Autism Hasn’t Increased
Autism diagnoses have increased but only because of progressively weaker standards for what counts as autism.
The autistic community is a large, growing, and heterogeneous population, and there is a need for improved methods to describe their diverse needs. Measures of adaptive functioning collected through public health surveillance may provide valuable information on functioning and support needs at a population level. We aimed to use adaptive behavior and cognitive scores abstracted from health and educational records to describe trends over time in the population prevalence of autism by adaptive level and co-occurrence of intellectual disability (ID). Using data from the Autism and Developmental Disabilities Monitoring Network, years 2000 to 2016, we estimated the prevalence of autism per 1000 8-year-old children by four levels of adaptive challenges (moderate to profound, mild, borderline, or none) and by co-occurrence of ID. The prevalence of autism with mild, borderline, or no significant adaptive challenges increased between 2000 and 2016, from 5.1 per 1000 (95% confidence interval [CI]: 4.6–5.5) to 17.6 (95% CI: 17.1–18.1) while the prevalence of autism with moderate to profound challenges decreased slightly, from 1.5 (95% CI: 1.2–1.7) to 1.2 (95% CI: 1.1–1.4). The prevalence increase was greater for autism without co-occurring ID than for autism with co-occurring ID. The increase in autism prevalence between 2000 and 2016 was confined to autism with milder phenotypes. This trend could indicate improved identification of milder forms of autism over time. It is possible that increased access to therapies that improve intellectual and adaptive functioning of children diagnosed with autism also contributed to the trends.
The data is from the US CDC.
Hat tip: Yglesias who draws the correct conclusion:
Study confirms that neither Tylenol nor vaccines is responsible for the rise in autism BECAUSE THERE IS NO RISE IN AUTISM TO EXPLAIN just a change in diagnostic standards.
Earlier Cremieux showed exactly the same thing based on data from Sweden and earlier CDC data.
Happy New Year. This is indeed good news, although oddly it will make some people angry.
Top Posts of 2025
Here are the top MR posts of 2025 as measured by page views. Number one post goes to Tyler:
An excellent post that pairs well with another Tyler post, also in the top ten, A median voter theory of right-wing populism which has the punchline:
The right-wing populists are gaining ground in so many countries because the cultural liberals in various parliaments and congresses are extremely reluctant to meet the preferences of their median voters.
Number two was also a Tyler post. Why I think AI take-off is relatively slow, an excellent accounting of AI economic and institutional bottlenecks. This pairs well with another top-ten post in which Tyler announces that AGI is already here. Both posts are correct. An interesting conundrum.
Third and fourth are two of my posts:
3. UCSD Faculty Sound Alarm on Declining Student Skills
4. One-Third of US Families Earn Over $150,000
Next is Tyler’s rundown of non-fiction books. Well worth re-reading.
5. Best non-fiction books of 2025 with one late addition.
Next I was pleased to see my post in which I explain some standard economics but in a deeper, more fundamental way than is usually done: One of my favorite posts of the year:
Why Do Domestic Prices Rise With Tariffs?
Zephyr Teachout’s op-ed wasn’t fun to read but I admit I did have some fun writing a response
Here’s another issue which makes me mad. The destruction of boarding houses, a perfectly reasonable housing form that reduces homelessness. Or to put it more simply, why is sharing a house illegal? Outrageous.
The War on Roommates: Why Is Sharing a House Illegal?
I am all for American greatness but the approach of the Trump administration is often backwards. I pointed out the big differences between the Sputnik moment and what I called the DeepSeek Moment in two posts.
The Sputnik vs. DeepSeek Moment: Why the Difference? and The Sputnik vs. Deep Seek Moment: The Answers.
I was pleased that David Brooks picked up on my framing in the NYTimes.
Finally my post The Library Burned Slowly sparked a brief spat with Chris Rufo. Rufo’s ability to turn the tools of the left on them is impressive but I haven’t changed my mind that “Bludgeoning your enemies is fun while it lasts but you can’t bludgeon your way to a civilization.”
What were your favorite posts of the year, either at MR or elsewhere?
