David Perez-Reyna
@davidperezreyna.bsky.social
Reposted by David Perez-Reyna
We built the simplest possible social media platform. No algorithms. No ads. Just LLM agents posting and following.
It still became a polarization machine.
Then we tried six interventions to fix social media.
The results were… not what we expected.
arxiv.org/abs/2508.03385
It still became a polarization machine.
Then we tried six interventions to fix social media.
The results were… not what we expected.
arxiv.org/abs/2508.03385
Can We Fix Social Media? Testing Prosocial Interventions using Generative Social Simulation
Social media platforms have been widely linked to societal harms, including rising polarization and the erosion of constructive debate. Can these problems be mitigated through prosocial interventions?...
arxiv.org
August 6, 2025 at 8:24 AM
We built the simplest possible social media platform. No algorithms. No ads. Just LLM agents posting and following.
It still became a polarization machine.
Then we tried six interventions to fix social media.
The results were… not what we expected.
arxiv.org/abs/2508.03385
It still became a polarization machine.
Then we tried six interventions to fix social media.
The results were… not what we expected.
arxiv.org/abs/2508.03385
"Politicians abandoned such taxes because they did not work."
"[I]mplementing a bad policy in order to achieve a good outcome is rarely a wise approach"
Don’t tax wealth
www.economist.com/fi...
From The Economist
"[I]mplementing a bad policy in order to achieve a good outcome is rarely a wise approach"
Don’t tax wealth
www.economist.com/fi...
From The Economist
October 2, 2025 at 1:05 PM
"Politicians abandoned such taxes because they did not work."
"[I]mplementing a bad policy in order to achieve a good outcome is rarely a wise approach"
Don’t tax wealth
www.economist.com/fi...
From The Economist
"[I]mplementing a bad policy in order to achieve a good outcome is rarely a wise approach"
Don’t tax wealth
www.economist.com/fi...
From The Economist
Mi entrada más reciente en #VocesDeEconomía de @EconomiaUAndes
Colombia necesita volver a ser "aburrida" económicamente. Durante décadas, nuestro país se destacó por baja volatilidad macroeconómica y crecimiento constante vs otros países latinoamericanos. Hilo 🧵
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Colombia necesita volver a ser "aburrida" económicamente. Durante décadas, nuestro país se destacó por baja volatilidad macroeconómica y crecimiento constante vs otros países latinoamericanos. Hilo 🧵
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August 20, 2025 at 4:50 PM
Mi entrada más reciente en #VocesDeEconomía de @EconomiaUAndes
Colombia necesita volver a ser "aburrida" económicamente. Durante décadas, nuestro país se destacó por baja volatilidad macroeconómica y crecimiento constante vs otros países latinoamericanos. Hilo 🧵
1/8
Colombia necesita volver a ser "aburrida" económicamente. Durante décadas, nuestro país se destacó por baja volatilidad macroeconómica y crecimiento constante vs otros países latinoamericanos. Hilo 🧵
1/8
Very nice blog entry by @BrianCAlbrecht
Why do economists have "tariff derangement syndrome"? It's not politics—tariffs violate every principle of good taxation we've learned over the past century.
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Why do economists have "tariff derangement syndrome"? It's not politics—tariffs violate every principle of good taxation we've learned over the past century.
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August 12, 2025 at 12:34 AM
Very nice blog entry by @BrianCAlbrecht
Why do economists have "tariff derangement syndrome"? It's not politics—tariffs violate every principle of good taxation we've learned over the past century.
1/8
Why do economists have "tariff derangement syndrome"? It's not politics—tariffs violate every principle of good taxation we've learned over the past century.
1/8
La próxima persona que lidere Bogotá debería tener entre sus prioridades hacer que la ciudad sea más bonita. Bien alcalda Galán empezar con esta inicitiva
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August 1, 2025 at 9:22 PM
La próxima persona que lidere Bogotá debería tener entre sus prioridades hacer que la ciudad sea más bonita. Bien alcalda Galán empezar con esta inicitiva
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Se puede bajar el gasto público sin comprometer la provisión de servicios públicos. Nueva entrada en #VocesDeEconomía. Enlace abajo
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July 29, 2025 at 6:59 PM
Se puede bajar el gasto público sin comprometer la provisión de servicios públicos. Nueva entrada en #VocesDeEconomía. Enlace abajo
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¿esto es ser neoliberal?
