, Jeff Rowley

We show analytically a welfare-optimal way of updating the prior using empirical welfare; this posterior is not feasible to compute, so we propose a variational Bayes approximation for the optimal posterior.

Best Arm Identification with Contextual Information under a Small Gap

no code implementations15 Sep 2022 Masahiro Kato, Masaaki Imaizumi, Takuya Ishihara, Toru Kitagawa

We then develop the ``Random Sampling (RS)-Augmented Inverse Probability weighting (AIPW) strategy,'' which is asymptotically optimal in the sense that the probability of misidentification under the strategy matches the lower bound when the budget goes to infinity in the small-gap regime.

Treatment Choice with Nonlinear Regret

no code implementations17 May 2022 Toru Kitagawa, Sokbae Lee, Chen Qiu

The literature focuses on the mean of welfare regret, which can lead to undesirable treatment choice due to sensitivity to sampling uncertainty.

regression

Policy Choice in Time Series by Empirical Welfare Maximization

no code implementations8 May 2022 Toru Kitagawa, Weining Wang, Mengshan Xu

This paper develops a novel method for policy choice in a dynamic setting where the available data is a multivariate time series.

Time Series Time Series Analysis

von Mises-Fisher distributions and their statistical divergence

no code implementations10 Feb 2022 Toru Kitagawa, Jeff Rowley

The von Mises-Fisher family is a parametric family of distributions on the surface of the unit ball, summarised by a concentration parameter and a mean direction.

Paternalism, Autonomy, or Both? Experimental Evidence from Energy Saving Programs

no code implementations18 Dec 2021 Takanori Ida, Takunori Ishihara, Koichiro Ito, Daido Kido, Toru Kitagawa, Shosei Sakaguchi, Shusaku Sasaki

Our estimates confirm that the estimated assignment policy optimally allocates individuals to be treated, untreated, or choose themselves based on the relative merits of paternalistic assignments and autonomous choice for individuals types.

Testing Instrument Validity with Covariates

no code implementations15 Dec 2021 Thomas Carr, Toru Kitagawa

In Monte Carlo exercises we find gains in finite sample power from testing restrictions jointly and distillation.

Evidence Aggregation for Treatment Choice

no code implementations14 Aug 2021 Takuya Ishihara, Toru Kitagawa

Consider a planner who has to decide whether or not to introduce a new policy to a certain local population.

Epidemiology

Constrained Classification and Policy Learning

no code implementations24 Jun 2021 Toru Kitagawa, Shosei Sakaguchi, Aleksey Tetenov

Consistency of the surrogate loss approaches studied in Zhang (2004) and Bartlett et al. (2006) crucially relies on the assumption of correct specification, meaning that the specified set of classifiers is rich enough to contain a first-best classifier.

Classification Fairness

Identification and Inference Under Narrative Restrictions

no code implementations12 Feb 2021 Raffaella Giacomini, Toru Kitagawa, Matthew Read

We consider structural vector autoregressions subject to 'narrative restrictions', which are inequality restrictions on functions of the structural shocks in specific periods.

valid

A note on global identification in structural vector autoregressions

no code implementations8 Feb 2021 Emanuele Bacchiocchi, Toru Kitagawa

In a landmark contribution to the structural vector autoregression (SVARs) literature, Rubio-Ramirez, Waggoner, and Zha (2010, `Structural Vector Autoregressions: Theory of Identification and Algorithms for Inference,' Review of Economic Studies) shows a necessary and sufficient condition for equality restrictions to globally identify the structural parameters of a SVAR.

Who Should Get Vaccinated? Individualized Allocation of Vaccines Over SIR Network

1 code implementation7 Dec 2020 Toru Kitagawa, Guanyi Wang

How to allocate vaccines over heterogeneous individuals is one of the important policy decisions in pandemic times.

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