Sephorah Mangin

@skyview.social unroll

California vows to ‘instantly’ cut funding to universities that cave to Trump ‘compact’ Governor Gavin Newsom urges schools not to sign ‘radical agreement’ to cuts to departments, students and speech

Newsom: "If any California university signs this radical agreement, they’ll lose billions in state funding – including Cal Grants – instantly. California will not bankroll schools that sell out their students, professors, researchers, and surrender academic freedom"

Economic outcomes often depend on the distribution of some maximum value (e.g. the highest valuation, best idea, or lowest cost).

If the average number of options is large, do such outcomes change when some agents have more options than others?

1/ A thread about this paper 🧵

9/ Thank you to everyone who provided useful comments when I presented this paper seventeen times!

Here is a link to the paper:

www.sephorahmangin.info/current_rese...

I would love to hear your thoughts or questions, so please don’t hesitate to reach out!

8/ It is worth highlighting that the paper uses a very surprising and useful equivalence between mixed Poisson distributions and “invariant” search technologies that was recently discovered by Cai, Gautier, and Wolthoff (2025).

7/ I thank the co-editor Chad Jones and three anonymous referees for extremely insightful suggestions that greatly improved the paper and yielded new results, applications, and proofs. I also thank Louis Becker for his valuable contribution to an earlier version of the paper.

6/ For example, suppose the number of firms in a consumer’s choice set is a random variable that is negative binomial.

Suppose consumers draw utility shocks from a uniform distribution.

Greater consumer heterogeneity increases the average markup.

5/ The paper generalizes a nice result about extreme value outcomes in Gabaix, Laibson, Li, Li, Resnick and de Vries (2016) by incorporating heterogeneity across agents.

For example, the paper delivers a generalization of a result on markups in Gabaix et al.

4/ How do these new EVDs arise?

For example, suppose the number of options an agent gets is a random variable that is negative binomial.

Suppose options are drawn from a Pareto distribution.

The EVD takes this general form. 👇

3/ The paper presents a new class of extreme value distributions (EVDs) that generalizes the three standard EVDs (Fréchet, Gumbel, Weibull) by incorporating heterogeneity across agents.

Here is an example of a new family of EVDs. 👇

2/ My forthcoming Econometrica paper answers this general question.

The paper provides a toolkit that I hope is useful for both macroeconomists and microeconomists alike.

Potential applications include growth, productivity, trade, markups, auctions, networks, IO.

Economic outcomes often depend on the distribution of some maximum value (e.g. the highest valuation, best idea, or lowest cost).

If the average number of options is large, do such outcomes change when some agents have more options than others?

1/ A thread about this paper 🧵

Excited to see this! A thread coming soon…

August 1, 2025 AMERICAN ECONOMIC ASSOCIATION Committee on Economic Statistics and Committee on Government Relations Statement from the American Economic Association on the Dismissal of the BLS Commissioner Leaders of the American Economic Association express their grave concern over the dismissal of the Commissioner of the Bureau of Labor Statistics (BLS) earlier today. The independence of the federal statistical agencies is essential to the proper functioning of a modern economy. Accurate, timely, and impartial statistics are the foundation upon which households, businesses, and policymakers make critical decisions. Undermining the independence or credibility of these agencies threatens the integrity of the information that markets, institutions, and the public rely on every day. Measuring the vast and dynamic U.S. economy in real time is inherently challenging. It is standard practice for statistical estimates to be revised as more complete and higher-quality data become available. These revisions reflect the commitment of statistical agencies to accuracy, transparency, and methodological rigor-not failure or bias. The BLS has long had a well-deserved reputation for professional excellence and nonpartisan integrity. Safeguarding this tradition is vital for the continued health of the U.S. economy and public trust in our institutions. We call upon elected officials to respect and preserve the independence of the nation's statistical infrastructure. Lawrence Katz President, American Economic Association Katharine Abraham President-Elect, American Economic Association Karen Dynan Chair, American Economic Association Committee on Economic Statistics Kenneth Troske Chair, American Economic Association Committee on Government Relations

Statement from the largest economics association about the BLS firing

As context: AEA approximately never makes such public statements

This is a big deal

How do firms search for and screen workers? When do the best workers match with the best firms?

Opinion | America’s Brightest Minds Will Walk Away Young researchers are choosing between staying in science and staying in the United States.

America’s Brightest Minds Will Walk Away

"Of 1,200 U.S. scientists who responded to a poll conducted by the journal Nature, 75 percent said they were considering leaving the country."

www.nytimes.com/2025/04/03/o...

The Federal Reserve is not as independent from the executive branch as we’d like to think. The NY Fed just cancelled this Thursday’s @aeacswep.bsky.social reception at #EEA2025 and withdrew from our summer fellowship program. Both support women and underrepresented groups in economics. #EconSky

Call for Papers! 4th DC Search and Matching will be 4/25-26. Submission deadline 3/10. Send us your papers! www.cvent.com/c/abstracts/...

Spatial search This paper considers a random search model where some locations provide sellers with better chances of meeting many buyers than other locations (for e…

In NYC there is a shop selling cashmere sweaters for dogs, in Amsterdam there is a toothbrush shop. If you are a goth looking for a partner you should move to a city. Finally, there is a forthcoming JET paper explaining this www.sciencedirect.com/science/arti...

Zero-sum thinking is a key mindset that shapes how we view the world. A little thread to highlight our work on its roots with @sahilchinoy.bsky.social,
@nathannunn.bsky.social, Sandra Sequeira.🧵1/23 scholar.harvard.edu/files/stantc...

Congratulations!

When is competition price‐increasing? The impact of expected competition on prices We examine the effect of expected competition on markups in a random utility model where the number of competing firms may differ across consumers. Firms observe consumers' utility shocks and set pri...

When is competition price-increasing?

My latest research has just been published online in RAND:

doi.org/10.1111/1756...

Some of the most important lottery anomalies from the behavioral risk literature (e.g., probability weighting and loss aversion) actually have nothing to do with risk.

They also arise in perfectly deterministic settings.

Lead article in the latest AER issue:
www.aeaweb.org/articles?id=...

I am thankful for the Fundamental Theorem of Calculus, the Implicit Function Theorem, and the Chain Rule.

If only there was a starter pack called "Everyone I follow on Twitter who is on Bluesky"

Intimate Partner Violence (IPV) against women is a major public health and inequality concern. It's not clear what causes it or how to reduce it. Gaby Deschamps' JMP considers that IPV is positively correlated with motherhood, and asks if we can understand why. www.gabrieladeschamps.com/research

A letter on Philosophy & Public Affairs letterhead that reads: November 12, 1973 Professor Robert Nozick Department of Philosophy Emerson Hall Harvard University Cambridge, Massachusetts 02138 Dear Professor Nozick, I have been meaning to send you a note ever since you did not telephone the second time last week just to say that I decided after all to drop the offending post-apostrophes from the possessive of Rawls. This is, as I told you, according to the Chicago Manual of Style an honor due only to Moses and Jesus, but with us aesthetic considerations won out. The decision puts us somewhat in a class by ourselves -- I note that in Brian Barry's new book he and Oxford Press write Rawls's -- but I don't mind being different. I trust that you will not. sincerely， Margot Cutter

November 12, 1973 --- The day Philosophy & Public Affairs started treating Rawls like Jesus.

Making it easier for people to get high has some negative public health impacts.

www.nber.org/system/files...

Drop politics. Drop regressions. Drop reading papers.

Listen to this.
It's OK to get emotional.
open.spotify.com/album/6bqe0N...