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July 21, 2025 at 4:07 PM
¿esto es ser neoliberal?
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Colombia, te quiero tanto
July 20, 2025 at 6:29 PM
Colombia, te quiero tanto
"The irony of labour-saving automation is that people often stand in the way." From @TheEconomist
July 19, 2025 at 4:22 PM
"The irony of labour-saving automation is that people often stand in the way." From @TheEconomist
Autonomous vehicles should complement public transit, and automating transit should be a goal. Interesting entry by Hayden Clarkin (@the_transit_guy)
July 6, 2025 at 4:08 PM
Autonomous vehicles should complement public transit, and automating transit should be a goal. Interesting entry by Hayden Clarkin (@the_transit_guy)
New paper in @LAJCB_ with Angie Rozada-Najar and Fausto Suaza
*1/6* While manufacturing firms typically exhibit negative assortative matching (productive firms connect with less productive ones), we find the opposite in credit markets.
*1/6* While manufacturing firms typically exhibit negative assortative matching (productive firms connect with less productive ones), we find the opposite in credit markets.
June 12, 2025 at 1:04 AM
New paper in @LAJCB_ with Angie Rozada-Najar and Fausto Suaza
*1/6* While manufacturing firms typically exhibit negative assortative matching (productive firms connect with less productive ones), we find the opposite in credit markets.
*1/6* While manufacturing firms typically exhibit negative assortative matching (productive firms connect with less productive ones), we find the opposite in credit markets.
"Sustained growth, last seen over a decade ago, would provide the sharpest relief."
From The Economist
From The Economist
June 5, 2025 at 8:22 PM
"Sustained growth, last seen over a decade ago, would provide the sharpest relief."
From The Economist
From The Economist
Si queremos ser como Dinamarca, puede ser bueno hacer lo que hace Dinamarca
"Dinamarca aumentó la edad de pensión a 70 años, la cual regirá a partir de 2040" via La República (@larepublica_co)
"Dinamarca aumentó la edad de pensión a 70 años, la cual regirá a partir de 2040" via La República (@larepublica_co)
June 4, 2025 at 1:36 PM
Si queremos ser como Dinamarca, puede ser bueno hacer lo que hace Dinamarca
"Dinamarca aumentó la edad de pensión a 70 años, la cual regirá a partir de 2040" via La República (@larepublica_co)
"Dinamarca aumentó la edad de pensión a 70 años, la cual regirá a partir de 2040" via La República (@larepublica_co)
1/3 Buen blog de Brian Albrecht (@BrianCAlbrecht). Los experimentos de laboratorio del Nobel Vernon Smith sugieren que la economía se puede afrontar como se hace con la física - los estudiantes alcanzan el equilibrio consistentemente.
May 29, 2025 at 6:58 PM
1/3 Buen blog de Brian Albrecht (@BrianCAlbrecht). Los experimentos de laboratorio del Nobel Vernon Smith sugieren que la economía se puede afrontar como se hace con la física - los estudiantes alcanzan el equilibrio consistentemente.
1/7 🧵 New paper with Jorge Tovar (@JorgeATovar) and Tomás Rodríguez. When Colombian regulators introduced stricter liquidity rules (NSFR) in 2020, banks initially increased their market power before competition ultimately prevailed. Here's what happened... 🏦📊
May 29, 2025 at 4:40 PM
1/7 🧵 New paper with Jorge Tovar (@JorgeATovar) and Tomás Rodríguez. When Colombian regulators introduced stricter liquidity rules (NSFR) in 2020, banks initially increased their market power before competition ultimately prevailed. Here's what happened... 🏦📊
El formato de cuadrangulares en el torneo colombiano envía equipos más débiles a Copa Libertadores. Otro argumento para cambiar el formato. Enlace a la entrada con Daniel Franco (@francamente_13) más abajo
May 29, 2025 at 3:28 PM
El formato de cuadrangulares en el torneo colombiano envía equipos más débiles a Copa Libertadores. Otro argumento para cambiar el formato. Enlace a la entrada con Daniel Franco (@francamente_13) más abajo
"we show that counterfactual policies taking into account heterogeneity across sectors can deliver similar benefits from training while inducing less distortions in the firm-size distribution and in the allocation of resources across sectors."
onlinelibrary.wiley....
onlinelibrary.wiley....