The Hainan Free Trade Port
Earlier I wrote about China’s Libertarian City, Boao Hope City (officially the Boao Lecheng International Medical Tourism Pilot Zone), China’s first special economic zone for advanced healthcare. Boao Hope City is following the peer approval model I have long argued for:
Daxue: Medical institutions within the zone can import and use pharmaceuticals and medical devices already available in other countries as clinically urgent items before obtaining approval in China. This allows domestic patients to access innovative treatments without the need to travel abroad…. The medical products to be used in the pilot zone must possess a CE mark, an FDA license, or PMDA approval, which respectively indicate that they have been approved in the European Union, the US, and Japan for their safe and effective use.
Boao Hope City is part of the larger Hainan Free Trade Zone. Hainan is a large island off China’s Southern Coast, often called the Hawaii of China. The entire island is being turned into the world’s largest free trade zone. As of Dec. 18, 2025, Hainan now boasts:
- Expanded “Zero-Tariff” Coverage…“zero-tariff” eligible goods expand from about 1,900 to approximately 6,600 tariff lines, increasing coverage from 21% to 74% of total import/export items, encompassing most production equipment and raw materials. This exemption applies to import tariffs, import VAT, and consumption tax, potentially saving enterprises about 20% in tax costs on imported equipment.
- Optimized “Tariff Exemption for Value-added Processing” Policy: One of the most transformative measures, this policy sees significantly relaxed restrictions (e.g., on core business income ratios) and now allows cumulative value-added calculation across upstream and downstream enterprises. This makes it easier for businesses to meet the “over 30% value-added” threshold for tariff exemption when selling finished products into the mainland market. Companies can ship primary products or components to Hainan for substantial processing; if the value-added meets the standard, the final products can enter the mainland market tariff-free.
- “Dual 15%” Tax Incentives as a Long-term Advantage: Encouraged industries registered and substantively operating in the Hainan FTP enjoy a reduced 15% corporate income tax rate. Eligible high-end and in-demand talents benefit from an individual income tax exemption for the portion exceeding 15%, providing long-term, stable fiscal predictability.
- Enhanced Trade and Investment Liberalization/Facilitation: Measures include implementing a negative list for cross-border trade in services, relaxing foreign investment access, adopting a “commitment-based registration system” for business setup, and streamlining procedures. A visa-free policy for nationals of 59 countries is in effect, with further eased entry-exit restrictions for business personnel.
Merry Christmas
Three that Made a Revolution
Another excellent post from Samir Varma, this time on the 1991 reforms in India that launched India’s second freedom movement:
Three men you’ve probably never heard of—P.V. Narasimha Rao, Manmohan Singh, Montek Singh Ahluwalia—may be the three most important people of the late 20th century.
Bold claim. Audacious, even. Let me defend it.
Here are the numbers. In 1991, over 45% of Indians lived below the poverty line—roughly 400 million people. By 2024, extreme poverty in India had fallen to under 3%.
That’s 400 to 500 million people lifted out of poverty.
The largest democratic poverty alleviation in human history.
….So there they stood.
The precipice was visible. A Hindu politician from a dusty village in Telangana who spoke 17 languages and wrote novels nobody wanted to read. A Sikh economist from a village that no longer existed, who took cold showers at Cambridge and kept dried fruits in his pockets. Another Sikh economist who’d been the youngest division chief in World Bank history and wrote a memo that would change a country.
Three men. All products of a civilization that absorbs contradictions—that somehow fits Hindus and Sikhs and Muslims and Christians and Jains and Buddhists and Parsis into one impossibly diverse democracy. A civilization where, as I’ve written before, any statement you make is true, AS IS its opposite.
India was bankrupt. The gold was gone. The Soviet model they’d followed for forty years was collapsing in real time. Every assumption that had guided Indian economic policy since independence was being revealed as catastrophically wrong.
The intelligentsia still believed in socialism. The party cadres still worshipped Nehru’s memory. The opposition would scream about selling out to foreign powers. The bureaucracy would resist losing its control. The protected industries would fight to keep their monopolies.
But the three men had something their opponents didn’t: a plan. The M Document—the years of thinking—the technocratic expertise accumulated across decades. They had political cover—Rao’s tactical genius, his willingness to let Singh take the heat while he worked the back channels. They had credibility—Singh’s Cambridge pedigree, Ahluwalia’s World Bank experience, Rao’s decades of political survival.
And they had something else: the crisis itself. The one thing that could break through forty years of socialist inertia. The emergency that made the previously impossible suddenly necessary.
