ウィスコンシン最高裁はCOVID-19疫病を再発させたか? 自然実験の実証結果

というNBER論文が上がっている。原題は「Did the Wisconsin Supreme Court Restart a COVID-19 Epidemic? Evidence from a Natural Experiment」で、著者はDhaval M. Dave(ベントレー大)、Andrew I. Friedson(コロラドデンバー校)、Kyutaro Matsuzawa(サンディエゴ州立大)、Drew McNichols(サンディエゴ大)、Joseph J. Sabia(サンディエゴ州立大)。

Both the White House and state governors have explicitly linked thresholds of reduced COVID-19 case growth to the lifting of statewide shelter-in-place orders (SIPOs). This “hardwired” policy endogeneity creates empirical challenges in credibly isolating the causal effect of lifting a statewide SIPO on COVID-19-related health. To break this simultaneity problem, the current study exploits a unique natural experiment generated by a Wisconsin Supreme Court decision. On May 13, 2020, the Wisconsin Supreme Court abolished the state’s “Safer at Home” order, ruling that the Wisconsin Department of Health Services unconstitutionally usurped legislative authority to review COVID-19 regulations. We capitalize on this sudden, dramatic, and largely unanticipated termination of a statewide SIPO to estimate its effect on social distancing and COVID-19 case growth. Using a synthetic control design, we find no evidence that the repeal of the state SIPO impacted social distancing, COVID-19 cases, or COVID-19-related mortality during the fortnight following enactment. Estimated effects were economically small and nowhere near statistically different from zero. We conclude that the impact of shelter-in-place orders is likely not symmetric across enactment and lifting of the orders.



というNBER論文をルイジ・ジンガレスらが上げている。原題は「Civic Capital and Social Distancing during the Covid-19 Pandemic」で、著者はJohn M. Barrios(シカゴ大)、Efraim Benmelech(ノースウエスタン大)、Yael V. Hochberg(ライス大)、Paola Sapienza(ノースウエスタン大)、Luigi Zingales(シカゴ大)。

The success of non-pharmaceutical interventions to contain pandemics often depends greatly upon voluntary compliance with government guidelines. What explains variation in voluntary compliance? Using mobile phone and survey data, we show that during the early phases of COVID-19, voluntary social distancing was higher when individuals exhibit a higher sense of civic duty. This is true for U.S. individuals, U.S. counties, and European regions. We also show that after U.S. states began re-opening, social distancing remained more prevalent in high civic capital counties. Our evidence points to the importance of civic capital in designing public policy responses to pandemics.
パンデミック封じ込めの非医薬的措置の成功は、政府の指針の自主的な遵守によるところが大きい。自主的な遵守のばらつきを説明するものは何だろうか? 携帯電話データと調査データを用いて我々は、COVID-19の初期の局面では、人々の市民の義務への意識が高いほど、自主的な社会的距離がより取られたことを示す。これは米国の個人、米国の各郡、および欧州地域において成立した。我々はまた、米国の各州が活動を再開し始めた時、市民資本の高い郡ほど社会的距離がより広範に維持されたことを示す。我々の実証結果は、パンデミックへの政策対応を設計するに当たっての市民資本の重要性を指し示している。



というNBER論文が上がっている。原題は「Estimating and Forecasting Disease Scenarios for COVID-19 with an SIR Model」で、著者はAndrew Atkeson(UCLA)、Karen Kopecky(アトランタ連銀)、Tao Zha(エモリー大)。

This paper presents a procedure for estimating and forecasting disease scenarios for COVID-19 using a structural SIR model of the pandemic. Our procedure combines the flexibility of noteworthy reduced-form approaches for estimating the progression of the COVID-19 pandemic to date with the benefits of a simple SIR structural model for interpreting these estimates and constructing forecast and counterfactual scenarios. We present forecast scenarios for a devastating second wave of the pandemic as well as for a long and slow continuation of current levels of infections and daily deaths. In our counterfactual scenarios, we find that there is no clear answer to the question of whether earlier mitigation measures would have reduced the long run cumulative death toll from this disease. In some cases, we find that it would have, but in other cases, we find the opposite — earlier mitigation would have led to a higher long-run death toll.







というNBER論文をロバート・ホールらが上げている*1。原題は「Trading Off Consumption and COVID-19 Deaths」で、著者はいずれもスタンフォード大のRobert E. Hall、Charles I. Jones、Peter J. Klenow。

This note develops a framework for thinking about the following question: What is the maximum amount of consumption that a utilitarian welfare function would be willing to trade off to avoid the deaths associated with the pandemic? The answer depends crucially on the mortality rate associated with the coronavirus. If the mortality rate averages 0.81%, taken from the Imperial College London study, our answer is 41% of one year's consumption. If the mortality rate instead averages 0.44% across age groups, our answer is 28%.
本稿は以下の疑問について考える枠組みを構築する:功利主義的厚生関数がパンデミックによる死を防ぐために進んで犠牲にする最大の消費額は幾らだろうか? その答えはコロナウイルスによる致死率に決定的に依拠している。もし致死率平均がインペリアルカレッジロンドンの研究が示す0.81%ならば、我々の回答は1年の消費の41%である。もし致死率の年齢層平均が0.44%ならば、我々の回答は28%である。

