Johan Ugander
@jugander.bsky.social
Associate Professor, Yale Statistics & Data Science. Social networks, social and behavioral data, causal inference, mountains. https://jugander.github.io/
Pinned
Johan Ugander
@jugander.bsky.social
· Jul 1
📣 Update: I've moved to Yale, joining the Department of Statistics & Data Science as an Associate Professor today (July 1)! The last year's sabbatical here has been great for me and my family, and I am excited for great things ahead! Come visit! Trading the wind of freedom for light and truth!
It's been cold in New Haven for a while. How cold? How long? What about other cities? I used claude code to cook a webtool to explore what I am calling the "cryofront": the minimax curve of how cold it's been, for how long. Feedback welcome! (AI coding is wild y'all.) jugander.github.io/cryofront/
February 9, 2026 at 7:46 PM
It's been cold in New Haven for a while. How cold? How long? What about other cities? I used claude code to cook a webtool to explore what I am calling the "cryofront": the minimax curve of how cold it's been, for how long. Feedback welcome! (AI coding is wild y'all.) jugander.github.io/cryofront/
Knowing some of the authors, the problems have strong "recognize a lion by its claw" energy. 🦁
Ten math problems with proofs known the authors. Proofs are encrypted until Feb 13. For all problems, authors claim both AI-based literature searches and zero-shot attempts at proofs failed. If you want to take a crack, you have until next Friday (2/13)!
First Proof
To assess the ability of current AI systems to correctly answer research-level mathematics questions, we share a set of ten math questions which have arisen naturally in the research process of the au...
arxiv.org
February 8, 2026 at 4:01 PM
Knowing some of the authors, the problems have strong "recognize a lion by its claw" energy. 🦁
Ten math problems with proofs known the authors. Proofs are encrypted until Feb 13. For all problems, authors claim both AI-based literature searches and zero-shot attempts at proofs failed. If you want to take a crack, you have until next Friday (2/13)!
First Proof
To assess the ability of current AI systems to correctly answer research-level mathematics questions, we share a set of ten math questions which have arisen naturally in the research process of the au...
arxiv.org
February 8, 2026 at 3:59 PM
Ten math problems with proofs known the authors. Proofs are encrypted until Feb 13. For all problems, authors claim both AI-based literature searches and zero-shot attempts at proofs failed. If you want to take a crack, you have until next Friday (2/13)!
Most unusual SI/methods write-up I've seen in a while: Digging in Utah scrapbooks for hair samples to document historic lead levels. Remarkable findings, note the log-scaled y-axis.
February 3, 2026 at 3:13 PM
Most unusual SI/methods write-up I've seen in a while: Digging in Utah scrapbooks for hair samples to document historic lead levels. Remarkable findings, note the log-scaled y-axis.
Reposted by Johan Ugander
New on @indicator.media: "@grok is this true" was the single most frequent reply tagging X's AI chatbot in the six months following its launch.
@Grok is this true: How X’s chatbot performs as a fact-checking tool
New research explores whether the chatbot might replace the crowdsourced fact-checking program – and what that might mean for getting to the truth on X
indicator.media
January 28, 2026 at 1:35 PM
New on @indicator.media: "@grok is this true" was the single most frequent reply tagging X's AI chatbot in the six months following its launch.
Reposted by Johan Ugander
On Dec. 30, Santa Clara County, CA held a $13 million runoff for county assessor.
Turnout dropped 53%, and the winning candidate got fewer votes in the runoff than in the general election.
All of this could be avoided w/ #RankedChoiceVoting. @calrcv.bsky.social ⬇️
Turnout dropped 53%, and the winning candidate got fewer votes in the runoff than in the general election.
All of this could be avoided w/ #RankedChoiceVoting. @calrcv.bsky.social ⬇️
Santa Clara County runoff turnout dropped 53%. Ranked choice voting is the solution. - FairVote
Santa Clara County, CA's runoff for county assessor cost taxpayers an estimated $13.1 million, and turnout declined by 53%
fairvote.org
January 26, 2026 at 2:49 PM
On Dec. 30, Santa Clara County, CA held a $13 million runoff for county assessor.
Turnout dropped 53%, and the winning candidate got fewer votes in the runoff than in the general election.
All of this could be avoided w/ #RankedChoiceVoting. @calrcv.bsky.social ⬇️
Turnout dropped 53%, and the winning candidate got fewer votes in the runoff than in the general election.
All of this could be avoided w/ #RankedChoiceVoting. @calrcv.bsky.social ⬇️
The replies to this post surfaced lots of great 3rd party tools (thanks!), but I still think it's interesting that bsky, as a platform, has decided to not prioritize algorithmic triangle closing (or follow recommendations, generally). See this fig from Zignani et al. (2014), when FB introduced PYMK.
