Category: Economics
AI and Marginal Revolutions in Wastewater Treatment
An interesting paper from French economists, including recent Nobelist Philippe Aghion, looks at the savings from a predictive machine-learning model applied to wastewater treatment:
This paper studies the environmental effects of a specialised AI aeration-control system deployed across French wastewater treatment plants operated by a global leader in water supply services. Exploiting quasi-experimental variation in both the timing of adoption and outages, we estimate the causal impact of AI on electricity use, carbon emissions, and energy expenditures. We find that full-time AI control reduces plants’ electricity consumption and carbon emissions by 5.4% and 6% respectively, and energy expenditures by 8.2%, resulting in negative abatement costs, while also improving water effluent quality. The additional electricity demand generated by AI models represents less than 1% of these savings. Beyond these effects, AI-equipped plants prove more resilient to high operational stress during extreme meteorological events and chemical pollutant peaks. They also improve load management by reallocating electricity consumption from peak to off-peak hours. Finally, we use the DICE model to assess the aggregate implications of our findings
in three diffusion scenarios. We find substantial global welfare gains from the CO2 reductions associated with this industrial AI use case.
One annoyance: The authors frame the paper as a contrast to worries about AI’s energy use and environmental impact. But those objections are almost entirely innumerate and pretextual and casting the paper as a rebuttal lends them more credibility than they deserve.
One note: Don’t misread the “less than 1%” line as being in the same units as the 5.4%, 6%, and 8.2% figures above it — it isn’t a comparable percentage-point offset. It means the AI system’s own electricity draw is a rounding error next to the savings it generates.
More generally, the effect of AI will be through many, many improvements of this nature.
Solve for the (Refine) equilibrium
We’re proud to announce that Refine has signed partnerships with two leading publishers in economics. Both the American Economic Association and the Econometric Society now use Refine’s AI-assisted technical verification as part of their publication processes.
Here is the thread. And more comments here.
The Binmen of Birmingham
I was on the British CapX Podcast talking about the Equality Act, riffing off my two posts Equality Act 2010 and The Apples and Oranges Tribunal. One thing I discussed in the podcast which I haven’t blogged on is the amazing Birmingham dustbin dispute.
In 2010 an employment tribunal ruled that Birmingham City Council had discriminated against thousands of female workers — cooks, cleaners, care assistants, caretakers — who were denied bonuses paid to the mostly male binmen, gardeners, and gravediggers. Why were the binmen given bonuses? Well, refuse collection is filthy, heavy, outdoor work and not many people want to be gravediggers. Thus, these jobs command a premium for exactly the reason Adam Smith gave in 1776 — compensating differentials. Or was it sexism? Well, note first that there is nothing stopping women from becoming “binpersons” and indeed there are female binpersons and they earn the same bonuses as their male counterparts (just as with the Next case). Moreover, we can test the sexism versus compensating differentials theory. Let’s see what happened.
Here’s the problem, which contributed to Birmingham going bankrupt in 2023. The council employs roughly 400 binmen and something like 6,000 women in comparable graded roles. Every extra pound paid to a binman therefore implied about fifteen pounds owed to the cooks and cleaners. The council simply didn’t have the money to pay everyone binman wages so they cut the binmen’s wages. But the market wage for collecting rubbish is what it is, so when Birmingham finally deleted the premium in January 2025, the binmen went on strike — and they are still on strike, nearly eighteen months later. The rubbish piled up, 17,000 tonnes of it, and the city declared a major incident.
Here’s the most amazing part. The council hired an outside contractor to take over its rubbish collection and it now pays roughly triple its pre-strike outsourcing bill–more than it was paying its own employees. So much for sexism. Apparently the premium wasn’t a favor to men; it was the price of the job. If you want your rubbish picked up and your graves dug, you must pay the market wage. This was pure regulatory arbitrage, of course. Because the new binmen were contractors they legally had a different employer than the Council’s female caregivers and the Act’s comparator rules stop at the employer’s nexus.
The government mandarins, of course, want to close the “loophole” adding yet another bureaucratic requirement to push the equal pay madness up the supply chain. The rubbish piles up.
Will U.S. cities face a knock-on fiscal crisis from the feds?
Federal money flows to cities in three flavors: direct transfers, indirect transfers, and what we call fiscal dark matter. Direct transfers are exactly what they sound like — money sent directly from the federal government to various localities. These include funds disbursed through programs like the Community Development Block Grant (CDBG), which supports things like public infrastructure and neighborhood services.3 In 2022, direct transfers like the CDBG totaled $146.3 billion.4 That’s significant, but actually the smallest of the three categories.
