Chris Blattman

@IvanWerning And I wouldn’t normally recommend a French restaurant in Brazil if you’re only there for a few days, but for a cocktail this place is stunning maps.app.goo.gl/v7C5W1vv8MiYUz…

@IvanWerning If you have any interest/experience rock climbing there are some beginner, low intermediate-intermediate options for climbing sugarloaf or Corcovado. Why hike to the Christ statue if you can go semi vertically? If this is your thing I know amazing guides

Excited to be traveling to Rio for a conference and staying a few extra days just for fun and see friends. Incredibly, it's my first time visiting Rio (but not Brazil), so any tips welcome.

I am worried about baiting and switching, which is one reason why I have started making sure all my skills and file systems work seamlessly in both models

Did not see this and stayed up waaaay too late Sunday. So annoying for this to happen twice.

@pedrohcgs @claudeai I stayed up way too late Sunday

@claudeai Where is the reset??? Otherwise, this is kind of useless!!

We're extending Claude Fable 5 access on all paid plans, as well as keeping Claude Code’s weekly rate limits 50% higher, through July 19.

Did not know about the Grubhub+ free subscription.

Friends don't let friends continue to give exams and papers that are not adapted to the current AI landscape (this is AFTER 27 bailed so the reality is even worse) PS Props to students 1, 22, and 31

Why do wars continue when they are so costly? On @NPR, "Why We Fight" author, Prof. @cblatts explains the incentives that can drive conflict, from leaders insulated from the costs of war to uncertainty, misperceptions, and commitment problems. har.rs/4p3VGQq

Knockoff is now live! Filter out the knockoff crap brands on Amazon. Sorry to brands like WNPETHOME, EHEYCIGA, YXYL, LU&MN, JOYIN, TOMY, GODONLIF, YOOJEE, LINGTENG, LANEIGE, VISCOO, BIODANCE, COOFANDY, BALENNZ, TOSY and LUENX. knockoff.shopping

@anup_malani @deankarlan Seatbelts as a norm?

cc @deankarlan @cblatts — is there any field intervention on driving or safety where the behavior stuck after the incentive was withdrawn, or does durable safety always need the money kept on?

Road crashes are a leading killer of young people in poor countries, and most of those deaths come down to how people drive. The obvious fix is to pay drivers to be safer. In a new Kenyan RCT, @davidfromterra, Lane & Kelley (NBER, 2026) find that paying works.

Mexico deserved a win over England. Solution is simple. Claudia Scheinbaum should phone Trump and offer to turn over a drug lord (or Governor Rocha) in return for getting a correction to yesterday’s match.

A Moroccan sultan recognized American independence on December 20, 1777, about six weeks before France did, and a day after Washington's starving army limped into Valley Forge. His name was Mohammed III, and he had never set foot in America. He picked up news of the war mostly from European newspapers and the local French diplomat. He was trying to build Morocco's economy on sea trade, so he sent word to the traders and officials in his ports that ships flying the new American flag were welcome on the same terms as everyone else. That order made Morocco the first country on the planet to treat the United States as an independent country. France did not form its alliance with the Americans until February 1778. America then sat on it for years. The news did not even reach Benjamin Franklin in Paris until the spring of 1778. The sultan offered to sign a full treaty, and Franklin let the letters sit. Mohammed III eventually asked why the Americans had never even thanked him for being the first ruler across the ocean to recognize them. Congress was broke and busy with the war, and it kept stalling. In October 1784 the sultan decided to force the matter. Moroccan ships seized an American trading ship called the Betsey near Tangier and held its eleven-man crew. He did not touch the cargo and did not harm the sailors. He just said the ship and crew would stay in Tangier until the United States sent someone to sign a treaty. It worked. Thomas Jefferson drafted the terms, Thomas Barclay sailed to Morocco to negotiate them, and the sultan approved the Treaty of Peace and Friendship in 1786. Morocco asked for no tribute, the yearly payment most rulers on that coast demanded to leave ships alone. John Adams and Jefferson signed it, and Congress ratified it in 1787, two months before the Constitution was signed. That treaty is still in force today, the oldest agreement the United States has kept unbroken with any country. In 1821 a later sultan gave the United States a building in Tangier for its diplomats, and it is still the only American National Historic Landmark on foreign soil. George Washington eventually wrote to the sultan to apologize for how long the whole thing had taken. The oldest friendship the United States has ever had began with a king it kept ignoring, and a ship he had to seize to get an answer.

Never forget the dogs that don’t bark

Why do hot wars keep happening? @cblatts says first of all, war is rare because it's so costly. When it happens it's because leaders' incentives aren't aligned with the public's, intangible incentives like revenge, uncertainty, commitment problems and misperceptions.

In the state of Wyoming, USA, lies a real hydrological oddity. It's a small stream (creek) that is thought to be one of a just a few examples in the world. It is placed so precariously and perfectly that it's hard to believe it is able to exist. 1/n

Need help with Difference-in-Differences? Meet ChatDID: a GPT specialized in modern DiD methods and the de Chaisemartin–D'Haultfoeuille estimators and software packages. Try it here: chatgpt.com/g/g-6a20206ca0…