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Jon Hartley Profile picture
Jon Hartley
@Jon_Hartley_
Macro/Labor/Finance; @HooverInst Policy Fellow @Stanford Econ PhD(c) @UT_Civitas @FREOPP @Mercatus @MLInstitute @CapAndFreedom @EconClubofMiami
Aug 27 • 48 tweets • 14 min read
In honor of the upcoming Celebration in Honor of Thomas Sowell happening this October at the Hoover Institution (@HooverInst), here is a chronological list of all 47 of Sowell's books with an accompanying summary for each along with an image of the book's cover. A thread🧵 Image
Image 1: Say’s Law: An Historical Analysis (1972)
Sowell’s first major work — a scholarly history of Say’s Law (the idea that "supply creates its own demand") and its critics, tracing debates from the classical economists to Keynes.Image
Jul 9 • 4 tweets • 2 min read
🚨The big upward trend in Generative AI/LLM tool use in 2025 continues but may be slowing. An update to our paper "The Labor Market Effects of Generative AI" tracking LLM adoption w surveys (finding LLM use at work went from 30.1% [December 2024] to 45.6% [June 2025]). Thread🧵 Image Google search data from Google Trends suggests that searches for "ChatGPT" both in the US and Worldwide have roughly doubled in 2025. Image
Jun 22 • 10 tweets • 6 min read
A thread 🧵 list of the most successful undergraduate theses/student papers of all time:
1. Fred Smith (Yale University, 1966). Proposal for an integrated air–ground delivery system. Became FedEx, a global logistics company. 2. Wendy Kopp (Princeton University, 1989) "An Argument and Plan for the Creation of the Teachers Corps". Founded Teach For America, placing thousands in public schools. Image
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Jun 10 • 10 tweets • 4 min read
"The Elastic Markets Hypothesis" new paper w Felix Gerding. Using country index additions/subtractions, we find multipliers (of flows on stock market prices) are not as high or permanent as recent lit. Stock market demand may be inelastic in short-run but is elastic in long-run🧵 Image Full "Elastic Markets Hypothesis" Paper is here: papers.ssrn.com/sol3/papers.cf…
The literature demand curves for stocks really begins with Shleifer's famous "Do Demand Curves for Stocks Slope Down?" which uses index reconstitution (note for micro elasticities)
jstor.org/stable/2328486… Image
May 20 • 10 tweets • 4 min read
🚨There has been a massive surge in Generative AI/LLM tool use in 2025. An update to our paper "The Labor Market Effects of Generative AI" tracking LLM adoption using surveys (finding LLM use at work has increased ~30% to ~40% in 2025). Thread🧵along w other evidence of the surge Image Our U.S. survey evidence has found significant increases in Gemini and ChatGPT use during this period of time. ChatGPT and Gemini remain the most widely used tools. Image
Apr 15 • 9 tweets • 3 min read
A new @voxeu column of mine w/ Alessandro Rebucci (@arebucci1): "Tariffs, the dollar, and equities: High-frequency evidence from the Liberation Day announcement". Some key figures and a thread🧵 on how global financial markets have responded since 4/2/2025 cepr.org/voxeu/columns/… The post-Liberation Day depreciation of the USD is surprising as it is contrary to predictions of standard international macroeconomic models and the evidence (including from the first Trump tariffs) that domestic currency exchange rates shift to offset a tariff by appreciating. Image
Apr 9 • 8 tweets • 4 min read
New paper on ***Survey R-star***, which we need to all start using. Model-based r-star (eg Laubach-Williams) have massive standard errors. Instead we should increasingly use median survey estimates from recently developed central bank surveys🧵
Paper: papers.ssrn.com/sol3/papers.cf…Image Model-based estimates of r-star have been divergent since the pandemic. Laubach-Williams has been falling while Lubik-Matthes moving upward. How do we know what we can trust when both have massive standard errors? Turning to surveys and median-survey estimates can meaningfully help.Image
Feb 14 • 20 tweets • 6 min read
New Gen AI paper🚨: "The Labor Market Effects of Generative Artificial Intelligence" with Filip Jolevski (@FilipJole), Vitor Melo (@MeloVitor_), and Brendan Moore (@BrendanDMoore). papers.ssrn.com/sol3/papers.cf…Image Our headline takeaway: 30.1% of survey respondents above 18 have used Generative AI at work since Generative AI tools became public, consistent with other survey estimates such as those of Pew and Bick, Blandin, and Deming (2024) (which instead uses Qualtrics; we use IncQuery). Image
Dec 7, 2024 • 12 tweets • 5 min read
A thread🧵on my new paper: "Does Government Debt Management Matter? High Frequency Identification From U.S. Treasury Quarterly Refunding Announcements" with Lorenzo Rigon (1/N) papers.ssrn.com/sol3/papers.cf…Image Government debt management is a classic question in macroeconomics and finance: if the government has to issue X in debt, how much should it issue at different tenors/maturities? (2/N)
Dec 7, 2024 • 13 tweets • 5 min read
Thread🧵of those who attended Notre Dame's reopening: heads of state, clergy, firefighters who saved it, workers who rebuilt it, laity, the disabled. Rebuilding⛪️in 5 years shows we can still build great things, honor our sacred traditions & continue to live them. A historic day Image French Presidents past and present: Macron, Sarkozy and HollandeImage
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Dec 2, 2024 • 10 tweets • 5 min read
The Brightline, a newly *privately* constructed, owned, and operated Florida railway from Miami to Orlando, is the most successful infrastructure story today in America. A thread on how it got done, how nice it is, and how it plans to replicate its success across America 🇺🇸 🧵 Image
