David Card, Joshua D. Angrist and Guido W. Imbens have made a career of studying unintended experiments — Mr. Card in labor economics and Mr. Angrist and Mr. Imbens in analyzing cause and effect.
On Monday, their work earned them the 2021 Nobel Memorial Prize in Economic Sciences.
All three winners are based in the United States. Mr. Card, who was born in Canada, works at the University of California, Berkeley. Mr. Angrist, born in the United States, is at M.I.T. and Mr. Imbens, born in the Netherlands, is at Stanford University.
“Uncovering causal relationships is a major challenge,” said Peter Fredriksson, chairman of the prize committee. “Sometimes, nature, or policy changes, provide situations that resemble randomized experiments. This year’s laureates have shown that such natural experiments help answer important questions for society.”
Mr. Card’s work has challenged conventional wisdom in labor economics — including the idea that higher minimum wages led to lower employment. He was a co-author of influential studies on that topic with Alan B. Krueger, who died in 2019, including one that used the natural geographical border between New Jersey and Pennsylvania to test the effect of a minimum wage change. Comparing outcomes between the states, the research found that employment at fast food restaurants was not affected by an increase in New Jersey’s minimum wage.
Mr. Angrist and Mr. Imbens have contributed to the way researchers think about and analyze natural experiments.
They showed that it is possible to identify a clear effect from an intervention in people’s behavior — like a subsidy that might encourage people to ride bicycles to work — even if a researcher cannot control who takes part in the experiment, and even if the impact varies across individuals. The pair also came up with a transparent framework for such research that has increased trust in it.
“The challenge, for me, has always been trying to understand, when people do empirical work, what exactly the methodological challenges are,” Mr. Imbens said, speaking to the announcement’s news conference via telephone.
Mr. Imbens said he was asleep when he received the call from the prize committee — around 2 a.m. — and was “absolutely stunned” to hear the news. He noted that Mr. Angrist was the best man at his wedding.
Two American economists affiliated with Stanford University, Paul R. Milgrom and Robert B. Wilson, won the 2020 Nobel in economics for improvements to auction theory. Abhijit Banerjee and Esther Duflo of M.I.T. and Michael Kremer of Harvard won in 2019 for their experiment-based research in development economics.
The award, formally called the Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel, has been given out since 1969.
Who are the other Nobel Prize winners in 2021?
The Nobel Prize in Physiology or Medicine was awarded jointly to David Julius and Ardem Patapoutian, who independently discovered key mechanisms of how people sense heat, cold, touch and their own bodily movements.
Syukuro Manabe, Klaus Hasselmann and Giorgio Parisi were recognized with the Nobel Prize in Physics for work that “laid the foundation of our knowledge of the Earth’s climate and how humanity influences it.”
The Nobel Prize in Chemistry went to Benjamin List and David W.C. MacMillan for their development of a new tool to build molecules, work that has spurred advances in pharmaceutical research and allowed scientists to construct catalysts with considerably less impact on the environment.
Abdulrazak Gurnah was awarded the Nobel Prize in Literature for “his uncompromising and compassionate penetration of the effects of colonialism and the fate of the refugee in the gulf between cultures and continents.”
Two journalists thousands of miles apart, Maria Ressa of the Philippines and Dmitri A. Muratov of Russia, were honored with the Nobel Peace Prize for their tireless efforts to hold the powerful to account.
Travelers flying Southwest Airlines over the weekend faced hundreds of canceled flights as well as frustrating delays, with the airline scrapping about a quarter of all its flights on Saturday and Sunday.
The airline canceled just over 800 flights on Saturday, or 24 percent of all its scheduled flights, according to FlightAware, a tracking service. By noon on Sunday, Southwest had already canceled over a thousand flights, or 28 percent of its schedule, with hundreds more delayed.
“We experienced weather challenges in our Florida airports at the beginning of the weekend, challenges that were compounded by unexpected air traffic control issues in the same region, triggering delays and prompting significant cancellations,” the airline said in a statement on Sunday. “We’ve continued diligent work throughout the weekend to reset our operation with a focus on getting aircraft and crews repositioned to take care of our customers.”
Southwest added that recovering from the disruption was more difficult than usual because it is operating fewer flights than before the pandemic, complicating efforts to reschedule passengers.
The latest James Bond spectacle, “No Time to Die,” gave Hollywood its third box office success in the span of a month.
But the pandemic-era box office is still extremely fragile, analysts say, and the only movies attracting sizable attention in cinemas are big-budget franchise films, Brooks Barnes reports in The New York Times. The audience for smaller dramas and comedies seems — at least for now — to be satisfied with home viewing, either buying films through video on demand or watching them on streaming services.
“Superhero, action and horror movies are performing well in theaters, particularly when they are offered exclusively and not simultaneously available to stream,” said David A. Gross, who runs Franchise Entertainment Research, a film consultancy.
“No Time to Die” gave Hollywood hope that the worst times of the pandemic are in the past. Billed as the 25th installment in the Bond franchise and with Daniel Craig in his fifth and final turn as 007, “No Time to Die” took in an estimated $56 million from 4,407 theaters in the United States and Canada, according to Comscore. In partial release overseas, the Bond film collected an additional $257 million, according to Metro-Goldwyn-Mayer and its overseas distribution partner, Universal Pictures International.