著者
ヨンテル トーマス
出版者
GRIPS Policy Research Center
雑誌
GRIPS Discussion Papers
巻号頁・発行日
vol.20-05, 2020-07

本稿のねらいは第一に、スウェーデンがなぜ、核兵器開発計画を始動させ、莫大な投資を何年も続けたのちに同計画を棚上げしたかを説明することである 。二つ目の、より重要なねらいは、核開発逆転を決める過程で、スウェーデン政府が、核拡散を防止する国際的な法的枠組みを作り出すことに、いかに多くの政治的エネルギーを注いだかを概説することである。スウェーデンは、1950 年代には核開発計画を持っていた。それは、核兵器開発と、原子力発電の双方の目標を、追求しようとするものであった。しかし、1960 年代終盤になると、核兵器の持つ意味が、全く変わってしまい、その結果としてスウェーデンの外交目標も、大きく転換することになった。1970 年までにスウェーデンがNPT を署名、批准したことは、理論上も実際上も、安全保障の概念が大きく変化し、核兵器が防衛と抑止の手段として見られていた状況から、国際安全保障とスウェーデンの国家としての生存への脅威として認識される状態に変化したことを示していた。The purpose of this paper is twofold. The first aim is to explain why Sweden embarked on a nuclear weapon program and why it was shelved after many years of heavy investments. The second, and even more important, aim is to outline the nuclear reversal process in which the Swedish government invested much political will into creating an international legal framework for preventing the spread of nuclear weapons. In the 1950s, Sweden had a national nuclear weapons development program. This program aimed to combine the double objectives of nuclear weapons acquirement and civilian nuclear power production. But by late 1960s, the meaning of the nuclear weapons had changed drastically, and the foreign policy objectives of Sweden changed accordingly. The signing and later the ratification of the NPT in 1970 by the Swedish government meant both in theory and practice that the concept of security had undergone a significant change, from a situation where nuclear weapons where seen as tools for protection and deterrence to circumstances that considered them as threats to international security and Sweden’s own survival as a nation.
著者
土谷 隆
出版者
GRIPS Policy Research Center
雑誌
GRIPS Discussion Papers
巻号頁・発行日
vol.20-04, 2020-05