Less visible are the indirect transfers. These monies are initially awarded to state governments, which then allocate funds to municipal-level programs and services in accordance with state prerogatives. The cleanest example is probably K-12 education, which receives federal Title I dollars to pay for teachers and programs, but federal highway dollars work essentially the same way. All told, in 2022, the federal government handed down $1.1 trillion to state governments. That amounted to 36% of overall state revenue for that year and, depending on the individual state, ranged from roughly 22% to 50% of state revenue. How much of that ultimately flowed down to cities is hard to say, which is itself a problem: it’s difficult to even establish how exposed local governments are to a pullback in federal support of state budgets.
The third category – our fiscal dark matter – is all the federal money spent into local communities that never shows up in a local budget. This includes housing subsidies like the Low-Income Housing Tax Credit (LIHTC) and Section 8. It also includes food support programs like SNAP and even some direct funding for local food banks.
Rightfully or not, when the flow of federal money in this category starts to dry up, the resulting problems will fall squarely on the mayor’s desk. After all, the median voter is never going to see increasing numbers of homeless encampments and think to blame the head of HUD.
Here is the full piece by Jeff Fong.
Who Pays for Unions?
If unions raise worker wages, who pays? We provide a comprehensive assessment of firm responses to increased unionization, using changes in the tax deductibility of union dues in Norway as a quasi-exogenous source of variation in firm-level union density. In the average private sector firm, higher union density raises labor costs and leads firms to contract employment and production, lowering profits without increasing the labor share. The incidence is shared: consumers bear part of the cost through higher prices, shareholders through lower profits, and the remainder is offset by productivity improvements. The total wage bill falls, with losses concentrated among less-attached “outsider” workers. Firm responses vary systematically by the degree of market competition. In manufacturing, where firms operate in less competitive product and labor markets, the response is reversed: the average firm expands employment and production, reduces labor markdowns, and does not experience profit declines. Instead, higher labor costs are largely passed on to consumers through higher prices, with the remainder offset by productivity gains. Workers benefit as both wages and employment rise. These patterns suggest that unions can offset employer monopsony power and that firm responses–and therefore who ultimately bears the cost-depend importantly on market structure. Overall, unionization in this setting primarily redistributes from consumers rather than shareholders and has effects that differ sharply across firms, including a reallocation toward larger and more productive firms. We rationalize these patterns using a partial-equilibrium model of union bargaining with product- and labor-market power.
That is forthcoming in the QJE by Samuel Dodini, Anna Stansbury, and Alexander Willén.
Is this why China finds it so hard to inflate producer prices?
This paper investigates why China’s recurrent credit expansions have coincided with persistently weak inflation. We argue that this pattern reflects the country’s production-oriented monetary regime. At the aggregate level, faster monetary-financial expansion temporarily raises PPI inflation but depresses it over longer horizons. At the sectoral level, liability growth among listed industrial firms is followed by weaker producer prices, lower profitability, higher leverage, rising inventories, and reduced capacity utilization. We also find asymmetric supply-chain transmission: downstream liability growth raises upstream PPI inflation, while upstream liability growth does not generate a corresponding downstream price response. These findings indicate that credit expansion in China tends to sustain production and balance sheets rather than stimulate final demand. As a result, monetary policy operates less as a conventional tool for demand management and durable reflation, and more as a mechanism for preserving production capacity and supporting growth.
That is from a new paper by . I have to say I understand the result but not exactly the mechanism. I am reminded of Milton Friedman’s dictum not to focus too much on the first-order effects of an increase in money supply.
The Value of Behavioral Policies
Behavioral interventions have become central to modern public policy, but their empirical promise remains contested because estimated treatment effects often appear small. We argue that a policy response is economically meaningful only relative to the response generated by alternative policies. We assemble more than 1,200 estimates from over 600 studies comparing “nudges” and traditional price interventions in the markets for cigarettes, alcohol, influenza vaccination, electricity, and residential water. Translating nudge effects into equivalent price changes, we find that behavioral interventions often correspond to enormous fiscal interventions, from an 11% tax on electricity to a 100% subsidy on influenza vaccinations. Nudges are also more cost-effective than price instruments in all markets, but cost-effectiveness does not predict the welfare ranking of policies. Using a behavioral extension of the Marginal Value of Public Funds, we show that nudges have high welfare returns at the margin, while price instruments often generate larger total surplus at scale.
