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January 29, 2024 by Jason Barr 3 Comments

The Plot Thickens (Part II): Sticky Gotham

Jason M. Barr January 29, 2024

[Coming May 14, 2024: Cities in the Sky: The Quest for the the World’s Tallest Skyscrapers (Scribner Books)]

What’s driving the affordability problem in New York City? If you ask a random person on the street, they’ll blame developers, who seemingly only build luxury towers for the well-to-do. But the developer might say that the land values are to blame—to recoup the high cost of the land and expensive construction costs, the only profitable new development is on the high end.

As discussed in the previous post, expensive land values are a symptom—not the cause—of a larger problem—the lack of land being offered up for redevelopment. The high land values signal New York’s “scarce land policy.” The lack of in-fill and densification is due to a series of government-made and natural frictions. Here we dive into more details about the nature of these frictions and the policies needed to “loosen” things up.

Gummed-up Gotham

First, let’s review the facts on the ground. If we look at block-level changes in the number of housing units in the last two decades, we see a very sticky Gotham. Nearly one out of three (31%) blocks with at least one housing unit in 2004 had no change in the number of units since then. 57% of blocks had zero, plus or minus one unit. More broadly, nearly half (48%) of the city’s blocks had no change or lost units. No matter how you slice and dice it, about half of the city’s residential blocks remained frozen in the last two decades.^[1]

Taking a helicopter view of New York’s 59 community districts, nearly two-thirds grew their housing by less than 10%, while only four had a two-decade growth rate of 30% or more (see figure below). In short, only four community districts did any real heavy lifting, and one was lower Manhattan, where Art Deco office towers were converted to apartments.

Block-level Changes in Housing Units. The majority of New York City Blocks either lost or had no change in units between 2004 and 2022. Note blocks shown are ones that had at least one unit of housing in 2004. Source NYC PLUTO file.

Should I Stay or Should I Grow?

New York City has about 859,000 land parcels (and the number has been steady over the last few years). One metric of what’s offered for development is to count the number of new building permits for housing.

In the last five years, the average number of permits issued is about 1,500 per year, and the city has completed, on average, about 25,000 per year or about 250,000 gross new housing units per decade—without accounting for teardowns, unit mergers, or conversions to other uses. 2023 was a terrible year, with less than 10,000 units permitted. A back-of-the-envelope calculation suggests that the probability that any lot “gives itself up” for redevelopment is about 1,500/859,000 = 0.17%.

One year ago, Mayor Adams proposed adding 500,000 units in the next decade which would represent a nearly 250% increase in the number of units built each year and more than double the number of permits issued. But we can’t get to abundant housing if the land is iced.

Give Yourself Up

The aim of this post is to estimate the probability or likelihood that a block generated at least one new unit of housing over the five years from 2018 to 2022 based on the block-level characteristics that existed as of 2016.^[2] In short, the exercises aim to look at what features of New York’s lots and blocks are incentivizing or disincentivizing new construction. (The data sources and processing are here.)

This statistical exercise does not consider things like tax abatement generosity or broader macroeconomic issues like rent values. Rather, the analysis considers what is about the lots and blocks themselves and the buildings on the lots that would suggest why a lot is given up. If we genuinely want to make housing more affordable, we need to know what’s going on and focus on “loosening” the lots.

Probably?

The data reveal that the probability of a city block producing at least one unit of new housing (given it had at least one unit previously) during the period was about 13% or about 2.6% per year. These blocks produced about 48,000 new units or about 9,600 per year (which also suggests that about half of all new housing built today is on formerly commercial, industrial, or vacant land).

So, let’s say, for example, to get to more abundant housing, we want to double the probability that a block produces at least one unit of new housing. What would it take? In other words, how do we go from a five-year probability of 13% to, say, 25%?

Drivers of the Gap

As discussed in the prior post, the underlying economics of cities and land use suggest several factors that drive the likelihood that a lot will have redevelopment. I defined the “Development Gap” as the potential profits obtained from densifying a lot versus the profits from keeping the lot as it is. The higher the Gap, the more likely a lot will gain more units. What are those elements?