1. 本研究では,東京都,大阪府,神奈川県の3自治体を取り上げ,簡単な感染症数理モデルをあてはめて種々のデータと整合性のある形で新型コロナウイルス感染症の感染実態を説明することを試みた.項目4から8がモデルによる解析の主たる結果である.2. 解析に用いるモデルはSIRモデルの単純な一変種で,未感染者・感染者・免疫保持者の割合の時間的変化を記述する.感染者は感染後一定期間(15日間) は他人に感染させる力があり,その後免疫保持者となる.感染者が感染力を持つ期間の感染力は(感染力パラメータβ) × (その時点での未感染者率) である.自粛や緊急事態宣言等の影響を,βの日毎の変化としてモデル化した.モデル自身はその考え方も記述も高等学校の数学の範疇で理解できるものである.3. 解析に用いたデータは下記の通りである.(a) 各自治体によって発表されている日ごとのPCR検査の陽性者数,(b) 厚生労働省新型コロナウイルス感染症対策専門家会議より2020年5月1日に発表された,東京都における日ごとの発症数(のグラフ),(c) 東京大学(2020年5月15日プレスリリース) と大阪市立大学(2020年5月1日プレスリリース) から発表された抗体検査の結果.4. 本感染症の実際の新規感染者数は,各自治体が把握している新規陽性者数の20倍程度はいる可能性があることが判明した.おそらくはこれらの感染者は,罹患中は感染源となるにもかかわらず,本人自身は未発症かごく軽症に終わり,自治体がその実態,感染プロセスを遅滞なく把握することは困難であると考えられる.仮に,発症者よりも感染力が弱いとしても,これらの未把握感染者は人数的には発症者の20倍程度おり,自由に活動し続けるため,感染が拡大していく上で主要な役割を果たしている可能性もある.したがって,ウイルス根絶のためには,行政が把握している新規陽性者が0となっただけでは不十分で,その状態をそれなりの期間継続する必要がある.5. 東京都において,5月25日に緊急事態宣言の解除が行われた.仮に3週間前後かけて3月26日以前のレベルの社会・経済活動に戻し,そのまま活動を続けると,7月上旬から中旬には感染者が急増する.さらに,仮に,それをそのまま放置すると,10月中旬にピークを迎える大流行となり,12月初旬には収束する.都民の88%が罹患し,36万人が発症し,7万2千人が重症化する.ピーク時には(現在の行政的意味で)1万7千人強の陽性者が1日に発生すると予測される.(これは,あくまでモデルによる試算である.実際には,今回すでに行われたような適切な活動制限・自粛を行うことによって回避可能である.西浦による4月15日の全国についての予測とオーダー的には合致している.)6. 直近の戦略について述べると,6月30日まで緊急事態宣言解除を延期して,その後比較的早く3月下旬のレベルまで社会活動を戻す方が,現行の解除戦略よりも,第2波が起こるまでにより長期間の活動が可能となるだけではなく,クラスター対策がより有効なレベルまでウイルス感染者が減少しうる点で,活動制限延長の損失を補って社会的には利得が大きいと考える.現行の戦略は,ウイルスが減少しきっていないうちに社会・経済活動を戻すため,最悪の場合には6月中に感染者が再増加し,再び行動制限や自粛をしなくてはいけなくなる可能性がある.7. 現行のシステムにおいても,ウイルス感染拡大を抑えるという立場だけからだけであれば,社会・経済活動を2ヶ月の活動期間と3ヶ月の活動制限期間を繰り返す形で,最大1日100人程度の(行政的意味での) 陽性者発生に抑え,周期的に持続していくことは可能であると思われる.(過去4ヶ月の内2月,3月を活動期間,4月,5月を活動制限期間として,仮にさらにもう一月,ウイルス感染鎮静化のため,6月までを活動制限期間としてみれば良い.) ただし,これでは経済的に持続可能とは限らないので,いろいろな工夫をして,3ヶ月の活動期間と1-2ヶ月の活動制限期間を繰り返す形にできるようにすることが,まずは,一つの現実的社会的目標として考えられる.8. 大規模な抗体検査,PCR検査, ICTの活用等,ウイルスの感染実態をつかむ継続的なサーベランスによる予測精度向上と社会全体での情報共有が重要である.9. なお,筆者は統計数理や数理工学の研究者ではあるが,感染症の数理モデルの専門家ではない.流行の態様と行く末を定量的に理解することを目的として,公開されているデータと素朴な数理モデルのみを利用して何ができるか,非力ながらも自分なりに真剣に考えてまとめたものが本小論である.モデルの帰結として若干の予測なども行っているが,これを読まれる方は,書かれている予測結果を鵜呑みにすることはせず,自身の責任で,検討材料の一つとしていただければ幸いである.モデルの検証に必要なことはすべて小論内に書かれている.なお,本小論の結果や考察はあくまで筆者個人の意見として発信されるものであり,筆者の所属大学の公式見解とは無関係である.
著者
川嶋 周一
出版者
GRIPS Policy Research Center
雑誌
GRIPS Discussion Papers
巻号頁・発行日
vol.16-17, 2016-10

