Jason Fletcher

In the classic Chains of Affection paper in AJS, Bearman et al found that four-cycles -- two couples switch partners -- were non-existent in a network of high schoolers romantic ties. They also found a giant component of exes exes.

I take their ideas to the full network of Norwegian partnerships.

A Hidden Productivity Gain from AI: Testing, Reporting, and Abandoning Low-Return Ideas Lots of concern abounds in academia (and other places) that Claude will replace us.

Substack: A Hidden Productivity Gain from AI: Testing, Reporting, and Abandoning Low-Return Ideas

Running up that hill...how will AI shape pre and post tenure research productivity? scott cunningham has a poetic ode to being a researcher who loves research and some worries about what AI will do/is doing to people like that (him, me, you).

Substack: Running up that hill...how will AI shape pre and post tenure research productivity?

Saving lives: lifting many boats or patching holes Two papers in the newest issue of the Journal of Health Economics highlight an open question in research on US mortality—how should we consider tradeoffs between investing in early life and investing ...

Substack: Saving lives: lifting many boats or patching holes

Hidden Curriculum: picking journals New paper: “Submissions Related to Editors’ Research Are More Likely To Succeed: Evidence From Economics Journals” shows evidence that (1) editors are less likely to desk reject manuscripts related to...

Substack: Hidden Curriculum: picking journals

Fingers crossed--I think universities are likely to make rules that exclude this option

The Return of the Office Supercomputer For several decades, many universities solved the computing problem.

Substack: The Return of the Office Supercomputer

AI and Bottlenecks in Academic Publishing Desk rejections ramp up; Creativity still wins out

Substack: AI and Bottlenecks in Academic Publishing

Wide variation in predictions! what is your view?

Acting on the advice of others: focus on illuminating tradeoffs and not on (others') outcomes Why advice based on success stories shields you from the real decisions that matter.

Substack: Mentoring advice

Two regrettable rules for junior scholars: AI supercharges my long standing advice (post 4 of 4) AI doesn’t change the pre‑tenure advice.

Substack: Two regrettable rules for junior scholars: AI supercharges my long standing advice (post 4 of 4)

open.substack.com/pub/jasonmfl...

Two regrettable rules for junior scholars: second rule: be an adequate teacher (post 3 of 4) Don’t try to be an excellent teacher in years 1–3.

Substack: Two regrettable rules for junior scholars: second rule: be an adequate teacher (post 3 of 4)

Peter Attia in my feed twice this week We’ve seen that Peter Attia was involved with Epstein and stepped down from some positions: https://www.nytimes.com/2026/02/23/well/peter-attia-cbs-epstein.html

substack: Peter Attia in the news again
tinyurl.com/4ys7avcs

Two regrettable rules for junior scholars: rule one, (not) working with graduate students (post 2 of 4) Why working with graduate students is often negative expected value (for pre‑tenure output)

Substack: Why working with graduate students is often negative expected value (for pre‑tenure output)

AI-integrated research; a novel tradeoff and partial solution (part 1 of n) Moving all your project ideas forward by "one step" but also adding a new bottleneck

My Substack: AI-integrated research; a novel tradeoff and partial solution (part 1 of n) open.substack.com/pub/jasonmfl...

Two regrettable rules for junior scholars (and why I’m writing them down) (post 1 of 4) File Under: Mentoring

From my Substack: Two regrettable rules for junior scholars (and why I’m writing them down) (post 1 of 4)

tinyurl.com/379ucn8w

NIH's Bhattacharya will also run the CDC while Trump administration looks for a permanent director The director of the National Institutes of Health is also taking over as acting head of the Centers for Disease Control and Prevention, according to an administration official.

National Institutes of Health Director Jay Bhattacharya will also temporarily become acting director of the Centers for Disease Control and Prevention, an administration official said Wednesday.
https://to.pbs.org/4tJjH19

The Mentorless Apprentice Power, mentorship, and AI in empirical social science

The Mentorless Apprentice
open.substack.com/pub/jasonmfl...

📢🧬 Call for Papers — 5th ESSGN Conference
📍 Bologna, May 21–22, 2026

I’ll be co-organising the 5th ESSGN conference in Bologna together with Nicola Barban, Stephanie von Hinke, Paul Hufe, and Niels Rietveld @essgn.bsky.social

📄 Submit here: forms.gle/fmVDUrQqQYju...
🗓 Deadline: 1 March 2026

Shamelessly tagging a few people for reposts and share #ESSGN5conf

@nicolabarban.bsky.social @paulhufe.net @aysuo.bsky.social @dr-appie.bsky.social @michelnivard.bsky.social @rafaelahlskog.bsky.social @danbelsky.bsky.social @kph3k.bsky.social @jasonmfletcher.bsky.social @rosacheesman.bsky.social

I probably agreed, but remind me your view on what was most wrong?

Social contagion theory: examining dynamic social networks and human behavior Here, we review the research we have conducted on social contagion. We describe the methods we have employed (and the assumptions they have entailed) to examine several datasets with complementary st...

Their counter-claim was that the effects on height, etc, could be plausible and that we misinterpreted our results--instead, we found three new instances of contagion

doi.org/10.1002/sim....

Thoughts from a newbie using Claude Code for the first time.

I don’t always use GitHub for my projects, but with Claude Code it feels like a must. Having a tool read and write files without version control is just too scary.

Columbia Poised to Tap Wisconsin’s Mnookin as Its Next President Columbia University is preparing to name Jennifer Mnookin, chancellor of University of Wisconsin-Madison, as its next president, according to people with knowledge of the matter, completing a search t...

www.bloomberg.com/news/article...

Econ and CS collaboration conference on AI (etc.) Just a few days left to submit a paper. mailing.econometricsociety.org/t/r-e-tkdhid...

@johnmullahy.bsky.social

Confounding fuels misinterpretation in human genetics Abstract. The scientific literature has seen a resurgence of interest in genetic influences on human behaviour and socioeconomic outcomes. Such studies fac

Useful analysis by @arbelharpak.bsky.social‬ and co-authors
"Confounding fuels misinterpretation in human genetics"
doi.org/10.1098/rspb...

Your Genes Are Simply Not Enough to Explain How Smart You Are Seven years ago, I took a bet with Charles Murray about whether we’d basically understand the genetics of intelligence by now.

In 2018, Eric Turkheimer took a bet with Charles Murray, who said that by 2025, the genetics of intelligence would be basically understood. Turkheimer knew otherwise. “I am here to declare that I was more right,” Turkheimer writes.

Trend breaks in life expectancy in the United States over 120 years and potential sources of future gains Research indicates a significant slowdown in life expectancy growth in the United States (US) post 2010, marking a departure from the consistent progress in longevity throughout the twentieth centu...

The first paper from my postdoc is now live. I learnt a lot from my mentor/coauthor @jasonmfletcher.bsky.social in this and our other projects.

Full article: Trend breaks in life expectancy in the United States over 120 years and potential sources of future gains www.tandfonline.com/doi/full/10....

Yo #econsky, we're hiring a new Chair for the School of Economics at Georgia Tech (we always do external searches). Come steer the ship!

We have a great, vibrant group of applied micro faculty and students (enviro, health, dev, trade) + metrics + theory.

www.aeaweb.org/joe/listing....

My quote of the day

My dad used to say: “Don't tell me what you value. Show me your budget, and I'll tell you what you value."

Joseph R. Biden, Jr.