January 25, 2026 at 2:39 PM
The replies to this post surfaced lots of great 3rd party tools (thanks!), but I still think it's interesting that bsky, as a platform, has decided to not prioritize algorithmic triangle closing (or follow recommendations, generally). See this fig from Zignani et al. (2014), when FB introduced PYMK.
Huh — bsky has no PYMK ("people you may know") rec sys, it seems? Or? It has a mobile contacts uploader (linked), but it's highly opt-in by design. Lists help some with discovery. But no triadic closure engine, it seems. It appears to be doing fine without it? bsky.social/about/blog/1...
Find Your Friends on Bluesky - Bluesky
We're introducing Find Friends — a contact import feature that makes it easy to find people you know on Bluesky without compromising your privacy.
bsky.social
January 23, 2026 at 12:57 PM
Huh — bsky has no PYMK ("people you may know") rec sys, it seems? Or? It has a mobile contacts uploader (linked), but it's highly opt-in by design. Lists help some with discovery. But no triadic closure engine, it seems. It appears to be doing fine without it? bsky.social/about/blog/1...
Reposted by Johan Ugander
Reposted by Johan Ugander
Well, no. What reduces productivity is not AI. It's the corporates' quick trading off of experienced humans with AI without a good understanding of when, how, and by whom it should be used.
January 17, 2026 at 3:50 PM
Well, no. What reduces productivity is not AI. It's the corporates' quick trading off of experienced humans with AI without a good understanding of when, how, and by whom it should be used.
Reposted by Johan Ugander
Applications are open for the second annual Disinformation Summer Institute. This is a 4-day, intensive summer institute intended primarily for early career researchers. It will be held at IslandWood. Beautiful place! Applications short and due February 15th, 2026. More info: disinfoinstitute.org
Disinformation Summer Institute (DSI) - Disinformation Summer Institute
Disinformation Disinformation is false or misleading information created and spread to advance policy, political, economic or ideological goals. It is sometimes used by industries, governments, and ot...
disinfoinstitute.org
January 16, 2026 at 10:15 PM
Applications are open for the second annual Disinformation Summer Institute. This is a 4-day, intensive summer institute intended primarily for early career researchers. It will be held at IslandWood. Beautiful place! Applications short and due February 15th, 2026. More info: disinfoinstitute.org
Reposted by Johan Ugander
I had to look up Lizardman's Constant: the 4% of people who will tell a pollster lizard people are taking over the world, ie the minimum answer you will get for even the most absurd question.
"Do you think it would be a good idea or a bad idea for the U.S. to use military force to take possession of Greenland from Denmark?"
Good idea: 4%
Bad idea: 71%
(Ipsos)
4%. He did it. He finally hit Lizardman's Constant.
Good idea: 4%
Bad idea: 71%
(Ipsos)
4%. He did it. He finally hit Lizardman's Constant.
January 14, 2026 at 7:19 PM
I had to look up Lizardman's Constant: the 4% of people who will tell a pollster lizard people are taking over the world, ie the minimum answer you will get for even the most absurd question.
- DeMarzo et al. (2003) "Persuasion Bias, Social Influence, and Unidimensional Opinions", QJE. academic.oup.com/qje/article-...
- DellaPosta et al. (2015) "Why Do Liberals Drink Lattes?, " AJS. www.journals.uchicago.edu/doi/10.1086/...
- DellaPosta et al. (2015) "Why Do Liberals Drink Lattes?, " AJS. www.journals.uchicago.edu/doi/10.1086/...
i feel like it's somehow a very controversial take to say one generally supports immigration enforcement but not shooting unarmed women in the face
January 10, 2026 at 9:51 PM
- DeMarzo et al. (2003) "Persuasion Bias, Social Influence, and Unidimensional Opinions", QJE. academic.oup.com/qje/article-...
- DellaPosta et al. (2015) "Why Do Liberals Drink Lattes?, " AJS. www.journals.uchicago.edu/doi/10.1086/...
- DellaPosta et al. (2015) "Why Do Liberals Drink Lattes?, " AJS. www.journals.uchicago.edu/doi/10.1086/...