本稿は、1955 年から 57 年にかけて交渉が行われ、58 年 1 月1 日に成立した欧州原子力共同体(以下、ユーラトム)がどのように成立し、そして機能していったのかを、ユーラトムが 50 年代から 60 年代にかけて確立していったグローバルな核秩序の中にどのように位置づけられるのか念頭に置きながら、考察するものである。ユーラトムは、現在の欧州連合(EU)の前身を構成する共同体の一つであり、現在でも一定の役割を果たしている。しかし、ユーラトムの双子として生まれた共同市場の欧州経済共同体(EEC)がその後EU につながる土台を提供するほどの成功を収めたのとは対照的に、原子力共同体は急速にその存在意義を失い、そしてほぼ忘れられた共同体となった。ユーラトムとは何だったのか。本稿は、欧州各国の未公刊史料を用いて、ユーラトムをヨーロッパ統合というよりもむしろ、50 年代の後半から 60 年代にかけて形成されていく、核エネルギーの平和利用レジームや北大西洋条約機構(NATO)を含めたより広いグローバルな核秩序の中に位置付けようとする。その際、ユーラトムは、ヨーロッパがアメリカに対する協調と自立を求める相矛盾する狭間の中で成立した、ある種のエアポケットであるさまが描かれるであろう。
著者
SAPKOTA Chandan WIE Dainn
出版者
GRIPS Policy Research Center
雑誌
GRIPS Discussion Papers
巻号頁・発行日
vol.19-28, 2019-12

Male outmigration is rapidly increasing in Nepal, leading the amount of remittance inflows to exceed 20% of GDP in 2011. This article examines the impact of male outmigration on women’s empowerment, which is relatively undocumented in the literature. We employ rainfall and an ethnicity-specific migration network as our instruments to address endogeneity in male outmigration. Our empirical evidence shows that married women in households with male outmigrants are less likely to be in polygamous relationships and are more likely to have the final say on their own health issues. However, further investigation demonstrates that these women are less likely to have freedom to visit their family or relatives, which is probably due to increased cohabitation with their parents-in-law.
著者
XING Yuqing
出版者
GRIPS Policy Research Center
雑誌
GRIPS Discussion Papers
巻号頁・発行日
vol.19-14, 2019-08

Global Value chains (GVC) provide a new channel of innovation for firms participating in value chains or utilizing the value chain strategy to grow. Upgrading to high value added segments of GVCs step by step is a linear model of innovation. Our analysis on the Chinese firms involved in the value chain of the iPhone shows that the Chinese mobile industry has climbed up ladders of the iPhone value chain and performed relatively sophisticated tasks beyond simple assembly. In addition, by examining foreign value added and technology embedded in the smartphones of OPPO, Xiaomi and Huawei, we argue the Chinese smartphone vendors primarily follow a non-linear model of innovation, jumping directly to brand development before acquiring sufficient technology capacity. They have been focusing on incremental innovations and product differentiation by taking advantage of available technology platforms. The value chain strategy enabled them to overcome technology deficiency effectively and opened a short-cut to catch-up foreign rivals and evolve into leading smartphone makers in both domestic and foreign markets.
著者
岩間 陽子
出版者
GRIPS Policy Research Center
雑誌
GRIPS Discussion Papers
巻号頁・発行日
vol.16-19, 2016-10

