In this study, we illustrate a tradeoff between the short-run positive and long-run negative effects of monetary easing by using a dynamic stochastic general equilibrium model embedding endogenous growth with creative destruction and sticky prices due to menu costs. Although a monetary easing shock increases the level of consumption because of price stickiness, it lowers the frequency of creative destruction (i.e., product substitution) because inflation reduces the reward for innovation via menu cost payments. When calibrated to the U.S. economy, the model suggests that the adverse effect dominates in the long run.

To analyze the relationship between inflation and economic growth, we construct an endogenous growth model with creative destruction, incorporating sticky prices due to menu costs. Price changes reduce the reward for innovation and thus lower the frequency of creative destruction. Central banks can maximize the growth rate by setting their inflation target at the negative of a fundamental growth rate. While the optimal inflation rate may be greater than the growth-maximizing inflation rate, our calibrated model shows that the optimal inflation rate is close to the growth-maximizing inflation rate and that a deviation from the optimal level has sizable impacts.

This paper has two objectives. One is to survey previous studies concerning indicators of technological proximity and distance to identify technological relationships between firms, particularly in terms of spillovers of technology and knowledge. The other objective is to reexamine the spillover effect in research and development by combining the traditional technological proximity with a measurement of within-field technological relationships, which is based on patent citation overlaps. I find that the average technological proximity is increasing over these three decades in the United States and within-field technological proximity shows sizable variations, and that the spillover effect is underestimated unless the changes in within-field proximities are taken into account.

This paper provides a microfoundation for distributions of technical inefficiency in parametric stochastic production frontier analysis. It shows that dial-setting technology a la Jovanovic and Nyarko (1996) implies a gamma distribution with a specific set of parameters that depends on a manager's experience or his/her prediction ability. (C) 2015 Elsevier B.V. All rights reserved.

In this study, we investigate the qualitative and quantitative effects of an R&D subsidy for a clean technology and a Pigouvian tax on a dirty technology on environmental R&D when it is uncertain how long the research takes to complete. The model is formulated as an optimal stopping problem, in which the number of successes required to complete the R&D project is finite and learning about the probability of success is incorporated. We show that the optimal R&D subsidy with the consideration of learning is higher than that without it. We also find that an R&D subsidy performs better than a Pigouvian tax unless suppliers have sufficient incentives to continue cost-reduction efforts after the new technology successfully replaces the old one. Moreover, by using a two-project model, we show that a uniform subsidy is better than a selective subsidy. (C) 2015 Elsevier B.V. All rights reserved.

2019年度は二つの点でプロジェクトを展開させた。第一に、日本の企業レベルの研究開発投資がトレンド・インフレ率に対してネガティブに反応すること、ただしその効果は大企業であるほど小さくなることを実証的に示した。これまでに展開してきた理論においては、インフレによってもたらされる価格改定費用が研究開発のインセンティブを阻害するものの、その影響は企業のタイプによって異なり、研究開発能力の高い企業ほど影響を受けにくいことを基本的なメカニズムとしていた。その結果として、インフレは能力の低い企業から高い企業への資源再配分を促し、経済全体の成長を促進する効果を持つとしていたわけだが、今回の実証研究により、その理論的メカニズムの現実的な有意性がより明確になった。この点を中心に、理論をサポートするその他いくつかの実証分析と、より現実的に日本の企業データ・マクロデータにフィットさせるモデルのカリブレーションを追加的に実施した。結果として、最適なインフレ率は、研究開発投資への影響を無視した場合よりも高くなることを示した。これらの結果をまとめた論文を国際学術誌に投稿済みである。第二に、特許データから抽出される企業間の技術的距離の時間を通じた動きを再現する研究開発プロジェクト選択のモデルを構築した。この枠組みは、ミクロ的な企業の研究開発の意思決定を通じてマクロ的な生産性成長への影響をシミュレーションするためのベースになる。例えば政策実験の一つとして、特許保護を強めることによりマクロ的な研究開発投資が減少するケースを示した。当初の計画から大きく外れることなく、概ね順調に研究の遂行ができている。本研究で明らかにしたインフレの成長促進効果は、逆に言えば持続的な低インフレがスムーズな企業淘汰や資源再配分を阻害し、経済成長を抑制することを意味する。また、これまでに得た結果は、経済の長期的な停滞から抜け出すためには、企業の研究開発が重要な役割を果たすが、単に研究開発投資の総量を高めるだけでは十分ではなく、研究開発の質も重要であることも示唆している。したがって、質の高い研究開発プロジェクトを遂行できる企業が市場で順当に生き残り、資源が効率的に活用される環境を整えることが、政策目標になる。本研究では若干のインフレ率がある程度自動的にそれに貢献することを新たに示したが、インフレ率は自在にコントロールできるわけではない。そこで、インフレ目標を追求すると同時に、ゼロインフレやデフレ下であっても研究開発能力を軸とした企業淘汰を促す政策を考える必要があるだろう。本研究の第二の取り組みは、企業の研究開発行動に直接働きかける特許政策等の効果を定量的に見出すことを目的としている。現状では、モデルのカリブレーションを十分に行っていないので、最終年度を通じて、現実のデータに即したパラメーターの探索を行い、その上で政策効果の仮想実験を行う

