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Kostas Pelechrinis

@kpelechrinis.bsky.social
307 followers 31 following 695 posts

Information science professor at Pitt | 🏀 analytics at Mavs | Author of Mathletics

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Kostas Pelechrinis @kpelechrinis.bsky.social · 09/10/2026
For those that want to learn a few things and not rely on populists chatgpt.com/share/6ac84f...
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Kostas Pelechrinis @kpelechrinis.bsky.social · 08/10/2026
complex set of ideas as an endorsement of his politics is cherry-picking. But of course we are talking here about populists politicians that'd turn a complicated history into a convenient story that makes their politics sound noble [3/3]
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Kostas Pelechrinis @kpelechrinis.bsky.social · 08/10/2026
"citizen of the world". Ancient Greece and its philosophers held an extremely diverse view on these issues (especially considering that this was 2500 years ago). There were for sure exclusionary ideas, but also arguments for cultural exchange and belonging beyond ancestry. Presenting that [2/3]
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Kostas Pelechrinis @kpelechrinis.bsky.social · 08/10/2026
That Rubio speech at the Pnyx was truly an abomination when it comes to linking his rhetoric with ancient Greece. Of course he did not mention Xenophon who proposed improving foreigners' treatment and granting privileges to attract more of them. Or Diogenes who called himself a [1/3]
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Kostas Pelechrinis @kpelechrinis.bsky.social · 06/10/2026
A slightly different post than what I normally do on this substack but academia is in its steroid era and we need to act faster than what the MLB did... bayesiana.substack.com/p/higher-edu...
bayesiana.substack.com
Higher Education's Steroid Era
Unlike the MLB, colleges need to address their version of ... steroids sooner.
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Kostas Pelechrinis @kpelechrinis.bsky.social · 23/09/2026
Wizard of Boz is the only functioning part of the Steelers offense the last few years. Is he declining? Ofc I did what every fan would: build a Bayesian aging curve (well surface) for kickers. Jury is still out if he’s past his peak but he’s still elite! bayesiana.substack.com/p/growing-ol...
bayesiana.substack.com
Growing old in a young’s man game
A Bayesian look at athletic aging, and whether the Wizard of Boz will decline
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Kostas Pelechrinis @kpelechrinis.bsky.social · 18/09/2026
And here is a writeup of the methods and other stuff 412sportsanalytics.wordpress.com/2026/09/18/t...
412sportsanalytics.wordpress.com
The Spacing Connectome: What can brain science help us learn about basketball?
This one has been long time in the making in terms of being in my mind for years but at the same time not having the appropriate data (or time) to do something with it. But thanks to SkillCorner th…
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Kostas Pelechrinis @kpelechrinis.bsky.social · 16/09/2026
Hopefully I will be able to put together some short writeup for it. These are only illustrative as you cannot get real insights with only 10 games but still interesting imo
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Kostas Pelechrinis @kpelechrinis.bsky.social · 16/09/2026
Thanks to @skillcorner.bsky.social finally we have some tracking data for European hoops! Only 10 games but enough to look at a fun (imo) idea I always had: thinking of spacing through ideas from functional connectivity of brain regions. So I tried out a few things: sites.pitt.edu/kpele/the_sp...
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Kostas Pelechrinis @kpelechrinis.bsky.social · 12/09/2026
Known as the "Windrip" divident since .... 1935. Sometimes the difference between fiction and reality is time .... a long time
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Kostas Pelechrinis @kpelechrinis.bsky.social · 10/09/2026
If you are still not sure about RCV, consider this some (additional) evidence that it can protect us from polarizing candidates. Not necessarily ideologically extreme ones but candidates who generate both intense support and intense rejection bayesiana.substack.com/p/ranked-cho...
bayesiana.substack.com
Ranked-Choice Voting: Against the Tyranny of the Plurality
How RCV can overturn mild pluralities of polarizing candidates in favor of more broadly acceptable candidates
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Kostas Pelechrinis @kpelechrinis.bsky.social · 06/09/2026
With UCL League Phase starting in 2 days I wrote something about leverage, upside and downside risk for each game - with a focus on teams that are projected to be in the bubble of qualifying for the knockout stage (and of course a lot of AEK...) bayesiana.substack.com/p/the-game-y...