西ドイツ初代首相であり、1949年から1963年まで在任したコンラート・アデナウアーは、西ドイツの核保有を志向していたと言われるが、その実態はそれほど単純ではなかった。アデナウアーは、1954年のパリ協定署名時に、ABC(核・生物・化学)兵器の自国領内での製造を行わない宣言をしており、政権中にこの枠組みからはみ出すことはなかった。しかし、その範囲内で、西ドイツを核抑止の時代に適応させていった。まず、在独米軍の核兵器持ち込みを、事前協議制度なしで認めた。また、NATOの核備蓄制度を利用して、西ドイツ連邦軍の核搭載可能兵器を装備し、戦時には、それまで米軍管理下にある核兵器(弾頭)の配備を受ける制度を始めた。NATOの枠内での多角的核戦力(MLF)にも前向きな姿勢を見せながら、アデナウアーは何らかの形の「ヨーロッパ・オプション」に最後までこだわり続けた。それは、彼が米ソに大国のみが核を持つ世界では、ヨーロッパが見合うからの運命を決定する能力を失い、場合によっては超大国の取引対象となることを恐れたからであった。しかし、仏独エリゼー条約に対するアメリカの反応は、そのような道が非常に困難であることを示していた。Konrad Adenauer, the first West German Chancellor who was in office from 1949 to 1963, is said to have sought nuclear weapons for his country. But the truth is not that simple. Adenauer had renounced production of ABC weapons at the time of the signing of the Paris Treaties in 1954, and he never stepped out of this pledge. Instead, he adjusted his country to the nuclear age within that limit. First he allowed the American troops in West Germany to bring in nuclear weapons almost without any system of prior consultation. Next he put his country into the NATO nuclear stockpile system, by equipping the West German Bundeswehr with nuclear capable weapons. The nuclear weapons(warheads) to these weapons were usually under the control of American troops, and were passed onto the Bundeswehr at wartime. He also responded positively to the NATO multilateral force (MLF) plans, but also never ceased to look for an ‘European option.’ The reason for this was that he thought in a world in which only the US and USSR possessed nuclear weapons, Europe will no longer possess the ability to decide its own fate, and may become an object of deals between the two superpowers. But the American reaction to the Franco-German Elysée Treaty showed how difficult such an option was.
著者
MENG Xin YAMAUCHI Chikako
出版者
GRIPS Policy Research Center
雑誌
GRIPS Discussion Papers
巻号頁・発行日
vol.15-07, 2015-06

In the past 15 years, around 160 million Chinese rural workers migrated to cities for work. Because of restrictions on migrant access to local health and education system, many migrant children are left-behind in rural villages and growing up without parental care. This paper examines how parental migration affects children's health and education outcomes in the long run. Using the Rural-Urban Migration Survey in China (RUMiC) data, we measure the share of children's lifetime during which parents were away from home. We instrument this measure of parental absence with weather changes in their home villages when parents were aged 16-25, or when they were most likely to initiate migration. Results show a sizable adverse impact of exposure to parental migration on the health and education outcomes of children, in particular boys. We also find that what the literature has always done (using contemporaneous measure for parental migration) is likely to underestimate the effect of exposure to parental migration on children's outcomes.
著者
MASUDA Kazuya YAMAUCHI Chikako
出版者
GRIPS Policy Research Center
雑誌
GRIPS Discussion Papers
巻号頁・発行日
vol.17-01, 2017-04

Early pregnancy poses serious medical risk and economic burden to mother and neonatal children. While Economics literature generally explains negative relationship between female schooling and early fertility, it remains unclear whether this reflects a causal relationship. To fill in such a gap in literature, this paper examines the impact of female education on adolescent fertility, health investment behavior and the health status of their children in Uganda, focusing on the fully treated cohorts whose fees were abolished by Universal Primary Education policy (UPE) just before they entered schools. Education is instrumented by the interaction between across-cohorts differences in exposure to UPE and the differences in its effective benefits across districts with varying pre-program rates of completing primary education. We show that attending an additional year of schooling reduces the probability of marriage and that of giving birth before age 18 by 7.0-7.2 percentage points. Among those who become mothers, educated women use maternal care and infant immunization more often, and had lower probability that their child dies before 12 months after the birth. These results indicate that promoting the access to primary education among girls is an effective program to reduce adolescent pregnancy. It also shows the important role of maternal education in breaking the cycle of intergenerational transmission of the poor health in least eveloping countries by reducing child mortality. This in turn underscores the importance of considering the widespread benefits of female education in shaping the policy and nstitution influencing educational attainment.
著者
MUNRO Alistair
出版者
GRIPS Policy Research Center
雑誌
GRIPS Discussion Papers
巻号頁・発行日
vol.16-16, 2016-09

When the set of possible messages depends on the actual state of the world, optimal incentive schemes to control environmental problems may not always satisfy the revelation principle. As a result, in equilibrium some agents may send false messages, particularly when the information rents in the truth- telling scheme are high. I characterise optimal pollution regulation schemes and produce some numerical examples to show mechanisms which allow some dishonesty in equilibrium may frequently outperform truth-telling schemes.
著者
MANI Sunil
出版者
GRIPS Policy Research Center
雑誌
GRIPS Discussion Papers
巻号頁・発行日
vol.16-09, 2016-07