Centrality

The first is centrality. Since housing prices are higher in the center because of the greater demand to reside there, the Gap will be higher in more central locations (here, I define the city center as the Empire State Building).

Zoning

Next is zoning regulations—the more stringent the regulations, the lower the Gap because the redevelopment floor area is capped to something that would not produce an income above the cost. In New York, building density is regulated by caps on the Floor Area Ratio (FAR), which limits total floor space per square foot of lot area. In many instances, a current building’s floor area is greater than the allowable maximum for a new structure, making redevelopment virtually impossible.

Current Building Density

The greater an existing building’s density and height, the less likely the lot will be redeveloped because of the difficulties associated with emptying and tearing it down.

Rent Stabilization

Rent stabilization is a mixed bag in terms of incentivizing redevelopment. On the one hand, it lowers the actual income relative to the market-rate potential. On the other hand, it’s hard to redevelop when it’s difficult to get tenants to move. So, the net effect is unclear a priori.

Ownership Status

Turning to owner-occupied units, we expect those to be much less likely to be redeveloped. In the case of condos or coops, all the tenants would have to agree to such an idea—nearly an impossibility. In the one- or two-family-home case, homeowners are less likely to move, given the costs of selling their house and buying a new one. Additionally, homeownership is highly subsidized to encourage long-term tenancy. So, homeowners, by their very nature, are households that are less likely to move.

Landmarking and Historical Districts

Landmarking and historical districts reduce redevelopment because they make it illegal to make large-scale changes to the affected properties.^[3]

Call Me Maybe: The Evidence

Policy Created Frictions

Turning to the statistical (regression) results (here), I find that the “Development Gap Theory” is strongly supported. Scarce housing in New York is not a mystery: Economics matters and the way to get more supply is to understand the factors that disincentivize new housing—across the entire city.

Regarding policy decisions, zoning strong impacts redevelopment. For example, the analysis reveals that doubling the allowable FAR on a block (e.g., from 1 to 2 or 2 to 4) increases the probability of redevelopment in five years by about ten percentage points. Relatedly, the more lots on a block above the allowable FAR, the lower the probability of redevelopment, as expected. Each additional ten buildings over the allowable limit reduced the likelihood of redevelopment by about 1.5 percentage points.

As expected, the statistical analysis shows that the more buildings that are landmarked or fall within historic districts, the less likely a block will have new residential buildings five years later, similarly for blocks with many owner-occupied units.

Interestingly, a block with more rent-stabilized buildings does not affect the probability that a block will create at least one unit. This likely reflects how rent stabilization impacts the Gap, as discussed above.^[4]

Natural or Structural Frictions

But policy decisions about land use are not the only game in town. As cities age, they create their own “natural” or “structural” frictions. In principle, the city’s grid can determine the shape of the blocks and the number of parcels on each one. Over time, ownership can become more dispersed, making combining lots harder. Before zoning, many blocks had buildings with much greater densities. Plus, location matters—places where prices are lower are less likely to redevelop simply because of the economics.

The statistical results here strongly suggest that these historical factors matter. Buildings further away from the center, on average, are less likely to add new housing simply because of the lower revenues these properties will generate. If two blocks are similar, but one has twice the building floor area, its redevelopment probably drops by four percentage points.

Interestingly, larger blocks are less likely to have redevelopment activity, while blocks with more lots will likely see more redevelopment. The reason for these findings needs to be explored further, but having more lots on a given block means more decision-makers, and thus, it is more likely that some of them will redevelop their properties. Lot size matters, too. If a block has too many very small lots, it’s less likely to see redevelopment.

Housing Stock Growth By Community Districts (2004-2022). About two-thirds of Community Districts added less than 10% to their housing stock in two decades. Source NYC PLUTO file

Playing the Odds: Getting to Abundant Housing

Given the findings, what might the City do to double the probability of getting double the housing?

Upzoning

Let’s start with zoning. The evidence worldwide shows that upzoning works, and the data analysis here also supports that. I found that stringent zoning strongly reduces the probability that a block will build new housing.

Say the city doubles the allowable floor area ratio (FAR) on each block and that none of the buildings are above the allowable floor area. This change would increase the five-year citywide probability of redevelopment by an additional ten percentage points. So, doubling zoning gets you about three-quarters the way there.

