no code implementations • 11 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.
no code implementations • 8 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.
no code implementations • 10 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.
no code implementations • 11 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.
no code implementations • 6 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.
no code implementations • 3 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.
no code implementations • 15 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.
no code implementations • 17 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.
no code implementations • 8 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.
no code implementations • 10 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.
no code implementations • 18 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.
no code implementations • 15 Dec 2021 • Thomas Carr, Toru Kitagawa
In Monte Carlo exercises we find gains in finite sample power from testing restrictions jointly and distillation.
no code implementations • 14 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.
no code implementations • 24 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.
no code implementations • 12 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.
no code implementations • 8 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.
1 code implementation • 7 Dec 2020 • Toru Kitagawa, Guanyi Wang
How to allocate vaccines over heterogeneous individuals is one of the important policy decisions in pandemic times.