Varma tells the story well. For the full history consult the indispensable The 1991 Project, full of documents, oral histories and interviews.
Hat tip: Naveen Nvn.
Bring Back the Privateers!
Senator Mike Lee has a new bill that encourages the President to authorize letters of marque and reprisal against drug cartels:
The President of the United States is authorized and requested to commission, under officially issued letters of marque and reprisal, so many of privately armed and equipped persons and entities as, in the judgment of the President, the service may require, with suitable instructions to the leaders thereof, to employ all means reasonably necessary to seize outside the geographic boundaries of the United States and its territories the person and property of any individual who the President determines is a member of a cartel, a member of a cartel-linked organization, or a conspirator associated with a cartel or a cartel-linked organization, who is responsible for an act of aggression against the United States.
SECURITY BONDS.—No letter of marque and reprisal shall be issued by the President without requiring the posting of a security bond in such amount as the President shall determine is sufficient to ensure that the letter be executed according to the terms and conditions thereof.
My paper on privateers explains how privateers were historically very successful. During the War of 1812, roughly 500 privateers operated alongside a tiny U.S. Navy. The market responded swiftly—privateers like the Comet were commissioned within days of war’s declaration and began capturing prizes within weeks. Sophisticated institutional design combined combined profit incentives with regulatory constraints:
- Security bonds ensured compliance with license terms
- Detailed instructions protected neutral vessels and required civilized conduct
- Prize courts adjudicated captures and distinguished privateers from pirates
- Share-based compensation created good incentives for crews
- Markets emerged where crew could sell shares forward (with limits to maintain work incentives)
Privateers cost the government essentially nothing compared to building and maintaining a navy. Private investors financed vessels , bore the risks, and operated on profit-seeking principles. Moreover, privateers unlike Navy vessels had incentives to capture enemy ships, particularly merchant ships, not just blow them and their occupants out of the water. Of course, capturing the drugs isn’t very useful but it’s quite possible to go after the money on the return journey–privateers as hackers–which is just as good.
Here is my paper on privateering, here is the time I went bounty hunting in Baltimore, here is work on the closely related issue of whistleblowing rewards and here is the excellent historian Mark Knopfler on privateering:
Rent Control Creates Ghost Apartments
Adam Lehodey writing at City Journal:
In New York City, making a profit on real estate has become increasingly difficult. Rent-stabilization laws built on the mantra that “housing is a human right,” a dysfunctional housing court, and myriad other interventions have driven thousands of units off the market, giving rise to the phenomenon of New York’s “ghost apartments.”
The city now has nearly 50,000 empty units, absent from the market either because their operating costs exceed legal rents or because they require considerable renovations.
…Take a building on East 6th Street as an example. A mere five-minute walk from Tompkins Square, the building is a convenient home for students and young professionals.
One-bedroom units in the building average $3,500— except two of them, subject to the city’s rent-stabilization laws, which hold rents below $900 per month.
As a result, both units have been allowed to fall into disrepair, because the cost of restoring them to habitability is greater than what they’d generate in rent.
…Much of the predicament at the East 6th Street building and the apartments on Valentine Avenue can be traced back to one piece of legislation: the 2019 Housing Stability and Tenant Protection Act (HSTPA). Passed by a Democratic majority in the state legislature, HSTPA eliminated landlords’ abilities to raise rents after units were vacated, or when they exceeded $2,775 per month. In doing so, it also eliminated their ability to make improvements profitably and reset the stabilized rent.
Recall from the recent review by Kholodilin that “the published studies are almost unanimous with respect to the impact of rent control on the quality of housing….[namely] that rent control leads to a deterioration in the quality of those dwellings subject to regulations.”
Voices From 2099
Great little video. Winner of the Foresight Institute’s $10,000 prize for Existential Hope. Go Bryan Johnson!
Robot Lab
Google’s Deep Mind Lab is going to build a materials science lab in the UK, manned by robots and humans:
To help turbocharge scientific discovery, we will establish Google DeepMind’s first automated laboratory in the UK in 2026, specifically focused on materials science research. A multidisciplinary team of researchers will oversee research in the lab, which will be built from the ground up to be fully integrated with Gemini. By directing world-class robotics to synthesize and characterize hundreds of materials per day, the team intends to significantly shorten the timeline for identifying transformative new materials.