Right through her independence, India has been trying to achieve economic growth with technological self-reliance. In order to achieve this goal, the country has been adopting a mix of industrial and innovation policies. During the period up to and including the early 1990s, the state attempted to give shape to this goal by intervening directly by generating a whole host of industrial technologies through state-owned undertakings and other public research institutes. During the period since the 1990s, coinciding with the economic liberalization policies the state has replaced this with incentivizing the innovation system of the country. This is because the state wants the private sector enterprises to be at the core of the innovation system. Key to incentivizing the private sector was two specific policies, namely the R&D tax policy and the policy on Intellectual Property Rights. The paper undertakes a critical review of the very recent changes to these two policy instruments.
著者
YAMAZAKI Akio
出版者
GRIPS Policy Research Center
雑誌
GRIPS Discussion Papers
巻号頁・発行日
vol.19-32, 2020-02

This paper investigates how environmental taxes affect manufacturing productivity by examining British Columbia’s revenue-neutral carbon tax. I develop a new hypothesis, the “Productivity Dividend Hypothesis,” to show that environmental taxes can positively affect productivity by recycling tax revenues to reduce corporate income taxes. This revenue-recycling increases investment and could raise productivity more than environmental taxes lower productivity by diverting resources from production. I evaluate this hypothesis using detailed confidential plant-level data. I find that the carbon tax lowers productivity, although this is offset to some extent by the revenue-recycling. For some plants, the policy generates a net gain in productivity.
著者
春原 浩樹
出版者
GRIPS Policy Research Center
雑誌
GRIPS Discussion Papers
巻号頁・発行日
vol.17-18, 2018-03

ニュージーランドでは,改正後の「地震に弱い建築物制度」が2017年7月1日に施行された.本研究では,ニュージーランドと日本の法令,両国政府発出文書その他の文献の調査,ニュージーランドのEPB登録簿及び日本の所管行政庁から公表された耐震診断結果のデータの整理・分析等を通じて同制度の内容,適用の現状等を調査し,日本の耐震改修促進法による制度との比較分析を行った.その結果,同制度は,対象を限定して耐震化工事を義務付ける,耐震改修の目標性能レベルは現行基準の1/3とする,耐震診断結果は2段階の耐震等級を付して公表する,地震に弱い建築物であることを建築物に掲示させるなど,対象建築物,義務付けの内容,目標性能レベル,公表の内容や方法等の点で日本とは異なるアプローチを採用していることが分かった.New Zealand reviewed its policy for earthquake-prone buildings (EPB) and implemented a new system for managing EPBs as of July 1, 2017. This study explored the details and current state of its application and compared them to those of the similar program in Japan under the Act on Promotion of Seismic Retrofit of Buildings, through a survey of the respective laws and regulations of New Zealand and Japan, their publications, and other literature as well as analyses of the EPB register and by tabulating and analyzing the seismic assessment data of buildings published by the relevant agencies in Japan. It is concluded that the EPB program is taking an approach different from that of Japan in the applicable buildings, requirements, target performance, contents and methodology of disclosure. For instance, the New Zealand system requires seismic upgrading only on limited groups of buildings, a performance target of one third of the current level imposed on new construction, its seismic assessment to be published in two levels, and the building to be labeled as an EPB if so determined.
著者
XING Yuqing HE Yuzhen
出版者
GRIPS Policy Research Center
雑誌
GRIPS Discussion Papers
巻号頁・発行日
vol.18-09, 2018-09