Taxing and Subsidies

Construction subsidies or tax abatements can help loosen up the lots, but they need to be more targeted to “stickier” areas. They should be based on the distance from the center or the neighborhood’s income level. Lower-income neighborhoods should get more generous subsidies, as should those further away from the center. For single-family districts, the city should give tax abatements for ADUs or converting single-family housing into two-family housing.

New York City has over 565,000 one- and two-family homes. As a thought experiment, if each added one more unit—an Accessory Dwelling Unit (ADU) or new internal unit via subdivision—the city could get to Mayor Adam’s target of 500,000 new units without a single teardown.

More broadly, a land value tax that taxes land values higher than the value of the building is a good way to disincentivize the holding of under-developed plots.

Land Banking

The City can’t do much about block sizes and current building densities. However, it can impact zoning regulations and encourage land assembly or land banking. The City would buy up underutilized lots and then sell them to other property holders on the block creating larger lots that would be more profitable to redevelop.

A City of Yes?

Mayor Adams likes to use the phrase “City of Yes” to pitch his plans for new housing, but today Gotham remains the “City of No.” The road to abundant housing is clear:

Relax stringent zoning rules (especially near transit lines),
Subsidize housing construction costs in lower-income housing neighborhoods and those in “low Gap” neighborhoods.
Allow one- and two-family homes to add one or two more units.
Create a land value tax.
Establish a City authority that buys land to encourage land assembly or sells ground leases for affordable development.

Despite widespread supply skepticism, the results in this post show that the problem of affordable housing is not one of economics—it’s one of politics. Releasing the land will get us there if the political will emerges to allow it. It’s time to unstuck Gotham.

Continue reading Part I of the series here.

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^[1]These statistics are based on lots that had some housing units in 2004. Thus, we are not talking about the conversion of industrial or commercial land to residential.

^[2] I repeated the exercise to see what prompts a block to build ten or more units of new housing. Results are broadly similar. See here for the results.

^[3] I want to be clear, I’m not opposed to landmarking and the creation of historic districts. However, it’s important to recognize that they reduce a city’s ability to provide more housing supply.

^[4] However, the more rent-stabilized buildings on a lot, the more likely it will be redeveloped for ten units or more. So, it suggests that rent stabilization is promoting redevelopment in denser, more central places where the Gap is stronger.

January 10, 2024 by Jason Barr 1 Comment

The Plot Thickens (Part I): Do High Land Values Reduce Housing Affordability?

Jason M. Barr January 10, 2024

The billion-dollar question: What’s driving the housing affordability problem in large cities like New York? When looking to cast blame, people naturally pick developers. Clearly, the conventional wisdom goes, they are making the problem worse because all they do is build unaffordable luxury high-rises.

Developers will argue, however, that given the high cost of land, the only way to make their investments work is to create a building that will produce enough revenue to pay for itself and the cost of land. Thus, high land values drive the affordability problem.

The “blaming the land” idea was recently stated in a blog post on New York’s housing affordability crisis by Sam Stein in The Architect’s Newspaper, which cites my work and motivates me to write this blog post. Regarding the housing affordability problem, he states,

It’s not just the price of housing, it’s the price of land.

The price of housing is what we all see, but the price of land is a big part of what’s hidden behind it. A 2018 study by Barr, Smith and Kulkarni in the journal Regional Science and Urban Economics found that since 1993, Manhattan’s land values have increased at a compounding annual rate of 15.8 percent, far faster than the rate of job or population growth. By 2014, Manhattan’s land value—separate from the value of anything on top of it—was estimated at $1.74 trillion.

Land Values

But are high land values, in fact, causing the housing affordability problem? The answer is not as straightforward as it might seem. Land is a different type of product—it’s immobile, and its value is determined as much by what’s around it as by anything else.

The substance below the ground provides no actual benefit. Manhattan’s bedrock schist, for example, is nearly valueless. You can’t use it to make countertops or jewelry, and there are no veins of gold. Very rarely, it’s used for building facades—but they are the exception that proves the rule. The soil is not worth much more, either. Brooklyn’s farms no longer produce the cabbages that were made into soups and sour kraut in the Lower East Side.