May 26, 2025 at 1:45 PM
"we show that counterfactual policies taking into account heterogeneity across sectors can deliver similar benefits from training while inducing less distortions in the firm-size distribution and in the allocation of resources across sectors."
onlinelibrary.wiley....
onlinelibrary.wiley....
"Voters should pay more attention to those with a good record of taking care of the rubbish bins"
www.economist.com/eu...
www.economist.com/eu...
Europe’s mayors are islands of liberalism in a sea of populists
City bosses are the functioning bits of increasingly dysfunctional polities
www.economist.com
May 23, 2025 at 1:08 PM
"Voters should pay more attention to those with a good record of taking care of the rubbish bins"
www.economist.com/eu...
www.economist.com/eu...
Tariffs may help growth in low-debt economies but can destabilize high-debt ones by creating multiple potential economic outcomes, risking self-fulfilling market fluctuations.
www.sciencedirect.co...
www.sciencedirect.co...
On the (de)stabilization role of protectionism
To what extent protectionism affects growth and (de)stabilizes the economies? Although the impact of protectionism on growth has been widely explored …
www.sciencedirect.com
May 4, 2025 at 1:08 AM
Tariffs may help growth in low-debt economies but can destabilize high-debt ones by creating multiple potential economic outcomes, risking self-fulfilling market fluctuations.
www.sciencedirect.co...
www.sciencedirect.co...
Reposted by David Perez-Reyna
I am excited to see whether this will work. Irrespective of that, I think journals should experiment more with the publication process.
March 27, 2025 at 1:41 PM
I am excited to see whether this will work. Irrespective of that, I think journals should experiment more with the publication process.
Standardized tests predict college success better than GPAs at elite schools and may actually help disadvantaged students - contrary to critics' claims.
www.economist.com/un...
www.economist.com/un...
America’s progressives should love standardised tests
New evidence in a long-running argument
www.economist.com
April 16, 2025 at 8:15 PM
Standardized tests predict college success better than GPAs at elite schools and may actually help disadvantaged students - contrary to critics' claims.
www.economist.com/un...
www.economist.com/un...
History shows recessions can boost productivity through 'cleansing' effects, but deliberately engineering one is economic malpractice. A tariff-induced downturn won't replicate the natural selection of market forces—it'll just cause unnecessary pain.
open.substack.com/pu...
open.substack.com/pu...
Will a recession raise productivity?
Probably not. But, historically, U.S. recessions often have.
open.substack.com
April 13, 2025 at 6:03 PM
History shows recessions can boost productivity through 'cleansing' effects, but deliberately engineering one is economic malpractice. A tariff-induced downturn won't replicate the natural selection of market forces—it'll just cause unnecessary pain.
open.substack.com/pu...
open.substack.com/pu...
Reposted by David Perez-Reyna
Just uploaded the newest version of "Trade Deficits with Trade Wars," which I wrote with Jack Rossbach.
papers.ssrn.com/sol3/papers....
Bilateral trade deficits make trade wars more winneable. Action by policymakers is needed to prevent a new world trade collapse.
papers.ssrn.com/sol3/papers....
Bilateral trade deficits make trade wars more winneable. Action by policymakers is needed to prevent a new world trade collapse.
Trade Wars with Trade Deficits
<div>
Trade imbalances significantly alter the welfare implications of tariffs. Using an illustrative <span>model, we show that trade deficits enhance a c
papers.ssrn.com
December 8, 2024 at 3:24 PM
Just uploaded the newest version of "Trade Deficits with Trade Wars," which I wrote with Jack Rossbach.
papers.ssrn.com/sol3/papers....
Bilateral trade deficits make trade wars more winneable. Action by policymakers is needed to prevent a new world trade collapse.
papers.ssrn.com/sol3/papers....
Bilateral trade deficits make trade wars more winneable. Action by policymakers is needed to prevent a new world trade collapse.