This is a very big deal. Gemini won’t just read papers. It will design the experiments, run the experiments, learn from the successes and failures and then recursively improve. It’s an attempt to learn the game of material science in the same way AlphaGo learned the game of Go.
Growth Matters
Between 2011 and 2023 India’s GDP per capita grew at a rate of about 4.8% per year so in those 12 years GDP per capita, a good measure of the standard of living, nearly doubled (77%). Shamika Ravi and Sindhuja Penumarty look at what this means on the ground.
The percentage of the budget spent on food has declined–dropping below 50% for the first time ever–and that has enabled significant purchases of consumer durables.
It will perhaps not be surprising that mobile phones have become universal among both the poor and the rich but vehicle ownership is also converging with rural ownership of a vehicle (2 or 4 wheeler) nearly tripling from (19% to 59%).
Another standout is refrigerators which reflects growing income and reliable electricity. In the 12 years across the survey, refrigerator ownership in rural areas more than tripled from 9.4% circa 2011 to 33.2% in 2023. In urban areas refrigerator ownership went from less than half (43.8%) to more than two-thirds (68.1%) of urban households. Overall, only two states Bihar (37.1%) and Odisha (46.3%), had less than 50% of urban households owning a refrigerator in 2023-24.
Economists are often accused of “line go up” thinking but the truth is that line go up matters. The 4.8% annual growth matters because it shows up as a broad, visible upgrade in how people live.
Gans and Doctorow on AI Copyright
Josh Gans had written what I think is the first textbook of AI. Instead of the “big issues” like will AI result in the singularity or the end of the human race, Gans treats AI as a tool for improving predictions. What will better predictions do in legal markets, economic markets, political markets? He generally avoids conclusions and instead explores models of thinking.
I especially enjoyed the chapter on intellectual property rights which maps out a model for thinking about copyright in training and in production, how they interact and the net costs and benefits.
Gans’s chapter usefully pairs with Cory Doctorow’s screed on AI. It’s a great screed despite being mostly wrong. I did like this bit, however:
Creative workers who cheer on lawsuits by the big studios and labels need to remember the first rule of class warfare: things that are good for your boss are rarely what’s good for you.
…When Getty Images sues AI companies, it’s not representing the interests of photographers. Getty hates paying photographers! Getty just wants to get paid for the training run, and they want the resulting AI model to have guardrails, so it will refuse to create images that compete with Getty’s images for anyone except Getty. But Getty will absolutely use its models to bankrupt as many photographers as it possibly can.
…Demanding a new copyright just makes you a useful idiot for your boss, a human shield they can brandish in policy fights, a tissue-thin pretense of “won’t someone think of the hungry artists?…
We need to protect artists from AI predation, not just create a new way for artists to be mad about their impoverishment.
And incredibly enough, there’s a really simple way to do that. After 20+ years of being consistently wrong and terrible for artists’ rights, the US Copyright Office has finally done something gloriously, wonderfully right. All through this AI bubble, the Copyright Office has maintained – correctly – that AI-generated works cannot be copyrighted, because copyright is exclusively for humans. That’s why the “monkey selfie” is in the public domain. Copyright is only awarded to works of human creative expression that are fixed in a tangible medium.
And not only has the Copyright Office taken this position, they’ve defended it vigorously in court, repeatedly winning judgments to uphold this principle.
The fact that every AI created work is in the public domain means that if Getty or Disney or Universal or Hearst newspapers use AI to generate works – then anyone else can take those works, copy them, sell them, or give them away for free. And the only thing those companies hate more than paying creative workers, is having other people take their stuff without permission.
The US Copyright Office’s position means that the only way these companies can get a copyright is to pay humans to do creative work. This is a recipe for centaurhood. If you’re a visual artist or writer who uses prompts to come up with ideas or variations, that’s no problem, because the ultimate work comes from you. And if you’re a video editor who uses deepfakes to change the eyelines of 200 extras in a crowd-scene, then sure, those eyeballs are in the public domain, but the movie stays copyrighted.
AI should not have to pay to read books any more than a human. At the same time, making AI created works non-copyrightable is I think the right strategy at the present moment. Moreover, it’s the most practical suggestion I have heard for channeling AI in a more socially beneficial direction, something Acemoglu has discussed without much specificity.