So, today, the land has only two features of value in the space-time continuum: gravity—you can stand on it—and geography—it has coordinates. Before we blame land for the affordability crisis, we need to understand what drives land values in the first place.

Let’s say a large, choice lot in an urban neighborhood is put up for sale for redevelopment. What would a developer be willing to pay it? Or more broadly, what is the market value of that sliver of the city?

Show Me the Money

Like any asset, the market value of land is determined by the potential net income that it can generate. Would-be developers first perform a series of cost-benefit estimates from erecting various types of buildings at different heights or densities.

A taller building will generate more revenue than a shorter one. But a shorter building is cheaper to build. Even though a taller building might produce more income, the extra cost might reduce the profits. Wealthier people will generate more revenue than those with less income. But they might not be willing to pay to live in a neighborhood far from the center. So, the maximum income might come from those in the middle-income range.

Billionaires’ Row in New York City. Photo by Jason Barr.

Do You HABU?

After weighing the trade-offs from various hypothetical structures, the developer will determine what’s called the “highest and best use” (HABU)—the height, quality, and expected occupants that will maximize the return from the project. Generally speaking, taller buildings will be erected in the center for higher-income residents and lower-rise buildings will be most profitable as one moves further from the center.

But where do land values fit in? The market price of land—what emerges in the competitive bidding process to take title to the property—is determined after the highest and best use is calculated. In other words, a developer will pay a price for the land such that, once redeveloped, the new building will cover the land and construction costs and provide extra for a satisfactory return on investment.

Society Determines Land Values

So yes, to the developer land is an expense, but one that is essentially determined based on what the developer “should” construct. The marketplace—and, more broadly, society—determines the value of the land. So, fundamentally, high land values are not the driver of housing affordability. Rather, the value of land tells the developer what “should” be done with the lot. And if the land values are high—it suggests that its most profitable use is not affordable housing.Of course, this is galling to many, especially when they see older, charming, or historic buildings being torn down by high-rise condos for the ultra-rich.^[1]

Digging Deeper into the Land

However, despite the market determining land values, there is no perfectly free market in land. Instead, land is a highly regulated commodity, limiting what it can be used for. We need to dig a little deeper.

First is zoning. A large body of research shows that overly stringent zoning or land-use regulations will reduce building heights below what the HABU determines. For example, if the most profitable use of a lot is a 20-story tower, the zoning rules require it to rise no more than ten floors, thus lowering the profit from development. If zoning reduces a building to less than its HABU, land values will fall.

Another element is construction costs. The higher they are, the smaller the profit from erecting buildings and thus the lower land values. Big cities like New York and San Francisco are among those with the highest construction costs in the world.

Land valuation methods thus produce a paradox: zoning and higher construction costs, all else equal, reduce land values—and in big cities, which have some of the most stringent and highest costs, we would expect the land value to be lower, not higher. So, what gives?

The Plot Thickens

So far, we’ve been discussing the market for an individual parcel that’s put up for sale. But the solution to the paradox exists by moving up to the wider land market and looking at the total number of lots offered up for redevelopment each year. Here’s where the real problem lies.

The big takeaway is that government rules, NIMBYism, and other historical barriers to redevelopment create land scarcities, and this land scarcity creates unnaturally high land values, which, in turn, incentives the construction of mostly luxury housing. The demand to live in big cities is so strong, but the number of lots available for redevelopment to accommodate this demand is highly limited. The high land values problem is thus due to the bottleneck in land provided for new housing.

Not the Scarcity You Think

However, I want to be clear about what I mean by land scarcity. New York and other cities are not running out of land—there will always be the land needed to accommodate nearly any population. New York City, however, is placed under an “artificial dome” because its zoning limits its population growth—particularly in the suburban areas. The issue is thus not the total amount of physical land per se but rather the amount made available to accommodate a growing population.

Technological improvements in construction and design mean there’s always the possibility of making more land—in the sky. It’s worth noting that in 1900, a tall building was twenty stories. Today, “tall” is generally considered above 50 stories. And since 2001, nearly 100 residential buildings of 70 stories or taller have been constructed around the world. Brooklyn, for example, just welcomed a new 93-story tower.