That is from a new NBER working paper by
Estimating the Economic Value of Zoning Reform
We estimate the economic value of zoning reform in São Paulo, which altered maximum permitted construction along transportation corridors. Developers increased filings for multifamily construction in blocks affected by the reform, leading to more housing supply and lower housing prices in neighborhoods that allow more densification. Our equilibrium model of housing markets estimates an aggregate 1.6 percent increase in housing stock and a 0.4 percent reduction in prices, resulting in large housing wealth transfers from current to future homeowners. The reform produced welfare gains of 0.65 percent of city GDP, mostly due to developer profits and consumer gains from the newly built environment.
That is from the AEA policy journal, by Santosh Anagol, Fernando Ferreira, and Jonah Rexer.
The economics of H-1B immigration
We study the effects of H-1B immigration on U.S. industries that employ H-1B workers and their trading partners. Using a novel cross-industry design and the 1999–2003 expansion of the H-1B visa cap for identification, we find that H-1B exposure raised incomes for natives and pre-existing immigrants, with gains concentrated in non-STEM occupations. Income gains propagate forward through supply chains to downstream industries but not backward to upstream industries, consistent with a productivity shock rather than a labor supply shock. We find no direct effect on patenting, suggesting that productivity gains arise from better task execution rather than patentable invention.
That is from a new NBER working paper by
On the Acemoglu-Autor et.al. fertility result
Here is criticism from Revana Sharfuddin. Here is criticism from JFV.
Taiwan fact of the day
Immigration and Macroeconomic Outcomes in OECD Countries
OECD countries experienced declining native population growth and rising net immigration over 1990-2024. We compile a new dataset of net immigration rates to OECD countries from all origins and show that most of the increase came from non-OECD countries and was predominantly high-skilled. Push factors, network effects, and policy indices explain little of the large cross-country heterogeneity in immigration dynamics; unexpected shocks and surges were common. Using local projections and several sources of identifying variation, we then estimate the relationship between immigration and growth in GDP per capita, labor productivity, capital investment, and total factor productivity (TFP). Immigration from non-OECD countries was a significant predictor of GDP per worker growth, primarily through higher investment. High-skilled immigration, in particular, was associated with stronger human capital accumulation, faster TFP growth, and greater capital deepening. Native population growth, by contrast, had no or weakly negative effects on GDP per capita and productivity. These results are consistent with a large literature documenting the positive productivity and growth effects of immigration, especially high-skilled immigration.
That is from a new NBER working paper from
*Redefining Global Health in the 21st Century*
While donor-driven programs undoubtedly saved millions of lives, they also created unintended distortions in national health priorities. Many governments in sub-Saharan Africa and parts of Asia actually scaled back domestic health investments, as donor program filled key gaps in HIV/AIDS, maternal and child health, and infectious disease control. In some cases, domestic health budgets shrank in real terms, even as external funding increased. This phenomenon, often referred to as “fiscal substitution,” led to national health systems that were heavily donor-dependent, externally managed, and vulnerable to funding shocks. Notably, this reliance emerged despite countries pledged to allocate at least 15% of their national budgets to health. More than two decades later, only a handful has met this target.
That is from the new and useful book by Michael John Alastair Reid and Eric Paul Goosby. But $150 for a not so thick volume!? If the authors believe in aid, as they should, perhaps they could consider giving this book away for free rather than turning it over to Elsevier…?
The Apples and Oranges Tribunal
Suppose that apples sell for more than oranges and Parliament in it’s wisdom decides that, at last, apples and oranges must be compared. Not by shoppers — shoppers are biased, they merely reveal what they are willing to pay — but by a tribunal, which will determine whether apples and oranges are of truly equal value and thus must sell at the same price.
What would the tribunal need to know?
Start with land. Orange groves sit on Florida real estate with one set of alternative uses; apple orchards occupy Washington hillsides with another. The opportunity cost of an orange includes the housing development, the solar farm, the tourist attraction not built on that grove. How is the tribunal to value what was never built? Perhaps you answer: look at land prices. Brilliant suggestion, I reply. Keep going.
Next, capital. Orchards take years to mature, so today’s fruit embodies investments made under yesterday’s expectations about today, financed at interest rates the tribunal must somehow incorporate. Then storage: apples keep, oranges rot, so an apple and an orange in April are different goods than the “same” fruits in October. Add transportation, refrigeration, frost, pests, crop insurance, the option to divert fruit into juice, cider, marmalade, or pie, substitution with every other item in the produce aisle, and the shifting preferences of millions of consumers, each of whom knows things about his own breakfast that he could not articulate to a tribunal. It all matters.
To determine the “just” price of apples and oranges, the tribunal would need the entire general-equilibrium system.
