YIMBYs as public-hearing NIMBYs: "I'm not opposed to public hearings, I just think we shouldn't have one for this development." "By all means, let's have the public hearing, but only residents in the new building are allowed to speak."

Which way, western man? Abundance vs disinvestment.

If we add one home to the housing stock and it's used for airbnb, does that mean new supply doesn't work? No. If we didn't add that home, the airbnb host would have just used an existing home for airbnb. So new supply frees up the existing home, keeping it in the rental market.

Would industry-wide shocks cause bias in the classic Bartik setup? (y=wage, x=employment) Take LLMs as a common shock to the tech industry; suppose they raise productivity, increasing both employment and wages in tech. #econsky 1/

Vancouver's inclusionary zoning policy in the Downtown Eastside had a 60% (!) social housing requirement. This is obviously miscalibrated, and as you'd expect, only two projects were completed under the policy (and they don't count because they needed subsidies anyway).

Single-family units are not affordable, so why do we allow them?

Moretti 2021 estimates the effect of tech cluster size on patenting. He uses patents per coauthor, ie. splitting credit for a patent across coauthors. Does this make sense? We're not trying to evaluate them for promotion, we're testing whether cluster size causes patenting.

If new condos cause gentrification (rather than vice versa), then what causes new condos?

Who's writing the next fire-induced housing supply paper? C'mon people, it's exogenous variation!

Is this a yimby-phimby crux? Ie. PHIMBYs are happy to use IZ to cannibalize market-rate housing (and raise market-rate rents) if it helps get more subsidized housing. Basically, a transfer from new residents to the poor.

Inclusionary zoning is like the government paying cash for homes to rent out at subsidized rates: if you offer less than sellers will accept, there's no deal. Unfunded IZ imposes a cost on developers, and kills projects.

The economic rationale for IZ does not appear to be constitutional. www.buildingabundance.ca/p/inclusiona...

When housing supply is constrained, increases in demand lead to reductions in the stock of rent-controlled housing. papers.ssrn.com/sol3/papers....

2014 paper shows that supply and demand applies to housing: demand growth increases prices more when supply is more constrained. "The Impact of Supply Constraints on House Prices in England" by Hilber and Vermeulen.

A common economics fallacy is that increasing high-end supply allows low-end producers to raise their prices as well. This is exactly backwards. A thread on price determination. 1/🧵

Extension: use address data to look at displacement as an outcome, and show that a demand shift causes displacement in supply-constrained neighborhoods.

Should upzoning policies allow NIMBYs to opt-out? Let streets exempt themselves from upzoning by supermajority vote, allowing the reform to pass everywhere else instead of risking total failure.

"Upzoning doesn't reduce the price of apartment-zoned land, it increases the price of the upzoned parcel!" "Immigration doesn't reduce wages, it increases the wage of the migrant!"

Market-rate housing is an anti-eviction policy: "landlords of rent-controlled units within 100 meters [of new market-rate housing] are 0.77 percentage points (31%) less likely to evict tenants after new housing is built"

If taller apartment buildings have higher construction costs per square foot, how can increasing density improve housing affordability? Two key points: - prices are set by supply *and* demand - density increases supply 1/🧵

The deeper problem here is that no one cares about the results. Unless research is directly policy-relevant (and being wrong has costs), quality control will always be a struggle. And academics don't want to upset their gravy train, hence, redirecting to "process" instead of facing the problem.

"Don't just read it; fight it! Ask your own questions, look for your own examples, discover your own proofs. Is the hypothesis necessary? Is the converse true? What happens in the classical special case? What about the degenerate cases? Where does the proof use the hypothesis?" — Paul R. Halmos

New vacancy chain paper:

Some thoughts on Samuel's article on the Great Downzoning: worksinprogress.co/issue/the-gr... 1/

Where do you stand on covenants? Should a covenant established in London by William the Conqueror in 1066 be binding today? worksinprogress.co/issue/the-gr...

New version of Kate Pennington's paper on housing in San Francisco, using variation in housing supply from building fires.