bayesiana.substack.com
Information Matters Relative to What You Expected
A Bayesian interpretation of fixture importance through the lens of the Champions League
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Reposted by Kostas Pelechrinis
Adam Kinzinger @adamkinzinger.substack.com · 04/09/2026
The VP wants nothing more than a promotion in 2028. Thursday showed again why he doesn’t deserve it. Upon arriving at the briefing room, it took him only 40 minutes to contradict his boss, insult the American military, and ask the country to feel grateful about gas prices going up. (Link below)
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Kostas Pelechrinis @kpelechrinis.bsky.social · 02/09/2026
😭😂😅
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Kostas Pelechrinis @kpelechrinis.bsky.social · 31/08/2026
20 years ago today I left everything I ever knew behind me & came to California to follow my passion for studying further & doing research in CS. There is not a moment I don't miss Greece but if I had the choice I'd do it over again, even if today my "2006 self" is vilified by a vocal minority.
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Kostas Pelechrinis @kpelechrinis.bsky.social · 30/08/2026
Power laws do not care about your feelings. Which is also why schools should teach actual math instead of fighting over hanging the Ten Commandments on the wall.
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Kostas Pelechrinis @kpelechrinis.bsky.social · 28/08/2026
Knowing how LLMs use probabilistic expressions to communicate uncertainty is crucial as they are becoming our everyday assistants. You can read our preliminary study: arxiv.org/abs/2608.26327 [2/2]
arxiv.org
How Unlikely Is "Unlikely"? Assessing Verbal Probability Perception Across Large Language Models
Large language models increasingly produce and interpret verbal probability expressions, yet whether these expressions carry consistent meaning across models (or match human perceptions of uncertainty...
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Kostas Pelechrinis @kpelechrinis.bsky.social · 28/08/2026
Pythia (Πυθία) was Delphi's oracle delivering max ambiguous prophecies. In 🇬🇷 “possible” is πιθανόν. Phonetically they sound as if they share a root, but they don't. Yet, LLMs act like Pythia: when fed a linguistic probability descriptor & asked to assign a number, πιθανόν exhibits max variance [1/2]
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Kostas Pelechrinis @kpelechrinis.bsky.social · 28/08/2026
Someone is trolling hard in academia. But there is a best case scenario, where we finally move away from using "volume stats" to judge productivity. Sports did it. Time for academia to do it too statmodeling.stat.columbia.edu/2026/08/27/2...
statmodeling.stat.columbia.edu
This University of Chicago business school professor has authored 258 academic papers in 2026 (so far). | Statistical Modeling, Causal Inference, and Social Science
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Kostas Pelechrinis @kpelechrinis.bsky.social · 25/08/2026
Very few clubs embody better the fact that sports teams in Europe are not "franchises" with the strict meaning of the term but are clubs, embedded in the communities they were created binging with them history beyond sports youtube.com/shorts/msOxw...
youtube.com
A Football Club Built to Remember a Lost Homeland #pitchandculture #football#athens #facts#history
YouTube video by PitchAndCulture
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Kostas Pelechrinis @kpelechrinis.bsky.social · 22/08/2026
According to some, on Monday I get back to indoctrinating 20-year-olds on partial pooling, redistribution of probability mass, shrinkage towards the mean and the Bayesian mindset.
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Kostas Pelechrinis @kpelechrinis.bsky.social · 19/08/2026
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Kostas Pelechrinis @kpelechrinis.bsky.social · 15/08/2026
Broadcasters and sports journalists should stop describing basketball as a “chess match”. Chess is a complete info game and deterministic. There is no bishop capturing the rook 37% of the time. Hoops are poker. Stochastic, dynamic with imperfect-information game of repeated best responses. Iykyk 👇🏻
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Kostas Pelechrinis @kpelechrinis.bsky.social · 15/08/2026
And here are some more detailed thoughts about lotteries in research funding decisions. The TL;DR version is that they should absolutely be part of the equation and also that we should elicit slightly different information from the reviewers bayesiana.substack.com/p/the-scienc...
bayesiana.substack.com
The Science Draft
Using Uncertainty, Utility, and a Little Luck to Fund Better Science
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Kostas Pelechrinis @kpelechrinis.bsky.social · 14/08/2026
This isn’t more prevalent bc we dislike admitting how much luck determines outcomes&that even if we've enough info to say a proposal is good, we don’t have enough to distinguish them. We oppose lotteries bc they make randomness that’s already there impossible to ignore www.nature.com/articles/d41...
nature.com
When the best decision is no decision: the rise of randomization in grant funding
If reviewers can’t reliably tell the difference between top grant proposals, why should they pretend they can? A new wave of funders is turning to lotteries to break the tie.