Market prices are necessary to compare alternative uses of resources, as Mises taught us in 1920. In 1945, Hayek added the knowledge problem: the relevant knowledge is dispersed, local, tacit, and fleeting. Free markets are the only institution that aggregates that knowledge, articulates it in prices and gives people a reason to listen and respond. A price is a signal wrapped up in an incentive. Apples and oranges can be compared but only by the incomparably complex operations of the price system. There is a reason we call it the super-market.
Britain is now running this experiment in the labor market–Is a retail worker equal to a warehouse worker? A canteen worker equal to a coal miner? A dinner lady equal to a gravedigger?
Under the Equality Act’s “equal value” provisions, tribunals compare jobs by scoring their intrinsic properties — effort, skill, responsibility, working conditions — the labor theory of value applied to labor. How is it going? The Tesco litigation began in 2018; the tribunal’s fact-finding hearing ran 36 days, its judgments run to more than 900 pages resting on some 19,000 pages of training manuals, and the independent experts have yet to begin the report that will actually say whether a shelf-stacker’s job equals a warehouse worker’s. Eight years, and the calculation has not started. Apples and oranges, adjudicated but not, as Orwell or Marx or Stafford Beer might have imagined, by a industrial bureaucracy or by an all-knowing artificial intelligence but by lawyers and commissions and tribunals. The worst of all worlds.
And having discovered that the tribunal cannot price two jobs in a decade, the government now proposes to add race and disability comparisons and an enforcement unit to publish official guidance on which reasons for a wage difference are permissible. A bureau of allowable scarcities.
Moreover, let us say that one day the tribunal reaches its conclusion and finds the truly just apple to orange price. At last, nirvana. The next day the public learns that vitamin C really does combat cancer–the demand for orange juice skyrockets. To encourage more orange juice production we need a higher price but wait…nothing about oranges or apples or the labor required to produce them has changed. We need to attract more labor to the orange juice industry but the effort, skill, responsibility and working conditions of orange juice workers has not changed. How can we justly pay them more than their apple juice brethren? Blank out.
The market compares apples and oranges every day. It is the only institution that can. But there is a deeper error here than computation. Suppose the tribunal succeeded. Suppose that after another decade it delivered the true and final score, shelf-stacker versus warehouseman. What would it have found? Not justice. A wage is not a grade on your character or a measure of your worth as a human being. A wage is a price — a report on how scarce your skills are relative to the desires of people you will never meet. Nurses are not morally less worthy than plumbers should they earn less than plumbers or vice-versa, and no one thinks otherwise except the tribunals.
Hayek nailed it in The Mirage of Social Justice: justice is about conduct — how one person treats another. An employer who defrauds his workers, an employee who steals from the till, a product sold under false pretenses — condemn them, take them to court. But the pattern of prices that emerges from millions of voluntary trades is nobody’s conduct. No one chose it, no one designed it, no one can be guilty of it. The constellation of prices is, in Ferguson’s phrase, the result of human action but not of human design. Demanding that prices be just is a category error, like suing the weather. Prices don’t grade our merit; they guide our actions. Ask them to do the first and they can no longer do the second.
Judge Anthony Kennedy said it well in the Ninth Circuit ruling that (mostly) killed comparable worth in the US: “neither law nor logic deems the free market system a suspect enterprise.”
The AEA presidential election
AEA is the American Economics Association, and a new president is needed, here is the candidate and likely winner:
PINELOPI (PENNY) KOUJIANOU GOLDBERG, William Nordhaus Professor of Economics and Global Affairs, Yale University.
Statement of Purpose: I am honored to stand for President of the American Economic Association. Economics has long contributed powerful tools to understand human behavior, markets, institutions, and public policy, but the environment in which we conduct research, teach, and engage with society is evolving rapidly. New technologies, especially artificial intelligence, are reshaping research methods, classroom instruction, and the evaluation and dissemination of scholarship. These changes create exciting opportunities, but they also raise difficult questions about the future of peer review in our journals, transparency, incentives, and research and teaching standards more generally. The profession also faces broader challenges: maintaining rigorous, credible, and independent research, supporting young scholars in an increasingly uncertain academic environment, and ensuring that economics remains open to diverse perspectives, methods, and global talent. If elected, I hope to use my research, teaching, policy, and editorial experience to help address these challenges, while promoting the core values of our discipline.
Here is the link. Hilarious as always that there is only one candidate allowed (which model predicts this as optimal?), but for the first time I have seen a meaningful statement of purpose that I also like. That said, I would like to see her endorse my core proposal, namely turning over all submissions, referee reports, and revisions (anonymized is fine) to the major AI companies for use as training data. After all, such an act would further the mission of the AEA, right?