Stay or Go?

The way to understand the supply of developable lots that come on the market is to look at the net value of these lots relative to the value of remaining as it is. In other words, we can imagine that every lot in the city has two values—one based on its current use and the other based on its HABU if redeveloped.

We can call the difference between the profits from HABU and its current use the Development Gap. The larger the gap, the more likely a lot will be offered up for redevelopment with more housing units. The point is that the supply of lots is based on the difference in profits from the current use versus the HABU, and as this difference rises, so does the likelihood of redevelopment. In a given year, if many redevelopment lots are offered for sale throughout the city, then in five years, the housing market will be flooded with new units. So, what determines the size of the Development Gap? Let’s review the key elements.

Allowable Floor Area versus Current Floor Area

The larger the difference between the building’s current density and allowable density from the zoning rules, the greater the gap and the more likely it will be redeveloped. Conversely, the greater the existing building height or density, the less likely it will be put for redevelopment.

In New York City, for example, 36% of residential lots have their current floor areas at or more than the rules allow. They are essentially undevelopable since building a new structure would have to be smaller than the current one. Nearly 60% of residential lots have floor areas that are either above the allowable amount or within 25%—making redevelopment unlikely.

More broadly, the greater the density of the building, the less likely it will be redeveloped, independent of the zoning rules, due to the high costs of emptying the building, tearing it down, and erecting something more profitable in place. This is a kind of “natural friction” that all cities have to deal with, and it suggests that a critical role of housing policy is to “grease the wheels” to undo the stickiness preventing the construction of more housing. Nimbyists, of course, do not approve of these policies because they reject whole-scale changes to their neighborhoods.^[2]

Domed Gotham. Nearly 605 of parcels in New York are at or near their maximum development density, rendering densification unlikely or impossible. Source: NYC PLUTO.

Amount of Land

Even though a well-built city will never run out of land, the total land area does matter. Cities that have more water bodies, more rugged terrain, or steeper hills will be more expensive than those whose surfaces are large, featureless plains. It’s simply a matter of access to more developable lots. These barriers can be overcome with investments in high-speed transport, which can extend the urban area and provide more land for the city.

However, government-created policies can act as a barrier to urban expansion. Some cities create vast greenbelts that reduce developable land. Other metropolitan areas, like New York, create de facto greenbelts because local town zoning ordinances frequently have minimum lot sizes and rules on maximum lot coverage. And they permit apartment buildings in all but a few tiny zones. In essence, suburban communities erect invisible walls that prevent a city from building more housing.

I also want to be clear. I’m not opposed to the region creating large natural woodlands or parks—urban nature is vital. But greenbelts remove land for housing. For example, the Metropolitan Green Belt around London was created to check population density. In 1940, chief New York City planner Rexford Tugwell proposed a greenbelt for New York for a similar reason. However, using greenbelts and other anti-densification measures to stop population growth is antiquated, outdated, and harmful to urban growth and well-being.

Current Income versus Future Income

All else being equal, if redevelopment generates a much higher revenue stream than a building’s current use, it will encourage the parcel to be offered up (assuming the zoning allows it). So much high-rise development takes place in central areas because the income from new construction is so much higher than the income from current buildings, and central-city zoning tends to be much more generous than out in the suburbs. Given the national and international demand for a place in the center, it naturally means a higher gap and, thus, more new construction.

However, there is a large unmet demand for less fancy housing along mass transit lines in the suburbs. Just look at Yonkers, north of the Bronx border, which has big swaths of vacant, formerly industrial land along the Hudson River. It is finally being converted to housing for the “missing middle.”

Rent Controls

Many large cities have some form of rental price controls, which limit rent increases and give tenants the right to stay in their units if they remain in good standing. However, rent stabilization is a double-edged sword, when it comes to redevelopment. When a building is filled with rent-controlled tenants, it reduces the income relative to HABU income and thus incentivizes redevelopment, which are usually market-rate units.

But tenants’ rights to stay also mean that the structure will remain occupied as long as tenants want to stay. Developers can buy out (or, unfortunately, engage in “slumlord” practices) to get tenants to leave, but this will increase the costs and reduce the gap, lowering the likelihood of redevelopment.