I've often joked that as faculty I program in a high-level language called "graduate student". Having tried out Claude Code this morning, I (i) feel extremely at home, (ii) am realizing that research-by-graduate-student is perhaps the original vibe-coding. 1/2
January 8, 2026 at 12:24 PM
I've often joked that as faculty I program in a high-level language called "graduate student". Having tried out Claude Code this morning, I (i) feel extremely at home, (ii) am realizing that research-by-graduate-student is perhaps the original vibe-coding. 1/2
Reposted by Johan Ugander
this is an interesting descriptive statistic for bsky network [pareto principle of production, most people are rubberneckers] that is estimable thanks to atproto's openness. script to make your own is attached - make your own!.
what does this look like for other networks? cc @jugander.bsky.social
what does this look like for other networks? cc @jugander.bsky.social
also that topline follower count is an overestimate for the typical people signed up but disappeared / got put off by the general feed and vibe on here reasons. plotted timestamps of last post for my ~5k+ followers and i'd say ~2k are 'active' [in the last 3mo]
code: gist.github.com/apoorvalal/6...
code: gist.github.com/apoorvalal/6...
January 7, 2026 at 4:21 AM
this is an interesting descriptive statistic for bsky network [pareto principle of production, most people are rubberneckers] that is estimable thanks to atproto's openness. script to make your own is attached - make your own!.
what does this look like for other networks? cc @jugander.bsky.social
what does this look like for other networks? cc @jugander.bsky.social
Reposted by Johan Ugander
Computational Social Scientists in the Nordics, unite!
🇩🇰🇫🇮🇳🇴🇸🇪🇮🇸
The brand new Nordic Society for CSS welcomes all researchers and practitioners based in the Nordics. The Society will promote student mobility, events, and education initiatives.
Join for free: nosocss.org/join.html.
🇩🇰🇫🇮🇳🇴🇸🇪🇮🇸
The brand new Nordic Society for CSS welcomes all researchers and practitioners based in the Nordics. The Society will promote student mobility, events, and education initiatives.
Join for free: nosocss.org/join.html.
January 5, 2026 at 7:57 AM
Computational Social Scientists in the Nordics, unite!
🇩🇰🇫🇮🇳🇴🇸🇪🇮🇸
The brand new Nordic Society for CSS welcomes all researchers and practitioners based in the Nordics. The Society will promote student mobility, events, and education initiatives.
Join for free: nosocss.org/join.html.
🇩🇰🇫🇮🇳🇴🇸🇪🇮🇸
The brand new Nordic Society for CSS welcomes all researchers and practitioners based in the Nordics. The Society will promote student mobility, events, and education initiatives.
Join for free: nosocss.org/join.html.
Reposted by Johan Ugander
Wall Street Journal got an A.I.-run vending machine for their office.
Takeaway: Highly entertaining, but financially disastrous to let a generative A.I. chatbot run your business. www.wsj.com/tech/ai/anth...
Takeaway: Highly entertaining, but financially disastrous to let a generative A.I. chatbot run your business. www.wsj.com/tech/ai/anth...
We Let AI Run Our Office Vending Machine. It Lost Hundreds of Dollars.
An AI agent ran a snack operation in the WSJ newsroom. It gave away a free PlayStation, ordered a live fish—and taught us lessons about the future of AI.
www.wsj.com
December 18, 2025 at 5:24 PM
Wall Street Journal got an A.I.-run vending machine for their office.
Takeaway: Highly entertaining, but financially disastrous to let a generative A.I. chatbot run your business. www.wsj.com/tech/ai/anth...
Takeaway: Highly entertaining, but financially disastrous to let a generative A.I. chatbot run your business. www.wsj.com/tech/ai/anth...
Reposted by Johan Ugander
"Low-rank Covariate Balancing Estimators under Interference"
Always neat to see CBPS in the wild
arxiv: arxiv.org/abs/2512.13944
#statssky #causalsky
Always neat to see CBPS in the wild
arxiv: arxiv.org/abs/2512.13944
#statssky #causalsky
December 18, 2025 at 2:57 AM
"Low-rank Covariate Balancing Estimators under Interference"
Always neat to see CBPS in the wild
arxiv: arxiv.org/abs/2512.13944
#statssky #causalsky
Always neat to see CBPS in the wild
arxiv: arxiv.org/abs/2512.13944
#statssky #causalsky
Reposted by Johan Ugander
Use AI unto others as you would have them use AI unto you
December 16, 2025 at 5:54 PM
Use AI unto others as you would have them use AI unto you
There's an old social media post, lost to time, that goes something like: if you really want to be successful, make sure you wake up every morning and select on the dependent variable. (Guidance counselors hate this one weird trick!) poetsandquantsforundergrads.com/news/which-u...
Which Undergraduate B-Schools Are Most Likely To Produce A Unicorn Founder? This Stanford Prof Has Answers
Dream of building a unicorn? New Stanford research reveals which undergraduate schools most increase the odds.
poetsandquantsforundergrads.com
December 16, 2025 at 2:03 PM
There's an old social media post, lost to time, that goes something like: if you really want to be successful, make sure you wake up every morning and select on the dependent variable. (Guidance counselors hate this one weird trick!) poetsandquantsforundergrads.com/news/which-u...