New rule: cars have to be Affordable, so that monthly car payments are less than 10% of median income. Any luxury cars that are not sold at Affordable prices will include extra fees to fund Affordable cars produced by nonprofits.

Now that this is sorted, let's see Cook offer a defence of Cook (2014). bsky.app/profile/mich...

A growing city is a constant battle between status-quo-mongers and progress.

If you conflate vacancy chains and filtering, you also mix up how long their effects take. Filtering takes decades, since homes depreciate slowly. But vacancy chains take only one year (as measured in the Finland study).

Inclusionary zoning is justified on economic grounds as a form of value capture. But if value capture is not an accepted legal rationale in the US for requiring subsidized homes, then are there any grounds to justify IZ?

Single-family zoning causes gentrification.

One worry about densifying is that old cheap homes are torn down and replaced with expensive new homes. But adding new homes frees up old homes, via vacancy chains. A new 100-unit building could replace 60 old homes and still break even on the total stock of cheap homes. 1/

Important fact about inclusionary zoning: it's a *partial* value capture mechanism, because it applies only conditional on development. Landowners can avoid IZ value capture by doing nothing, and still watch their land value increase. Land value tax solves this. 1/

Discuss: is it better to under-capture land value, guaranteeing that market-rate housing is built while missing out on some subsidized homes; or over-capture and get the subsidized homes, but at the cost of higher market rents? Ie. costs of false positives vs false negatives.

Video idea: cyclists going through a stop sign at the same speed as a car doing a rolling stop. @ohtheurbanity.bsky.social

New post on inclusionary zoning, for my housing literature review. IZ requires developers to provide subsidized homes in their new apartment buildings. Without providing compensation to developers, this unfunded IZ is just a tax on new housing. 1/

New post on inclusionary zoning, for my housing literature review. IZ requires developers to provide subsidized homes in their new apartment buildings. Without providing compensation to developers, this unfunded IZ is just a tax on new housing. 1/

How to fund subsidized housing using upzoning, a thread. Land value capture works when zoning is (harmfully) a binding constraint on new development. Then, upzoning creates value. Land values rise, because the parcel has more uses. 1/

This paper gives a powerful generalization of event study models to allow an arbitrary number of events, each with a treatment dose of any sign or magnitude. #econsky 1/

Local control over zoning is a government failure, because restrictive zoning imposes a negative externality on non-residents who are priced out. Higher-level governments need to set zoning policy to internalize the externality.

🚨YIMBY research wanted🚨 Show quantitatively how a demand cascade works: when high-end demand increases, it spills over to the low-end market, so both high- and low-end prices increase. Use a Bartik demand shifter for college-educated workers. Measure quality using home age.

One misconception about IZ is that the market-rate homes in an IZ building cross-subsidize the non-market homes. But this isn't how tax incidence works. Developers cannot set above-market rents, because renters would simply find cheaper rents elsewhere. 1/

Moretti 2021 uses an IV for cluster size based on the number of inventors in the same firm in other cities. But this has a coding error, and correcting the error gives a null result. But the idea sounds like shift-share IV, so I tried that, and it works: 1/

LMW are testing whether we find the expected subgroup pattern, when using supply elasticity estimates from the literature to split the sample into Low- and High-elasticity subgroups, and estimating a new elasticity ψ: namely, ψ_L < ψ_H. 1/

LMW are making two contributions: 1) a substantive point about supply elasticities behaving as expected in subgroups. 2) a methodological contribution about identifying relative supply elasticities without a standard instrument. 1/

To people looking for a home today, writes @dannyoleksiuk.bsky.social, it matters a great deal whether that home is built next year, or in ten. Re-legalizing small apartment buildings throughout our cities would create more homes faster. www.sightline.org/2025/10/28/t...

Why not repeat this 1000 times?

Do young people face higher shelter costs than their older compatriots? @lausterna.bsky.social and I look into this question and the underlying mechanisms that can lead to age disparities in shelter costs.

C'mon.