In this paper, we evaluate the domestic value added of Chinese brand mobile phones using the teardown data of two sample phones: Xiaomi MIX 2 and OPPO R11s. For calculation of the distribution of value added by country, we adopt two benchmarks: production cost and retail price. In terms of the production cost of the sample phones, which consists of bill of materials, manufacturing cost and royalty, Chinese domestic value added embedded in the MIX 2 is 15.4% and 16.7% in the R11s. The teardown analysis reveals that no indigenous Chinese firms are involved in the manufacture of the printed circuit board assembly, which explains the relatively low Chinese domestic value added. Using retail price to measure total value added, we find that the domestic value added of the MIX 2 to be 41.7% while that of the R11s to be 45.3%. The cost of retail services and gross marginal profits contribute most to the increase, which implies that nurturing mobile phone brands has not only enabled the Chinese mobile phone industry to move up ladder of value chains, but also to improve domestic value added.
著者
ACHARYA Chakra Pani LEON-GONZALEZ Roberto
出版者
GRIPS Policy Research Center
雑誌
GRIPS Discussion Papers
巻号頁・発行日
vol.18-01, 2018-05

We examine the impact of remittances on economic growth using panel data (1975-2014) for 18 countries in Asia and Sub-Saharan Africa (SSA) that are similar in size and development level. We allow for heterogeneous production functions across countries and calculate the average marginal effects of remittances using the panel dynamic ordinary least squares estimator. The estimation results show that remittances increase growth significantly, especially through investments in human capital. In addition we find that: (i) remittances have a modest impact on growth when controlling for physical and human capital channels through which remittances potentially affect output growth; (ii) when we do not control for human capital the effect is larger regardless of the sub-samples considered − the elasticity of output with respect to remittances is 7.3 percent in the full sample, and 18.6 percent among Asian countries; (iii) remittances have a significant positive long-run effect on human capital formation regardless of the sub-samples considered but the effect on physical capital accumulation is significant only among middle income and Asian countries. The findings suggest that channeling the remittances towards investments in physical capital and adoption of new knowledge, skills and technology is crucial for high economic growth in low income countries.
著者
FUJIMOTO Junichi MUNAKATA Ko NAKAMURA Koji TERANISHI Yuki
出版者
GRIPS Policy Research Center
雑誌
GRIPS Discussion Papers
巻号頁・発行日
vol.16-30, 2017-02

To reveal a policy mandate for financial stability, we introduce a frictional credit market with a search and matching process into a standard New Keynesian model with nominal rigidities in the goods market, and then investigate optimal policy under financial frictions. We show that a second-order approximation of social welfare includes terms for credit, in addition to terms for inflation and consumption, so that any optimal policy must hold responsibility for financial and price stabilities. We highlight this issue by considering several tools for monetary and macroprudential policy. We find that optimal monetary policy requires keeping the credit market countercyclical against the real economy. Also, optimal macroprudential policy, which poses constraints on supply and demand sides of credit, reduces excessive variations in lending and contributes to both financial and price stabilities.
著者
FUJIMOTO Junichi LEE Junsang
出版者
GRIPS Policy Research Center
雑誌
GRIPS Discussion Papers
巻号頁・発行日
vol.16-15, 2016-09

This paper examines efficient risk sharing under limited commitment and searchfrictions. The model features a social planner and a continuum of risk-averseworkers, where the planner is able to provide consumption only to workers matchedwith the planner and faces an aggregate resource constraint, while workers can walkaway from the match in any period and search for a new match. The formation ofnew matches and the exogenous destruction of existing ones substantially expandthe set of feasible stationary allocations, providing a role for the social welfarefunction. In the benchmark case of the Benthamite social welfare function, wefind that the efficient stationary allocation exhibits novel consumption dynamics:Consumption begins at a relatively low level, converges toward a certain level whenthe participation constraint is slack, and jumps up when it binds. We then explorethe role of limited commitment in generating such rich consumption dynamics.
著者
HOSOE Nobuhiro
出版者
GRIPS Policy Research Center
雑誌
GRIPS Discussion Papers
巻号頁・発行日
vol.16-14, 2016-08