Red Tape and Construction Lags

Red tape is one of the most significant problems that reduce the Development Gap. Big cities often place before the developer a big list of boxes they must check and long waiting times before all the permits are given. The delays are even longer when dealing with housing subsidies, novel building designs, or projects requiring a zoning change.

One recent study for Los Angeles looks at permitting times within LA’s Transit-Oriented-Communities (TOC) program, which encourages redevelopment of multifamily housing around transit lines. The authors found that the median time to permit an as-of-right project was 1.18 years and 1.35 years for those requiring additional permissions.

This was just the median time, which means that 50% of the respective projects required longer waiting times for approval—and in a program designed to speed up housing construction. Then consider that at least two to three more years are needed to build out and fill up the building. Before the project begins, at least one year is required to raise funds, design the building, and perform market studies. So, roughly speaking, the project from planning competition for multifamily can take at least four years if things go smoothly—hardly a way to deliver needed housing now.

Property Taxes

If a property’s real estate taxes rise with new construction, the higher costs can provide a redevelopment disincentive. Many cities offer real estate tax abatements to promote new construction. Sam Stein blames residential tax abatements for, ironically enough, harming affordability. He argues that available tax breaks wind up raising the cost of land—because they make redevelopment more profitable—eroding the very benefit they were designed to provide.

But this is not quite true. In a direct sense, the higher price of land is a higher cost, and tax abatements are capitalized into land values. But at the same time, they reduce operating costs for new construction and thereby generate more supply, which can help keep prices in check.

But let’s be clear: Abatements are not causing the affordability problem—higher land values incentivize taller buildings and provide more units. To the extent that abatements also requires set-asides for affordable units, then some go directly to those who need them the most.^[3] But if you permanently eliminate tax abatements, you will not solve the housing affordability problem. Yes, land values would decrease, but new construction would not go up unless you released the other frictions preventing redevelopment.

The “Astor Index.” This index shows the relative price of vacant land to land with buildings on it for Manhattan. In the 21^st century, vacant land has sold at greater and greater premium because so few lots are offered up each year for redevelopment. Source: here.

How to Make Housing More Affordable

The simple means to improving affordability is that more lots need to be offered up for redevelopment for buildings with more units, particularly outside the city center where housing demand is local and with more moderate incomes.

Transit-oriented Development

As discussed in other posts, the lowest-hanging fruit is to rezone neighborhoods near transit spots to create transit-oriented development. It seems a no-brainer, yet NIMBYism is preventing planning officials from upzoning these places. A year ago, Mayor Kathy Hochul submitted a plan to upzone neighborhoods near transit stops. It was quickly rejected by the state legislature—particularly those representing suburban neighborhoods. In 2024, she’s going to try again, but let’s see….

Vacancy Targeting

A useful strategy for cities to employ is what I call vacancy targeting. That is, when housing vacancy falls below a low number, say 5%, in a particular neighborhood, the city should—automatically—enact policies that incentivize more construction. This can include targeted construction subsidies and even the building of new public housing (which would be open to a wide range of income groups).

The point is ensure that housing gets built where needed and wanted the most. To make such a strategy work would also require cities to have ready-to-go plans for increasing their local service provisions, such as increasing school capacity and upgrading local parks. If central neighborhoods had higher vacancy rate, voucher programs for the those with low-income would worker better, given the lower competition among renters.

Land Taxes

Today, real estate taxes are based on the value of the structure and the land. If a new building goes up, taxes rise because of the higher value of the structure. However, since land values are the real driver of HABU, and the nature of the neighborhood determines HABU, a more efficient strategy is to tax the land values much higher than the structure value.

A land tax would affect the Development Gap calculus since those with large, underutilized lots would be paying a high tax but with little income to pay for it. They will, therefore, seek to build on the land to create more revenue to pay for the taxes. But land taxes only work if densification is allowed. You can’t turn up the heat by taxing land and then not allow new construction because of stringent zoning.

