日期:2021/10/12

 

The 2021 Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel has been awarded with one half to David Card and the other half jointly to Joshua D. Angrist and Guido W. Imbens.

Nobel Prize in Economics 2021

 

Announcement of the Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel 2021 by Professor Göran K. Hansson, Secretary General of the Royal Swedish Academy of Sciences, on 11 October 2021.瑞典皇家科學院秘書長 Göran K. Hansson 教授於 2021 年 10 月 11 日宣布授予瑞典央行紀念阿爾弗雷德·諾貝爾 2021 年經濟學獎。

Natural experiments help answer important questions for society

This year’s Laureates – David Card, Joshua Angrist and Guido Imbens – have provided us with new insights about the labour market and shown what conclusions about cause and effect can be drawn from natural experiments. Their approach has spread to other fields and revolutionised empirical research.

Many of the big questions in the social sciences deal with cause and effect. How does immigration affect pay and employment levels? How does a longer education affect someone’s future income? These questions are difficult to answer because we have nothing to use as a comparison. We do not know what would have happened if there had been less immigration or if that person had not continued studying.

However, this year’s Laureates have shown that it is possible to answer these and similar questions using natural experiments. The key is to use situations in which chance events or policy changes result in groups of people being treated differently, in a way that resembles clinical trials in medicine.

Using natural experiments, David Card has analysed the labour market effects of minimum wages, immigration and education. His studies from the early 1990s challenged conventional wisdom, leading to new analyses and additional insights. The results showed, among other things, that increasing the minimum wage does not necessarily lead to fewer jobs. We now know that the incomes of people who were born in a country can benefit from new immigration, while people who immigrated at an earlier time risk being negatively affected. We have also realised that resources in schools are far more important for students’ future labour market success than was previously thought.

Data from a natural experiment are difficult to interpret, however. For example, extending compulsory education by a year for one group of students (but not another) will not affect everyone in that group in the same way. Some students would have kept studying anyway and, for them, the value of education is often not representative of the entire group. So, is it even possible to draw any conclusions about the effect of an extra year in school? In the mid-1990s, Joshua Angrist and Guido Imbens solved this methodological problem, demonstrating how precise conclusions about cause and effect can be drawn from natural experiments.

“Card’s studies of core questions for society and Angrist and Imbens’ methodological contributions have shown that natural experiments are a rich source of knowledge. Their research has substantially improved our ability to answer key causal questions, which has been of great benefit to society,” says Peter Fredriksson, chair of the Economic Sciences Prize Committee.

Illustrations

The illustrations are free to use for non-commercial purposes. Attribute ”© Johan Jarnestad/The Royal Swedish Academy of Sciences”

Illustration: Association between education and income (pdf)
Illustration: Years of education (pdf)
Illustration: Effect of increasing the minimum wage (pdf)
Illustration: Local average treatment effect (pdf)

Read more about this year’s prize

Popular science background: Natural experiments help answer important questions (pdf)
Scientific Background: Answering causal questions using observational data (pdf)

 

David Card, born 1956 in Guelph, Canada. Ph.D. 1983 from Princeton
University, USA. Class of 1950 Professor of Economics, University of
California, Berkeley, USA.

Joshua D. Angrist, born 1960 in Columbus, Ohio, USA. Ph.D. 1989 from
Princeton University, USA. Ford Professor of Economics, Massachusetts
Institute of Technology, Cambridge, USA.

Guido W. Imbens, born 1963 in Netherlands. Ph.D. 1991 from
Brown University, Providence, USA. The Applied Econometrics Professor
and Professor of Economics, Stanford University, USA.

 

Prize amount: 10 million Swedish kronor, with one half to David Card and the other half jointly to Joshua Angrist and Guido Imbens.
Further information: www.kva.se and www.nobelprize.org
Press contact: Eva Nevelius, Press Secretary, +46 70 878 67 63, eva.nevelius@kva.se
Experts: Peter Fredriksson, +46 76 806 70 80, peter.fredriksson@nek.uu.se, Eva Mörk, +46 70 952 51 30, eva.mork@nek.uu.se, Jakob Svensson, +46 70 177 67 17, jakob.svensson@iies.su.se, Committee for the Prize in Economic Sciences in Memory of Alfred Nobel

The Royal Swedish Academy of Sciences, founded in 1739, is an independent organisation whose overall objective is to promote the sciences and strengthen their influence in society. The Academy takes special responsibility for the natural sciences and mathematics, but endeavours to promote the exchange of ideas between various disciplines.