 α ≈ δ・v・LE

δ v=5 v=6 v=7
0.81% 58.7 70.5 82.2
0.44% 32.0 38.4 44.8


δ v=5 v=6 v=7
0.81% 37.0 41.3 45.1
0.44% 24.2 27.7 30.9




というNBER論文が上がっている。原題は「An Event Study of COVID-19 Central Bank Quantitative Easing in Advanced and Emerging Economies」で、著者はJonathan S. Hartley(ハーバード大)、Alessandro Rebucci(ジョンズ・ホプキンス大)。

Amid the COVID-19 outbreak and related expected economic downturn, many developed and emerging market central banks around the world engaged in new long-term asset purchase programs, or so-called quantitative easing (QE) interventions. This paper conducts an event-study analysis of 24 COVID-19 QE announcements made by 21 global central banks on their local 10-year government bond yields. We find that the average developed market QE announcement had a statistically significant -0.14% 1-day impact, which is slightly smaller than past interventions during the Great Recession era. In contrast, the average impact of emerging market QE announcements was significantly larger, averaging -0.28% and -0.43% over 1-day and 3-day windows, respectively. Across developed and emerging bond markets, we estimate an overall average 1-day impact of -0.23%. We also show that all 10-year government bond yields in our sample rose sharply in mid-March 2020, but fell substantially after the period of QE announcements that we study in the paper.


本ブログではUCLAのDavid BaqaeeとハーバードのEmmanuel Farhiのコンビのマクロ経済学の論文を何回か紹介してきたが(直近は4日エントリで紹介した他の共著者との再開シナリオ論文)、同コンビの表題のNBER論文が上がっている(原題は「Supply and Demand in Disaggregated Keynesian Economies with an Application to the Covid-19 Crisis」)。以下はその要旨。

We study the effects of supply and demand shocks in a general disaggregated model with multiple sectors, factors, and input-output linkages, as well as downward nominal wage rigidities and a zero lower bound constraint. In response to shocks, some sectors become tight and operate at full capacity while others become slack and under-utilize the resources available to them. We use the model to understand how the Covid-19 crisis, an omnibus of various supply and demand shocks, affects output, unemployment, and inflation. Throughout the analysis, we focus on the role of the production network and of the elasticities of substitution. We establish that under some conditions, the details of the production network can be summarized by simple sufficient statistics. We use these sufficient statistics to conduct global comparative statics, and illustrate the intuition for our results using a nonlinear ASAD representation of the model. Negative sectoral supply shocks and shocks to the sectoral composition of demand are necessarily stagflationary, whereas negative aggregate demand shocks are deflationary. The effects of the former are stronger and the effects of the latter are weaker with stronger complementarities in production and in consumption. These shocks interact and are amplified or mitigated through nonlinearities. We quantify our results using disaggregated data from the U.S.


When there are complementarities (θ < 1), the negative supply shock in one factor market causes the downward nominal wage rigidity to bind and triggers Keynesian unemployment in the other factor market. By contrast, with substitutability (θ ≥ 1), the downward nominal wage rigidity constraint does not bind in any of the two factor markets and the model behaves exactly like the neoclassical one.


As long as θ > 1, the second kink is below the AD curve, and so the equilibrium is the same as the neoclassical one, because the AS and AD intersect along the neoclassical portion of the AS curve. Intuitively, when θ > 1, no factor market becomes rigid and so downward nominal wage rigidity is never triggered. Once the elasticity of substitution has been lowered to θ = 1, the Cobb-Douglas case, the second kink exactly intersects the AD curve. As θ goes below one, the second kink moves above the AD curve, downward nominal wage rigidities are triggered, and the equilibrium has lower output and higher inflation than the neoclassical model. Finally, as θ goes to zero and we approach the Leontief case, the second kink point moves directly above the first kink point, and so the reduction in output in the neoclassical model and Keynesian model become the same again.

ここで1番目の屈曲点とはAS曲線が水平になる点(Y = L'f)、2番目の屈曲点とはAS曲線が垂直になる点である。


というNBER論文が上がっている。原題は「The Cost of Privacy: Welfare Effect of the Disclosure of COVID-19 Cases」で、著者はDavid O. Argente(ペンシルベニア州立大)、Chang-Tai Hsieh(シカゴ大)、Munseob Lee(UCサンディエゴ)。

South Korea publicly disclosed detailed location information of individuals that tested positive for COVID-19. We quantify the effect of public disclosure on the transmission of the virus and economic losses in Seoul. We use detailed foot-traffic data from South Korea's largest mobile phone company to document the change in the flows of people across neighborhoods in Seoul in response to information on the locations of positive cases. We analyze the effect of the change in commuting flows in a SIR meta-population model where the virus spreads due to these flows. We endogenize these flows in a model of urban neighborhoods where individuals commute across neighborhoods to access jobs and leisure opportunities. Relative to a scenario where no information is disclosed, the change in commuting patterns due to public disclosure lowers the number of cases by 400 thousand and the number of deaths by 13 thousand in Seoul over two years. Compared to a city-wide lock-down that results in the same number of cases over two years, the economic cost is 50% lower with full disclosure.