Mass Incarceration and Mass Crime
In our Marginal Revolution Podcast on Crime in the 1970s, I pointed out that blacks were often strongly in favor of tough on crime laws:
Tabarrok: [P]eople think that mass incarceration is a peculiarly American phenomena, or that it came out of nowhere, or was due solely to racism. Michelle Alexander’s, The New Jim Crow, takes this view.
…[But] back then, the criminal justice system was also called racist, but the racism that people were pointing to was that black criminals were let back on the streets to terrorize black victims, and that black criminals were given sentences which were too light. That was the criticism back then. It was black and white victims together who drove the punishment of criminals. I think this actually tells you about two falsehoods. First, the primary driver of mass imprisonment was not racism. It was violent crime.
Second, this also puts the lie, sometimes you hear from conservatives, to this idea that black leaders don’t care about black-on-black crime. That’s a lie. Many Black leaders have been, and were, and are tough on crime. Now, it’s true, as crime began to fall in the 1990s, many blacks and whites began to have misgivings about mass incarceration. Crime was a huge problem in the 1970s and 1980s, and it hit the United States like a brick. It seemed to come out of nowhere. You can’t blame people for seeking solutions, even if the solutions come with their own problems.
A new paper The Racial Politics of Mass Incarceration by Clegg and Usmani offer more evidence challenging the now conventional Michelle Alexander view:
Public opinion data show that not just the white but also the black public became more punitive after the 1960s. Voting data from the House show that most black politicians voted punitively at the height of concern about crime. In addition, an analysis of federally mandated redistricting suggests that in the early 1990s, black political representation had a punitive impact at the state level. Together, our evidence suggests that crime had a profound effect on black politics. It also casts some doubt on the conventional view of the origins of mass incarceration.
As the authors note, the fact that blacks supported tough-on-crime laws doesn’t mean racism was absent. Racial overtones surely influenced the specific ways fear of crime was translated into policy. But the primary driver of mass incarceration wasn’t racism—it was mass crime.
Crime and the Welfare State
Several recent papers claim that expanding programs like Medicaid reduces crime (e.g. here). I’ve been skeptical, not because of weaknesses in any particular paper, but just because the results feel a bit too aligned with social-desirability bias and we know that the underlying research designs can be fragile. As a result, my priors haven’t moved much. The first paper using a genuine randomized controlled trial now reports no effect of Medicaid expansion on crime.
Those involved with the criminal justice system have disproportionately high rates of mental illness and substance-use disorders, prompting speculation that health insurance, by improving treatment of these conditions, could reduce crime. Using the 2008 Oregon Health Insurance Experiment, which randomly made some low-income adults eligible to apply for Medicaid, we find no statistically significant impact of Medicaid coverage on criminal charges or convictions. These null effects persist for high-risk subgroups, such as those with prior criminal cases and convictions or mental health conditions. In the full sample, our confidence intervals can rule out most quasi-experimental estimates of Medicaid’s crime-reducing impact.
Finkelstein, Miller, and Baicker (WP).
It could still be the case that very targeted interventions–say making sure that released criminals get access to mental health care–could do some good but there’s unlikely to be any general positive effect.
A similar story is found in Finland where a large RCT on a guaranteed basic income found zero effect on crime
This paper provides the first experimental evidence on the impact of providing a guaranteed basic income on criminal perpetration and victimization. We analyze a nationwide randomized controlled trial that provided 2,000 unemployed individuals in Finland with an unconditional monthly payment of 560 Euros for two years (2017-2018), while 173,222 comparable individuals remained under the existing social safety net. Using comprehensive administrative data on police reports and district court trials, we estimate precise zero effects on criminal perpetration and victimization. Point estimates are small and statistically insignificant across all crime categories. Our confidence intervals rule out reductions in perpetration of 5 percent or more for crime reports and 10 percent or more for criminal charges.
My 2011 Review of Contagion
I happened to come across my 2011 review of the Steven Soderberg movie, Contagion and was surprised at how much I was thinking about pandemics prior to COVID. In the review, I was too optimistic about the CDC but got the sequencing gains right. I continue to like the conclusion even if it is a bit too clever by half. Here’s the review (no indent):
Contagion, the Steven Soderberg film about a lethal virus that goes pandemic, succeeds well as a movie and very well as a warning. The movie is particularly good at explaining the science of contagion: how a virus can spread from hand to cup to lip, from Kowloon to Minneapolis to Calcutta, within a matter of days.