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Kostas Pelechrinis @kpelechrinis.bsky.social · 13/08/2026
Happy International #lefthandersday! Meanwhile, in 1910s Twitter @ CommonSense1912: “Schools now allow children to WRITE WITH THEIR LEFT HAND bc apparently we must accommodate everyone.” @ SaveOurSchools1910: “Only 3% of adults are left-handed. Now suddenly all these children claim to be one? 🤔”
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Kostas Pelechrinis @kpelechrinis.bsky.social · 10/08/2026
One thing students often struggle with as we get deeper into Bayesian statistics is that uncertainty is more than just sampling uncertainty. So I wrote something about the different kinds of uncertainty and why the distinction matters bayesiana.substack.com/p/what-3-doe...
bayesiana.substack.com
What ±3% Doesn't Tell You
Knowing something precisely and being able to predict what it will produce are not the same thing.
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Kostas Pelechrinis @kpelechrinis.bsky.social · 09/08/2026
RIP Don Nelson. We usually throw around the word pioneer too loose today but HE WAS one. Way before “analytics” appeared he was changing basketball; positionless, small ball, point forward, stretch big, space and pace. His impact will endure forever
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Kostas Pelechrinis @kpelechrinis.bsky.social · 09/08/2026
I read a paper today on using AI in the peer review process. It will eventually happen but I put together some thoughts on the model introduced at the paper and my thoughts in general about peer review medium.com/@kpelechrini...
medium.com
AI Can Help Peer Review But Not Until We Fix What Was Broken Before AI Showed Up
I saw this paper today: “Fighting Fire with Fire: Infusing AI into Peer Review to Sustain Quality Scholarship” at Management Science, and…
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Kostas Pelechrinis @kpelechrinis.bsky.social · 08/08/2026
I used Enes Freedom's publicity stunt to showcase how three ideas from intro stats quietly explain how a lot of propaganda works. It is not necessarily about lying, but the illusion of frequency: make something rare feel common by controlling the sample medium.com/@kpelechrini...
medium.com
Creating the Problem, Then Winning the Argument: Enes Freedom, Iran, and the Politics of…
When You Have to Create the Problem to Prove It Exists
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Kostas Pelechrinis @kpelechrinis.bsky.social · 03/08/2026
It is mind boggling seeing people still claiming vax didn’t work, or measures like masks and social distancing infringed their “freedom”. Man we are beyond cooked. We are in the oven 4 hours after cooking was done
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Kostas Pelechrinis @kpelechrinis.bsky.social · 03/08/2026
avoid the “complexity” of the probabilistic message. People want to hear yes or no, not maybe or likely. The best you can do is explain it and hope for the best. But having said that prob thinking is an absolute must!
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Kostas Pelechrinis @kpelechrinis.bsky.social · 03/08/2026
Since midterms are coming and we are back at the “we were scammed with the jabs”, I think this points to another example of why probabilistic thinking is a must. Fauci et al. completely botched the communication around the vaccines. And I think this might have been deliberately on their side to
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Kostas Pelechrinis @kpelechrinis.bsky.social · 31/07/2026
You used to know elections were approaching when cities suddenly became massive construction sites (ofc only for the work to stop once the election was over). Now a few minutes on social media is enough to see the politics of fear in full swing and know elections are coming
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Kostas Pelechrinis @kpelechrinis.bsky.social · 30/07/2026
This is a pretty interesting experiment. It illustrates why human expertise remains important in causal data science. Without informed guidance an LLM may/will rely on prior/recalled knowledge rather than reasoning from the data. erdogant.substack.com/p/can-llms-d...
erdogant.substack.com
Can LLMs Discover Cause and Effect? A Benchmark Against Bayesian Models and the Problem of Knowledge Leakage.
LLMs may generate convincing answers, but how trustworthy are the results? Hidden knowledge acquired during pre-training can influence conclusions without the user realizing it.