Image In 2007, Wes Edens and Fortress Investment Group, LLC used private equity funds to purchase Florida East Coast Industries (FECI), Florida's oldest & largest rail/infrastructure company for $3.5 billion. It was originally founded by South Florida pioneer Henry M. Flagler. Image
Jul 24, 2024 • 17 tweets • 6 min read
1: Thread on nuclear policy, regulations and some of the potential scarring effects (& non-effects) of nuclear disasters. Summary: scarring effects of nuclear disasters which lasted decades are starting to wane as the world looks to nuclear energy as a source of clean energy Image 2: Some history: Ralph Nader's Critical Mass Energy Project formed in 1974 became the largest U.S. anti-nuclear group created false claims, convincing many Americans that nuclear energy from nuclear power plants had extreme far reaching negative health and environmental effects. Image
May 29, 2024 • 13 tweets • 3 min read
A short summary of today's @JMilei speech at @Stanford @HooverInst; very technical economics heavy speech covering econ history, growth, general vs. partial equilibrium; dangers of models. Overall, critical of how economics has used market failure to justify state intervention. Image 2: Began with a discussion of intervention of the state and socialism. Much discussion of Hayek, Friedman and general equilibrium. Principle of noninterference good. Argues state intervention during COVID-19 pandemic caused 100k additional deaths in Argentina
Mar 22, 2024 • 8 tweets • 3 min read
My paper with @Felix_Gerding "De-Dollarization? Not So Fast" is now published in Economics Letters. We find that U.S. dollar dominance has been totally unchanged across many metrics since COVID & the 2022 Russian invasion of Ukraine/related sanctions🧵 sciencedirect.com/science/articl… The US dollar share of central bank FX reserves has remained largely unchanged since early 2022. Image
Mar 16, 2024 • 12 tweets • 4 min read
Yesterday marked 10 years since the release of Piketty's "Capital In The 21st Century". Hard to think of an economics book in the past 10 years which, for better or worse, has had as much influence on discussion about economics, policy and politics. A Thread🧵Image
Image Measuring Top 1% income shares is difficult. Auten-Splitner using unreported earnings find after-tax top 1% income shares have been essentially flat since the 1960s unlike the Piketty-Saez-Zucman who find shows substantial increases. Capital21 didn't show after-tax Top 1% shares Image
Mar 13, 2024 • 17 tweets • 24 min read
In latest @CapAndFreedom ep, Steve Levitt talks his career & retiring as @UChicago prof while still leading RISC & Freakonomics. We talk applied economics, Chicago econ dept (price theory failure, macro success, personalities), Freakonomics origin & more podcasts.apple.com/us/podcast/ste… Podcast episode full transcript: capitalismandfreedom.substack.com/p/episode-28-s…
Jan 28, 2024 • 4 tweets • 2 min read
NFL 4th down attempts have skyrocketed since the 2018 NFL season. Amazing how such a simple insight that increases win probability, encapsulated in David Romer's 2006 Journal of Political Economy (@JPolEcon) article, took over 10 years to get coaches/GMs/owners on board. (1/4) Image "Do Firms Maximize? Evidence from Professional Football" (2006 JPE) by David Romer (2/4) journals.uchicago.edu/doi/full/10.10…
Jun 13, 2023 • 7 tweets • 3 min read
1: Am launching a new website "De-Dollarization Facts" (related paper "De-Dollarization? Not So Fast" ) tracking the status of the U.S. dollar and provide facts in the "de-dollarization" debate which often ignores just how dominant the US dollar is. THREAD de-dollarization.org 2: There are an almost endless number of commentators saying it's the end of the dollar (many from crypto/CBDC communities and intl political interests opposed to the US); most recently with JP Morgan, Goldman Sachs, State Street analysts jumping on this train. Not so fast. (2/N)
Mar 31, 2023 • 4 tweets • 2 min read
Today the IMF released 4Q2023 COFER data: the US dollar share of world reserves DECREASED from 59.8% in 3Q2022 to 58.4% in 4Q2022, the lowest level since Russia invaded Ukraine in 2022. Could this be the start of declining dollar dominance amid geopolitical realignment? THREAD🧵 Much short-run variation reflect changes in the USD FX spot price and FX reserve managers being slow to rebalance. USD massively sold off in 4Q2022, nonetheless, US dollar indices finished the end of 2022 MUCH HIGHER than at start of Russia invasion; dollar share now LOWER.
Sep 30, 2022 • 7 tweets • 6 min read
Today the IMF released the 2Q2022 COFER data, the first full quarter of data since the beginning of the Russian invasion of Ukraine. US dollar share of world reserves actually INCREASED to 59.53% in 2Q2022 up from 58.85% in 2022Q1 and 58.81% in 2022Q4! Dollar Dominance? THREAD🧵 Not the result I was expecting. To be sure there are a lot of concurrent events happening including the worst global inflationary spiral since the 1970s; however, dollar share of reserves usually decreases during inflationary spirals like in the 1970s/1980s per Eichengreen (2014)
Aug 8, 2022 • 12 tweets • 3 min read
A poor twist in tax policy with the "Inflation Reduction Act": tossing out closing carried interest loophole (a logical move to treat general partner income like ordinary income) yet creates a 1% buyback tax (when buybacks are already taxed through cap gains taxes): An EXPLAINER: 2: Backstory: in 2003, the div tax rate was cut to 15% (same rate as long term cap gains) to remove the tax advantage then afforded to buybacks. Firm dividend issuance was previously declining rapidly; see "Disappearing Dividends" of Fama and French (2001) sciencedirect.com/science/articl…