We're preparing a bunch of updates for a revised draft next month, so we're happy to hear your comments.

On my end, I'm eager to continue my research agendas as I look for work in academic or policy positions. More on that at my site: tom-cui.com

Thanks for reading!

Text passage: "Our results also have implications for the implementation of the "pro-housing" and "abundance" agendas in the United States. To understand the mechanisms behind the persistent supply effects of 701 assistance, we demonstrated that a historic planning intervention that would have changed interest groups' perceptions of growth has had long-run effects on local innovation in regulatory practices. Piecemeal changes in local regulatory authority do not directly target underlying growth-skeptical attitudes that motivate the adoption of new regula-tions. Policy alternatives could explicitly seek to change the incentives of growth skeptics, such as issuing federal development grants or having federal authorities amortize the infrastructure costs of density (Ozimek and Lettieri, 2024)"

A lot more is in the paper, but last thing I'll note here is that our paper made me think harder about the "abundance agenda"

Our overall story: once 701 set up process giving influence to coalition of empowered planners + growth skeptics, they maintain power by innovating in planning practices

The result is a *path dependence in regulations* between cities, like in the framework of Acemoglu, Egorov and Sonin

Our design also suggests that 701 assistance is linked:

- To more complex zoning!
- With greater adoption of quotas on permits, and of inclusionary zoning!
- To more bargaining for community benefits, where we leverage newspaper reports!

These effects are persistent: the percentage decline in supply is as large after 2000 as they were in the 1970s. Would this be when regulations grew more complex?

We then employ a variety of zoning databases (and set up an AI agent) to get evidence from regulatory text

We estimate that 701-assisted cities had 20% fewer units built in each decade than in their no-701 counterfactual. That's an avg. 13% fewer units built in total between 1960-2010.

Assisted places shifted towards single-family (away from apartments) and more restrictive lot sizes

Text passage: "There is no consistency among the states in the administration of the 701 Program. The types of administrative organization range from independent agencies in some states (Alabama) to agencies which are buried in traditional state departments (the Health Department in one state). State activities range from the provision of professional planning assistance on a broad scale to the processing of applications. The differences in agencies are reflected in a wide variety of staffing patterns, levels of professional expertise, and state funding support."

Text passage: "In Texas none of the four people administering the program are planners, but in most States a planner is in charge or planners are on the staff. Unless the State is playing a role in actually providing technical services to the communities the staffs tended to be small -- between two and five professionals. Most of the States complained that they were understaffed and not able to give the field support that they though desirable. They also felt they were not able to keep close enough check on the work of the consultants in the various communities."

(2) The feds did not send money to cities; that was up to a designated agency for each state.
State capacity ranged between RI's agency - staffed with professional planners - to TX's agency - staffed with one planner under their health dept.

2 quirks -> triple difference design!

But how can we derive a causal effect of the 701 Program? We exploit two quirks with program eligibility:

(1) A population cutoff was in effect; no matter which state you're in, suburbs with > 50,000 population in the last Census were nearly all ineligible.

By tabulating HUD products stored at the National Archives, we confirm that, despite loftier ideals, planners followed a "standard package:"

- Project out population
- Draw up maps of land use, accomodating the growth residents wanted
- Zoning/building codes to enforce land use

We digitize the 701 project directories, counting ~3K cities given grants.

Beyond America's urban core, these cities lacked planning capacity and struggled with post-war suburban sprawl.

701 assistance funded many of the first suburban planners, but not subject to evaluation since the 70s!

Our paper, "Taming the Growth Machine," is available here: tom-cui.com/2025/11/03/s...

We study the 1954 Urban Planning Assistance Program, otherwise known as the "701 Program."

Up to the late 60s, the federal government awarded grants for small cities to match with urban planners.

Primary event study from Bressler and Cui (2025). The effect of the "701" Planning Assistance Program is a 13% reduction in new housing supply per decade .