We construct a new method to describe firm distributions within technology fields and the dynamic behavior of these distributions. To locate firms on a technology space, we apply multidimensional scaling for the inter-firm technological dissimilarity matrices that are computed from patent citation overlaps among firms using the NBER US patent dataset. Our estimated firm distributions show increasing trends in technological distance and polarization on average, where we follow Duclos and et al. (2004) to measure polarization. We construct a model of inter-group competition in which polarization stimulates R&D incentives. The model fits data before the major patent reform in the United States in 1980s and polarization increases citation-weighted number of patent applications. After about 1990, the impact of polarization is reversed

This study examines the behaviors of firm-level volatility over business cycles, measured by real sales growth. Japanese firm-level data show that their volatility is countercyclical, whereas it is procyclical among the United States firms. We formulate a theoretical model that accounts for the opposite cyclical behaviors. The key driving factor behind the relationship is the relative magnitude of the fixed and marginal costs of bankruptcy. This study also examines the welfare and policy implication about the optimal bankruptcy cost structure

This research project built a theory that explains firm-level uncertainty, which is not aggregate but idiosyncratic, stimulates economic growth through accumulation of knowledge to reduce uncertainty. A surge in firm-level uncertainty surely brings a negative impact on the economy at least in the short run. However, the long-run impact turns out positive. I examined this model empirically using the firm-level data in the United States. Besides, I looked into the mechanism that generates relationship between firm-level uncertainty and macroeconomic fluctuation, based on the observed data in Japan and the United States. Firm-level uncertainty is procyclical in the United States on one hand, and it is countercyclical in Japan on the other. The model I built consistently explains this opposite tendency in cyclicality

研究開発の成果は、優れた研究スキルが優れた問題設定に出会ったときに最大化される。本研究では、企業が研究開発プロジェクトを決定し、雇用された研究者がそれに関与する状況を考え、米国特許データを用いて研究開発成果を企業と研究者の能力に分解した。その結果、良い研究者が良い企業に雇用される正相関マッチングが観察されるが、同時に正相関の程度はそれほど強くはないことも見出された。これは、研究者のミスアロケーションを示唆している。強制的に1の相関を持つように研究者と企業を再配置するシミュレーションによれば、総イノベーションは10-15%程度改善される余地があることが分かった。

Limit pricing by technologically-leading firms is often assumed in Schumpeterian growth models. However firms have an incentive to stay in the market even with a negative flow profit when continuing business will lead to future profits. This situation typically occurs in the model of Klette and Kortum (2004), in which holding a product line opens a new opportunity for successive R&D. We modify the Klette-Kortum model by introducing limit pricing based not on flow profit but on product value. The new pricing strategy can generate a drastic change because low quality innovations tend to be blocked to enter markets by incumbents. Applying it to the calibrated model in Lentz and Mortensen (2008), we show that the economy grows faster with higher welfare than the original model, and there is only tiny selection effect among observed entrant cohorts.

Responding to increasing attention to the distributional aspects of monetary policy, we investigate reallocation among heterogeneous firms triggered by nominal growth. Japanese firm-level data show that large firms tend to invest more in R&D and grow faster than small firms under higher inflation. We then construct a model that introduces nominal rigidity due to menu costs into R&D-driven endogenous growth with heterogeneous firms. The model shows that high nominal growth leads to an increase in the market share of innovative firms because menu-cost burdens are relatively heavier for less innovative firms. This reallocation effect leads to heavier tail of firm size distribution and yields a positive effect of monetary expansion on both real growth and welfare.

　マクロ的な経済成長を維持するには、持続的な技術進歩が不可欠である。本研究は、仮想的な技術空間における企業の戦略的立地と、イノベーション成果の関係に基づいて、ミクロ・マクロ両面から見て望ましイノベーション政策のあり方を探る試みである。　研究の第一段階では、企業が取得した特許データから抽出した企業間の技術的な距離を用いて、実際の技術空間上の企業立地の変化を追跡した。データから推計された移動距離や、移動先における企業集積状況など、立地が変化した時の特徴と、その後の各企業の特許申請状況を観察した。　研究の第二段階では、企業の技術立地モデルを作ってシミュレーションを行った。このモデルが有用であるのは、政策等の変化が引き起こす企業の技術的立地の内生的な変化を明示的に考慮した上で、影響を把握できる点にある。論文では、移動距離等の基本的な特性をモデルが再現できることを示した上で、特許保護を政策的に強めることで技術的距離が全体的に広がるように立地の変化が生じ、結果として特許保護のイノベーション促進効果を抑制することを示した。

We investigate the relationship between location choices of firms in a technology space and innovations at the firm and technological category levels. We estimate firm distribution in a technology space with patent citation overlaps and trace the locational changes of each firm. We find that a firm generates more quality-adjusted patents if it moves less in the technology space it belongs, the average distance to other firms is smaller, and technology is less accumulated around that location. At the technological category level, patent productivity tends to be high with low average moving distance but high standard deviation of it, low average distance between firms, and high entry rate. We then develop an agent-based model that generates dynamic behaviors of firms in a technology space. In the model, a firm sequentially chooses its location to maximize firm value conditional on the location profile of other firms minus the cost of moving. The firm value depends on knowledge spillover and market competition, where those factors are related to technological distances. With agent-based simulation, we analyze the impacts of regulation shifts such as patent protection policy and R&D subsidy.