Larry Warren

@lfwarren.bsky.social

Senior Economist at the Census Bureau Macro Labor, Market Power, and Firm Dynamics https://www.lawrencewarren.net Views are my own

New BTOS AI Supplement from Census released today. AI use for any business function varies dramatically across sectors and firm size. In AI intensive use sectors, employment-weighted AI use 60-70% -- compared to 32% economy-wide employment weighted. See www.census.gov/library/work...

The Microstructure of AI Diffusion: Evidence from Firms, Business Functions, and Worker Tasks

Using new Business Trends and Outlook Survey data, we find AI use prevalent in large firms and knowledge-intensive sectors; augments tasks; labor declines rare.

census.gov

🚨 Pre-Doc Opportunity at LEHD 🚨 Do you know graduating seniors or recent graduates in economics, math or statistics? The LEHD group at Census is hiring up to 2 positions in this category. Apply following the instructions here: www.census.gov/about/census... If you have questions, DM me!

Economic Measurement and Research Internship (EMRI) Program

The EMRI program seeks to hire interns in economics, accounting and related fields to support the nation’s growing demand for information.

census.gov

A fun/important little piece with @AtlantaFed colleagues. Our survey center asked firms how exposed their supply chain was to imports. More import-intensive firms expect to raise prices more *and* the more their competitors import,the more they'll raise. www.atlantafed.org/research/pub...

Will Tariffs Touch Off an Inflationary Impulse? Business Execs Think So.

This Policy Hub paper uses survey data to explore tariffs' potential inflationary impact and how it could spill over beyond those firms directly affected.

atlantafed.org

ROFL = Real Outliers Fatally Lanced TLDR = Too Lazy; Didn't Research SMH = So Many Hypotheses BRB = Bayes ... Really, Bayes? IMHO = Is My Hypothesis Obvious? DND = Distribution Not Defined FAFO = Fanciful Analysis of Four Observations JC = Jointly Comical NFI = Never Forget Independence

We ran a randomized controlled trial to see how much AI coding tools speed up experienced open-source developers. The results surprised us: Developers thought they were 20% faster with AI tools, but they were actually 19% slower when they had access to AI than when they didn't.

Bild

Just posted updated version of our DID textbook! We now have drafts of all chapters, including the one on general designs! Now you can tell your friends still on X that they are DID-outdated :-) Happy easter for those of you that celebrate it. papers.ssrn.com/sol3/papers....

Credible Answers to Hard Questions: Differences-in-Differences for Natural Experiments

This book introduces applied researchers to modern Differences-in-Differences (DID) methods, that they can use to obtain credible answers to hard causal inferen

papers.ssrn.com

Forthcoming at the Journal of Political Economy: We find that consumer product markups increased more than 25 percent from 2006 to 2019. One contribution is an approach to estimate IO-style models at scale, yielding flexible consumer preferences and estimates of marginal costs.

Bild

It's a very sad day. Just notified that @iza.org is closing its doors as of 31 December 2025. At a time when labor is under attack and technological change moves at an ever-faster pace, I can't help but think that this is a short-sighted decision. My heart goes out to those folks who work there.

We just launched a 16TB archive of every dataset that has been available on data.gov since November. This will be updated day by day as new datasets appear. It can be freely copied, and we're sharing the code behind it to help others make their own archives of data they depend on.

Announcing the Data.gov Archive | Library Innovation Lab

Today we released our archive of data.gov on Source Cooperative. The 16TB collection includes over 311,000 datasets harvested during 2024 and 2025, a complet...

lil.law.harvard.edu

In NYC there is a shop selling cashmere sweaters for dogs, in Amsterdam there is a toothbrush shop. If you are a goth looking for a partner you should move to a city. Finally, there is a forthcoming JET paper explaining this www.sciencedirect.com/science/arti...

Spatial search

This paper considers a random search model where some locations provide sellers with better chances of meeting many buyers than other locations (for e…

sciencedirect.com

Finally out in AEJ:Macro👉 The Evolution of US Retail Concentration w/@dominicsmith.bsky.social Census data👉*National and local* concentration increased 1982-2012 Trends hold for product and industry markets 🔗https://www.aeaweb.org/articles?id=10.1257/mac.20220249 @aeajournals.bsky.social

Front page of the paper "The Evolution of US Retail Concentration" published in the American Economic Journal: Macroeconomics, January 2025.
The Abstract reads: 
Increasing national concentration has contributed to market power
concerns. Yet local trends are more informative about market power in
retail, where consumers have traditionally shopped at nearby stores.
Using novel product-level census data for all US retailers, we find
that local and national concentration increased in parallel and affect
most markets, products, and industries. The expansion of multimar-
ket firms into new markets explains most of the increase in national
concentration, with consolidation via increases in local market shares
increasing in importance between 1997 and 2007. Increases in local
concentration can explain one-quarter to one-third of the observed
rise in retail gross margins.