In 2028, the median person on Earth will live on more than $10 a day for the first time in history (figures adjusted for inflation and for differences in purchasing power across countries). In the last decade alone, the share of people above this threshold has risen from 41.3% in 2016 (3.11 billion) to 48.7% in 2026 (4.03 billion). Think about that for a second: we have pushed nearly 900 million people over this threshold in ten years, around 90 million people a year (slightly above the population of Turkey). At the very bottom, we have also seen progress, though slower. In 2016, 12.6% of the world lived below $3 a day (947 million people). In 2026, the figure fell to 10.0% (826 million). This fall is harder to achieve because the poorest countries also have fast population growth. As fertility falls there, and I think it is already falling, we will cut poverty much faster. You are probably thinking that $10 a day is not a demanding threshold. True. But in 1990, yesterday in historical terms, only 1.42 billion people lived above it. And this is not just China: 2.6 billion people have crossed the $10 line. On the other hand, in 1990, 2.20 billion people lived below $3 a day. I checked these figures today because I start teaching Global Economic History at Penn this Wednesday, and I wanted to update the numbers I use. As Joel Mokyr instructs us: “The responsibility of economic historians is to remind the world what things were like before 1800. Growth was imperceptibly slow, and the vast bulk of the population was so poor that a harvest failure would kill millions. Almost half the babies born died before reaching age 5, and those who made it to adulthood were often stunted, ill and illiterate.” (“What Today's Economic Gloomsayers Are Missing,” 2014.) This will be my first lesson to the students on Wednesday: we live in times of historically unprecedented prosperity, and, by and large, things are getting much better every year.

A young person asked me today for a few papers that would be great to read early on in one’s career. Here is a list I came up with (I posted a shorter list earlier in reply to a comment). There are many other great papers (and I apologize if I didn’t include yours), but my goal was to focus on papers that a 21-year-old undergrad would enjoy a lot. A paper on the asymptotic properties of the bootstrap or on some subtle point about New Keynesian models, as important as it might be, is not what I am looking for. Also, of course, the list reflects my deeply biased taste. So, feel free to add in the comment section other papers you love! Philippe Aghion and Peter Howitt (1992), “A Model of Growth Through Creative Destruction,” Econometrica. George A. Akerlof (1970), “The Market for ‘Lemons’: Quality Uncertainty and the Market Mechanism,” Quarterly Journal of Economics. Armen A. Alchian (1950), “Uncertainty, Evolution, and Economic Theory,” Journal of Political Economy. William J. Baumol (1967), “Macroeconomics of Unbalanced Growth: The Anatomy of Urban Crisis,” American Economic Review. Gary S. Becker (1973), “A Theory of Marriage: Part I,” Journal of Political Economy. Douglas W. Diamond and Philip H. Dybvig (1983), “Bank Runs, Deposit Insurance, and Liquidity,” Journal of Political Economy. Xavier Gabaix (1999), “Zipf’s Law for Cities: An Explanation,” Quarterly Journal of Economics. Xavier Gabaix and Augustin Landier (2008), “Why Has CEO Pay Increased So Much?,” Quarterly Journal of Economics. Luis Garicano (2000), “Hierarchies and the Organization of Knowledge in Production,” Journal of Political Economy. Edward L. Glaeser, Bruce Sacerdote and José A. Scheinkman (1996), “Crime and Social Interactions,” Quarterly Journal of Economics. Sanford J. Grossman and Joseph E. Stiglitz (1980), “On the Impossibility of Informationally Efficient Markets,” American Economic Review. Oliver Hart and John Moore (1990), “Property Rights and the Nature of the Firm,” Journal of Political Economy. Friedrich A. Hayek (1945), “The Use of Knowledge in Society, American Economic Review. Bengt Holmström (1979), “Moral Hazard and Observability,” Bell Journal of Economics. Charles I. Jones (1995), “R&D-Based Models of Economic Growth,” Journal of Political Economy. Charles I. Jones (2005), “The Shape of Production Functions and the Direction of Technical Change,” Quarterly Journal of Economics. Michael Kremer (1993), “Population Growth and Technological Change: One Million B.C. to 1990,” Quarterly Journal of Economics. Michael Kremer (1993), “The O-Ring Theory of Economic Development,” Quarterly Journal of Economics. Paul Krugman (1991), “Increasing Returns and Economic Geography,” Journal of Political Economy. Robert E. Lucas, Jr. (1978), “On the Size Distribution of Business Firms,” Bell Journal of Economics. Kevin M. Murphy, Andrei Shleifer and Robert W. Vishny (1989), “Industrialization and the Big Push,” Journal of Political Economy. Paul M. Romer (1990), “Endogenous Technological Change,” Journal of Political Economy. Sherwin Rosen (1981), “The Economics of Superstars,” American Economic Review. Alvin E. Roth (2007), “Repugnance as a Constraint on Markets,” Journal of Economic Perspectives. Thomas C. Schelling (1971), “Dynamic Models of Segregation,” Journal of Mathematical Sociology. Andrei Shleifer and Robert W. Vishny (1993), “Corruption,” Quarterly Journal of Economics. Michael Spence (1973), “Job Market Signaling,” Quarterly Journal of Economics. Robert M. Townsend (1979), “Optimal Contracts and Competitive Markets with Costly State Verification,” Journal of Economic Theory. Martin L. Weitzman (1974), “Prices vs. Quantities,” Review of Economic Studies.