The impact of Brexit is investigated using two computable general equilibrium (CGE) models, featuring conventional constant-returns-to-scale (CRS) technology and increasing-returns-to-scale (IRS) technology with firm heterogeneity, à la Melitz. The imposition of trade barriers would trigger a significant contraction of the bilateral trade between the United Kingdom (UK) and the rest of the European Union (EU). While a CRS CGE model predicts that the trade barriers would benefit or only marginally harm the UK’s welfare, the IRS model predicts a larger loss through firm exit and loss of varieties, comparable to the expected saving of the UK’s contribution to the EU budget. Among the UK industries, the textiles and apparel, steel and metal, and automotive and transportation equipment sectors would suffer most severely from their sharp fall in exports.
著者
CHEY Hyoung-kyu LI Yu Wai Vic
出版者
GRIPS Policy Research Center
雑誌
GRIPS Discussion Papers
巻号頁・発行日
vol.15-23, 2016-02

Despite the central bank’s crucial position in the economy, as the issuer of the currency and the body responsible for monetary policy, its preferences regarding currency internationalization and its roles in that process have rarely been analyzed in the literature. This study attempts to fill this critical gap by bringing the central bank into the study of currency internationalization. A conventional understanding of currency internationalization is that it tends to reduce monetary policy autonomy, which implies a natural tendency of the central bank to oppose it. This study shows, however, that currency internationalization does not necessarily reduce the central bank’s monetary policy autonomy, and may in fact even strengthen it. It shows that currency internationalization is likely to strengthen the central bank’s independence as well. Based on these findings, this study argues that a central bank with weak monetary policy autonomy and low independence is more likely to support the internationalization of its country’s currency. These arguments are empirically verified, mainly by in-depth analysis of the case of the People’s Bank of China and the renminbi.
著者
LOPEZ Maria Claudia MUNRO Alistair TARAZONA-GOMEZ Marcela
出版者
GRIPS Policy Research Center
雑誌
GRIPS Discussion Papers
巻号頁・発行日
vol.15-10, 2015-07

A recurring and puzzling pattern with experiments on intra-household behaviour is the common failure of couples to attain the cooperative solution. Using married couples from a low income area of Bogota, Colombia we conduct an experiment that raises the salience of the family vis-à-vis outsiders. In this experiment husbands and wives play a repeated voluntary contribution game. At the same time each participant plays an identical game with one stranger in the same session. When investments to the common pools are made from separate and non-fungible budgets, most subjects contribute more to the household pool than the stranger pool, but rarely contribute everything to the household even after repetition and opportunities for learning. Efficiency is not obtained. However, when subjects make contributions to the two games from a single budget many individuals converge rapidly on a strategy of investing everything in the household pool and contributing little to the pool with a stranger. Overall the amount invested in some pool rises. Our results are in line with games played with individuals in which in-group cooperation is higher when membership of the group is more salient. They suggest that strengthening family identity may raise intrahousehold cooperation, but at the expense of cooperation of interhousehold cooperation.
著者
阿久根 優子 細江 宣裕
出版者
GRIPS Policy Research Center
雑誌
GRIPS Discussion Papers
巻号頁・発行日
vol.19-05, 2019-06

独占的競争下の製品差別化を取り入れた枠組みは、おもに製造業について適用され、農業は製品差別化のない同質財部門として単純化して描写されることが多い。一方、農業経営や農業政策に関する分析では、製品差別化を通じて高付加価値化を図る、高い起業家精神や生産性を持つ一部の生産者に注目が集まる。現実はどちらに近いのであろうか。本研究では、『農家経営統計調査』の個票データを用いて、農家の全要素生産性とその分布を導き、合わせて、Crozet and Koenig (2010)の手法を用いて、差別化財(バラエティ)間の代替の弾力性を推定する。分析の結果、施設野菜作や施設花卉作といった施設園芸関連、畑作や果樹作で、生産者間の異質性が相対的に高いことが確認された。製品差別化の程度は、畜産関連の営農類型で相対的に高い傾向にある。バラエティ間の代替の弾力性は大きくても3程度であり、製造業について得られる弾力性と大きく異なるものではないことがわかった。