Nobel Prize® is a registered trademark of the Nobel Foundation.

 

自然實驗有助於回答社會的重要問題
今年的獲獎者——David Card、Joshua Angrist 和 Guido Imbens——為我們提供了關於勞動力市場的新見解，並展示了可以從自然實驗中得出關於因果關係的結論。他們的方法已經擴展到其他領域並徹底改變了實證研究。
社會科學中的許多重大問題都涉及因果關係。移民如何影響薪酬和就業水平？更長的教育如何影響某人未來的收入？這些問題很難回答，因為我們沒有什麼可用作比較的。我們不知道如果移民減少或者那個人沒有繼續學習會發生什麼。
然而，今年的獲獎者表明，可以使用自然實驗來回答這些和類似的問題。關鍵是利用偶然事件或政策變化導致人群受到不同對待的情況，以類似於醫學臨床試驗的方式。
David Card 使用自然實驗分析了最低工資、移民和教育對勞動力市場的影響。他從 1990 年代初期開始的研究挑戰了傳統智慧，帶來了新的分析和更多的見解。結果表明，除其他外，提高最低工資並不一定會導致工作崗位減少。我們現在知道，在一個國家出生的人的收入可以從新移民中受益，而較早移民的人則有可能受到負面影響。我們還意識到，學校資源對於學生未來勞動力市場的成功比以前想像的要重要得多。
然而，來自自然實驗的數據很難解釋。例如，將一組學生（但不是另一組）的義務教育延長一年不會以同樣的方式影響該組中的每個人。一些學生無論如何都會繼續學習，對他們來說，教育的價值往往不能代表整個群體。那麼，是否有可能得出關於多上一年學的影響的任何結論？在 1990 年代中期，Joshua Angrist 和 Guido Imbens 解決了這個方法論問題，展示瞭如何從自然實驗中得出關於因果關係的精確結論。
“卡德對社會核心問題的研究以及 Angrist 和 Imbens 的方法論貢獻表明，自然實驗是豐富的知識來源。他們的研究大大提高了我們回答關鍵因果問題的能力，這對社會大有裨益，”經濟科學獎委員會主席 Peter Fredriksson 說。
插圖
插圖可免費用於非商業目的。屬性“© Johan Jarnestad/瑞典皇家科學院”
插圖：教育與收入之間的關聯 (pdf)
插圖：受教育年限 (pdf)
插圖：提高最低工資的影響 (pdf)
插圖：局部平均處理效果 (pdf)
閱讀有關今年獎項的更多信息
科普背景：自然實驗有助於回答重要問題 (pdf)
科學背景：使用觀察數據回答因果問題 (pdf)
 
大衛·卡德，1956 年出生於加拿大圭爾夫。博士1983年來自普林斯頓
大學，美國。 1950級經濟學教授，大學
加利福尼亞州，伯克利，美國。
Joshua D. Angrist，1960 年出生於美國俄亥俄州哥倫布市。博士1989年起
美國普林斯頓大學。馬薩諸塞州福特經濟學教授
美國劍橋理工學院。
Guido W. Imbens，1963 年出生於荷蘭。博士1991年起
美國普羅維登斯布朗大學。應用計量經濟學教授
美國斯坦福大學經濟學教授。
 
獎金金額：1000萬瑞典克朗，一半給大衛·卡德，另一半共同給約書亞·安格里斯特和吉多·伊本斯。
更多信息：www.kva.se 和 www.nobelprize.org
新聞聯繫人：Eva Nevelius，新聞秘書，+46 70 878 67 63，eva.nevelius@kva.se
專家：Peter Fredriksson，+46 76 806 70 80，peter.fredriksson@nek.uu.se，Eva Mörk，+46 70 952 51 30，eva.mork@nek.uu.se，Jakob Svensson，+46 70 177 17, jakob.svensson@iies.su.se，紀念阿爾弗雷德·諾貝爾經濟學獎委員會
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