One of the few silver linings from the 9/11 and anthrax attacks is that we have invested some $50 billion in preparing for bio-terrorism. The headline project, Project Bioshield, was supposed to produce vaccines and treatments for anthrax, botulinum toxin, Ebola, and plague but that has not gone well. An unintended consequence of greater fear of bio-terrorism, however, has been a significant improvement in our ability to deal with natural attacks. In Contagion a U.S. general asks Dr. Ellis Cheever (Laurence Fishburne) of the CDC whether they could be looking at a weaponized agent. Cheever responds:
Someone doesn’t has to weaponize the bird flu. The birds are doing that.
That is exactly right. Fortunately, under the umbrella of bio-terrorism, we have invested in the public health system by building more bio-safety level 3 and 4 laboratories including the latest BSL3 at George Mason University, we have expanded the CDC and built up epidemic centers at the WHO and elsewhere and we have improved some local public health centers. Most importantly, a network of experts at the department of defense, the CDC, universities and private firms has been created. All of this has increased the speed at which we can respond to a natural or unnatural pandemic.
In 2009, as H1N1 was spreading rapidly, the Pentagon’s Defense Threat Reduction Agency asked Professor Ian Lipkin, the director of the Center for Infection and Immunity at Columbia University’s Mailman School of Public Health, to sequence the virus. Working non-stop and updating other geneticists hourly, Lipkin and his team were able to sequence the virus in 31 hours. (Professor Ian Sussman, played in the movie by Elliott Gould, is based on Lipkin.) As the movie explains, however, sequencing a virus is only the first step to developing a drug or vaccine and the latter steps are more difficult and more filled with paperwork and delay. In the case of H1N1 it took months to even get going on animal studies, in part because of the massive amount of paperwork that is required to work on animals. (Contagion also hints at the problems of bureaucracy which are notably solved in the movie by bravely ignoring the law.)
It’s common to hear today that the dangers of avian flu were exaggerated. I think that is a mistake. Keep in mind that H1N1 infected 15 to 30 percent of the U.S. population (including one of my sons). Fortunately, the death rate for H1N1 was much lower than feared. In contrast, H5N1 has killed more than half the people who have contracted it. Fortunately, the transmission rate for H5N1 was much lower than feared. In other words, we have been lucky not virtuous.
We are not wired to rationally prepare for small probability events, even when such events can be devastating on a world-wide scale. Contagion reminds us, visually and emotionally, that the most dangerous bird may be the black swan.
Welcome to the Crazy CAFE
To let Americans buy smaller cars, Trump had to weaken fuel-efficiency standards. Does that sound crazy? Small cars, of course, have much higher fuel efficiency. Yet this is exactly how the Corporate Average Fuel Economy (CAFE) standards work.
Since 2011, fuel-economy targets scale with a vehicle’s “footprint” (wheelbase × track width). Big vehicles get lenient targets; small vehicles face demanding ones. A microcar that gets 40 MPG might be judged against a target of 50-60 MPG, while a full-size truck doing 20 MPG can satisfy a 22 MPG requirement.. The small car is clearly more efficient, yet it fails the rule that the truck passes.
The policy was meant to be fair to producers of large vehicles, but it rewards bloat. Make a car bigger and compliance gets easier. Add crash standards built around heavier vehicles and it’s obvious why the US market produces crossovers and trucks while smaller and much less expensive city-cars, familiar in Europe and Asia, never show up. At a press conference rolling back CAFE standards, Trump noted he’d seen small “kei” cars on his Asia trip—”very small, really cute”—and directed the Transportation Secretary to clear regulatory barriers so they could be built and sold in America.
Trump’s rollback—cutting the projected 2031 fleet average from roughly 50.4 MPG to 34.5 MPG—relaxes the math enough that microcars could comply again. Only Kafka would appreciate a fuel-economy system that makes small fuel-efficient cars hard to sell and giant trucks easy. Yet the looser rules remove a barrier to greener vehicles while also handing a windfall to big truck makers. A little less Kafka, a little more Tullock.