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Kostas Pelechrinis @kpelechrinis.bsky.social · 23/07/2026
Meanwhile the true rate is about 0.03%. This is a 566x delusion that can clearly affect views....Youth and kids sports exist for kids to have fun, play with their friends, socialize and exercise. Very few kids survive true competition. [5/5]
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Kostas Pelechrinis @kpelechrinis.bsky.social · 23/07/2026
beachfront property in Pittsburgh to sell you 4. Parents are trying to live their own failures and dreams, thinking their kids are going to be professional athletes, and somehow a trans kid is going to hold them back. 17% of the parents think their kids are going to be professional athletes. [4/5]
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Kostas Pelechrinis @kpelechrinis.bsky.social · 23/07/2026
basically it is a non-issue at that level 3. If you really believe that a kid would simply say "I will become trans, so I can compete with women and win medals" (or "...to sneak in women's locker rooms") when everyone knows the bigotry coming from the likes of Travis etc. then I have a [3/5]
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Kostas Pelechrinis @kpelechrinis.bsky.social · 23/07/2026
has been mocking women's sports for as long as I remember. It's a culture war to score points with the MAGA base 2. Provable with numbers we are talking about a rate of 10-in-510000 when it comes to elite levels (NCAA) and even less when we are talking about professional leagues. So [2/5]
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Kostas Pelechrinis @kpelechrinis.bsky.social · 23/07/2026
With the usual suspects like Gaines and Travis parading Cunningham's comments, it's worth putting a few things in perspective for those that like to put their brains to thinking rationally: 1. This whole thing has nothing to do with women's sports and supporting women. For god's shake Travis [1/5]
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Kostas Pelechrinis @kpelechrinis.bsky.social · 18/07/2026
Argentina is known for its approachable yet age-worthy wines. Clos de Rosario Vintage 1987 is their best 🐐 🍷 Enjoy a glass with all publicly available #Messi goals (thanks to StatsBomb) You can also interact with the visualization here: sites.pitt.edu/kpele/messi_...
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Kostas Pelechrinis @kpelechrinis.bsky.social · 18/07/2026
All (the ones publicly available from Statsbomb) of #Messi 's career goals in an interactive viz. If you have all the goals, you can upload a json file with the data (format described and file is not stored anywhere on the server) and see the new viz. sites.pitt.edu/~kpele/messi...
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Kostas Pelechrinis @kpelechrinis.bsky.social · 16/07/2026
ok everyone is talking about Messi, but after the 2018 world cup I was invited and gave 3 seminars on sports and football analytics in Argentina. Since then they have won everything and playing again at the final (which I hope they win also). Coincidence? Well, yes 😂 But had the 6-7 meme well ahead😅
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Kostas Pelechrinis @kpelechrinis.bsky.social · 11/07/2026
This football myth has beeb busted before afaik in many different ways but here is one with Bayesian hierarchical modeling 412sportsanalytics.wordpress.com/2026/07/11/b...
412sportsanalytics.wordpress.com
Big Man, Small Edge: What the Data Actually Say About Tall Goalkeepers and Penalties
Every pundit has said it at some point during a shootout: “you want a big goalkeeper back there”, “height fills the frame”, “height makes the target look smaller&#8221…
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Kostas Pelechrinis @kpelechrinis.bsky.social · 07/07/2026
1987 Clos de Rosario 🐐🍷
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Kostas Pelechrinis @kpelechrinis.bsky.social · 06/07/2026
RBFA should do the funniest thing ever: challenge birthright citizenship in the US. It will short circuit the whole WH 😂 /s
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Kostas Pelechrinis @kpelechrinis.bsky.social · 29/06/2026
Well since I am not travelling to Greek islands again this summer, how else would I feed my crave but with an analysis including them. And it turns out that nature is the worst gerrymanderer medium.com/@kpelechrini...
medium.com
The Gerrymander Archipelago
I applied the same math US courts use to detect gerrymandering to the Aegean and Ionian. The results are alarming. The culprit has been…
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Kostas Pelechrinis @kpelechrinis.bsky.social · 28/06/2026
static.klipy.com
Randy Marsh Demands: We Need It Now!
ALT: Randy Marsh Demands: We Need It Now!
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Kostas Pelechrinis @kpelechrinis.bsky.social · 26/06/2026
It seems that my suggestion for solving the STEM pipeline issue might have to be the standard for ALL students if this trend keeps up. Education is in a really sad state... medium.com/@kpelechrini...
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Kostas Pelechrinis @kpelechrinis.bsky.social · 25/06/2026
Strange. I thought spreadsheets were supposed to be a coping mechanism for people who can’t play. www.wsj.com/sports/socce...
wsj.com
The Harvard Data Nerd Defending America’s Goal at the World Cup
Matt Freese, who holds an Ivy League economics degree, came out of practically nowhere to secure the job as the U.S. national team’s starting goalkeeper—and his analytical approach has been integral t...
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