Why are many U.S. cities building less? Why have they insisted on a "thicket" of regulations that make housing hard to build?

In a new #EconJMP with Beau Bressler (beaubressler.github.io), we study how much of the answer lies with a forgotten federal program that taught cities to restrict growth

Me and the boys watching the global trade war escalate today

In addition, we could recalculate these estimates just for the Southern states - for now, the only place with any hope of even building in this range.

The more interesting question is where exactly do we want the gap to be, between 6-20M. Just from an urbanist perspective, 20M single-family homes would have enormous land use costs.

This is what you'd need for *the free market to lower prices as much as it can* - for existing homes to be affordable to families with more modest incomes than their earlier buyers!

Furthermore, in this world early buyers are free to access bigger McMansions in the periphery.

If you make up these 5-6M units, the affordability issue would look less dire for the dual-earner families struggling to buy homes this second.

The Corinth estimate has a different idea of "needed" - what we'd get if free competition drove prices to their construction costs

The key assumptions about how many units are "needed" here is that it maintains past household formation trends, plus constant vacancy rates.

My interpretation of *how prices look* in this assumed world is that house prices keep rising, but *in line with income growth*.

PSA: A lot of the thread is expanding on what Salim Furth (Mercatus) wrote 2 years ago:

marketurbanism.com/2022/08/05/h...

My preferred method is the approach by Khater et al (2021), updated to '23 data recently. So for me, the shortage "snapshot" now is 5-6M units

brookings.edu/articles/mak...

This isn't the first time we've seen the Corinth/Dante estimates of the U.S. housing shortage - 20 million units!

Sounds like a big number, but it's not a crazy number. The magnitude depends on at what point you'd consider the shortage "closed."

And if I had to make my ideal version of the Canada graph, I'd combine the OECD household data with the Teranet house price index instead.

You can more easily see three "shifts" in the divergence with this anyway: from 2000-2015, 2015-2021 and the post-COVID market.

Then I looked for a more proper measure of income for the context: household disposable income, available in a standard form at the OECD.

The trends match better, at least. But growth is still slower than the OECD data source. From 1984-2022, OECD reports 300% change while the video reports 200%

But the trends don't match! Nothing on FRED could replicate the "income" part.

Here is a zoom-in before the (very real) explosion in Canadian house prices in the last 6 years, showing the lack of a match.

The data actually cites the series on fred.stlouisfed.org they use, which is nominal "Residential Property Prices per capita," replicable by fixing an index value.

At first I thought maybe they went for the next search result on FRED, which is GDP Per Capita. It's not a measure of "income" either

Here's a viral Tiktok chart on housing unaffordability in Canada, but it looked a bit weird to me.

It's not as bad as when a viral U.S. chart compared rent growth with inflation-adjusted income. But here's my look into what is used as "income" here...
www.tiktok.com/@thebeautyof...

at taking charge of both planning "pockets of density" as well as the transportation infrastructure connecting them together.

Greater London outside of the core are some of the most inelastic parts of the country, with inverse elasticities of 15-20!

I'm not convinced Paris's suburbs are big fans of gentle densification and land subdivision either, but I do think the central government there is more adept

This is a bit beside the point, but for a direct comparison with France I found a project estimating local housing supply elasticities for England too. ifs.org.uk/sites/defaul...

You have to take reciprocal of all numbers here, but even the most elastic parts of England have values >= 4!

Heat map of building heights, mapped for London

Heat map of building heights, mapped for Paris

A dataset I really like is the WSF dataset on building area and heights. Here is the *height* data for London vs. Paris, normalized at the same scale. I think it's suggestive that Parisian suburbs are more willing to develop taller on scarce urban land.

geoservice.dlr.de/web/maps/eoc...

Part of what's going on here is that these aren't elasticities estimated separately for each city, but implied elasticities coming out of a cross-metro regression.

Takeaway is still clear though - Paris is a little more housing elastic than avg, driven by having more "regulatory flexibility"