Reposted by Johan Ugander
We're hiring interns in the Computational Social Science group at Microsoft Research NYC!
If you're interested in designing AI‑based systems and understanding their impact at both individual and societal scales, apply here by Jan 9, 2026: apply.careers.microsoft.com/careers/job/...
If you're interested in designing AI‑based systems and understanding their impact at both individual and societal scales, apply here by Jan 9, 2026: apply.careers.microsoft.com/careers/job/...
Research Intern - Computational Social Science | Microsoft Careers
Research Interns put inquiry and theory into practice. Alongside fellow doctoral candidates and some of the world's best researchers, Research Interns learn, collaborate, and network for life. Researc...
apply.careers.microsoft.com
December 15, 2025 at 4:33 PM
We're hiring interns in the Computational Social Science group at Microsoft Research NYC!
If you're interested in designing AI‑based systems and understanding their impact at both individual and societal scales, apply here by Jan 9, 2026: apply.careers.microsoft.com/careers/job/...
If you're interested in designing AI‑based systems and understanding their impact at both individual and societal scales, apply here by Jan 9, 2026: apply.careers.microsoft.com/careers/job/...
Reposted by Johan Ugander
A new app developed at @princetoncitp.bsky.social allows researchers to construct a large-scale dataset that aggregates individual worker data across many thousands of rides to shed light on the working conditions of rideshare drivers.
Princeton Engineering - New tool drives gig workers toward wage transparency
A new tool developed by Princeton researchers provides gig workers access to aggregate wage data that companies do not provide, a boon for rideshare labor
bit.ly
December 10, 2025 at 8:30 PM
A new app developed at @princetoncitp.bsky.social allows researchers to construct a large-scale dataset that aggregates individual worker data across many thousands of rides to shed light on the working conditions of rideshare drivers.
Reposted by Johan Ugander
The Center for Information Technology Policy at Princeton invites applications for a Postdoctoral Fellow to work with an interdisciplinary team (me, @bstewart.bsky.social, and @manoelhortaribeiro.bsky.social).
Link: puwebp.princeton.edu/AcadHire/app...
Please apply by THIS SUNDAY, Dec. 14!
Link: puwebp.princeton.edu/AcadHire/app...
Please apply by THIS SUNDAY, Dec. 14!
December 9, 2025 at 9:34 PM
The Center for Information Technology Policy at Princeton invites applications for a Postdoctoral Fellow to work with an interdisciplinary team (me, @bstewart.bsky.social, and @manoelhortaribeiro.bsky.social).
Link: puwebp.princeton.edu/AcadHire/app...
Please apply by THIS SUNDAY, Dec. 14!
Link: puwebp.princeton.edu/AcadHire/app...
Please apply by THIS SUNDAY, Dec. 14!
Reposted by Johan Ugander
New paper in Science:
In a platform-independent field experiment, we show that reranking content expressing antidemocratic attitudes and partisan animosity in social media feeds alters affective polarization.
🧵
In a platform-independent field experiment, we show that reranking content expressing antidemocratic attitudes and partisan animosity in social media feeds alters affective polarization.
🧵
December 1, 2025 at 7:59 AM
New paper in Science:
In a platform-independent field experiment, we show that reranking content expressing antidemocratic attitudes and partisan animosity in social media feeds alters affective polarization.
🧵
In a platform-independent field experiment, we show that reranking content expressing antidemocratic attitudes and partisan animosity in social media feeds alters affective polarization.
🧵
Reposted by Johan Ugander
Happy to announce the 2nd edition of our Summer School in Computational Social Science that will take place in the beautiful Villa del Grumello on Lake Como between June 22-26, 2026!
*** DEADLINE FOR APPLICATION: February 15, 2026 (firm deadline) ***
More details here:
css2.lakecomoschool.org
*** DEADLINE FOR APPLICATION: February 15, 2026 (firm deadline) ***
More details here:
css2.lakecomoschool.org
November 27, 2025 at 5:21 PM
Happy to announce the 2nd edition of our Summer School in Computational Social Science that will take place in the beautiful Villa del Grumello on Lake Como between June 22-26, 2026!
*** DEADLINE FOR APPLICATION: February 15, 2026 (firm deadline) ***
More details here:
css2.lakecomoschool.org
*** DEADLINE FOR APPLICATION: February 15, 2026 (firm deadline) ***
More details here:
css2.lakecomoschool.org