Furthermore, real estate taxes on the structures should focus on curbing the negative spillovers, or externalities, they create—that is, based on the harm they produce to society. For example, if a new building puts others in a shadow, then the owner should be pay a “shadow tax.” And to the extent that a denser structure will add burdens to the local infrastructure, the developer should pay a development impact fee.

Affordability is Political, Not Economic

At the end of the day, there is no such thing as a city running out of land. Land can be used intensely or sparsely used based on the demand for each location. The supply of lots determines land values across the city—the more supply, the lower the land values, all else equal. Today’s astronomical price of land is due to the fact that too many barriers exist to bring the land up for sale. As a result, current landowners enjoy a “scarcity premium.” When a valuable lot comes up, naturally, the HABU is a luxury condo. So, the high land values are not the cause of the housing affordability problem—they are a symptom that cities are not releasing enough land for needed housing.

What stops officials from allowing the densification is push-back by those who fear new development will harm them in some way. Thus, change requires carrots and sticks to bring people on board. Abundant housing policies would relieve pressure on land prices.

In the next blog post, I will discuss New York City in detail, investigating what is gumming up its ability to provide more parcels for new housing.

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^[1] Now, you might say that developers are strategic—only they know what something is worth because they spend years plotting (no pun intended) and scheming to change the zoning or slowly and quietly assembling small lots. This is true, but the land is not presented to them as a blank slate. The developer can see that certain frictions are holding up a more profitable use and work toward unleashing the value. This developer is engaging in a form of arbitrage, as it were. Additionally, since neighborhood diversity is a key desideratum, housing policies, discussed above, can work to maintain neighborhood diversity–but they can only do so within a context of abundant housing at all locations.

^[2] It’s important to recognize that Nimbyism is a form of Prisoner’s Dilemma. From the individual household perspective, to be a Nimbyist is perfectly reasonable and rational. Everyone naturally wants to protect what they have. However, from the point of view of society, preventing neighborhood densification is inefficient and leads to all sorts of social problems, including housing unaffordability, greater wealth inequality, more segregation, and lower economic growth.

^[3] For that matter, when the abatements are withdrawn, owners strategically hold onto their lots in anticipation of new abatement being offered. Subsequently selling them without the abatements likely means taking a loss on the investment. Thus, the expiration of the abatements means fewer lots will be offered up until new abatements are enacted.

November 27, 2023 by Jason Barr Leave a Comment

How Deadly Were Gotham’s Tenements? Infectious Disease in the 19th Century (Part II)

Troy Tassier and Jason M. Barr November 27, 2023

Prominent in the list of dangerous and aggressive nuisances are the tenement houses of the city….We thus speak of the inhabitants of the tenant-houses as constituting a class, and as being allied with the cause of sickness, pauperism, and crime. New York Times, June 12, 1865.

Throughout the 19^th century, New York City tenements garnered a reputation for vice, immorality, and, above all else, disease. As the above quote makes clear, most residents of tenement neighborhoods were lumped together and considered of equal nuisance. However, our previous blog post examined the risk of infectious disease mortality across Gotham’s wards during the height of tenement expansion from 1868-1910. We found something peculiar: some tenement neighborhoods had much lower infectious disease mortality rates than the citywide averages.

Density across Manhattan in 1895. Source NYPL Digital Collection.

In particular, the Lower East Side tenement wards were some of the safest in the city. On the other hand, more central and west-side tenement areas in lower Manhattan were among the most dangerous in terms of infectious disease mortality (see Figure 3 in Blog Post I). These differences beg the question: Why were some tenement areas relatively safe and others less so?

To begin the investigation, we plotted the rates of infectious disease mortality in the safe (Lower East Side) and less safe (risky) wards (Greenwich Village, Five Points, and the First and Fourth Wards) over time. The significant difference in risk began in the late 1880s. The decade from 1868-1878 saw minimal differences between these two regions. What was the same, and what was different about these wards? The short answer: it’s complicated!

Death Rates from Infectious Disease in Safer Tenement Wards vs. Riskier Wards. Note: The red line is the long-term city average (0.95%) from 1868-1910. Safe wards: 7, 10, 11, 13, 17. Risky wards: 1, 4, 6, 14. Source: here. For ward map see here.

Which of these things is not like the other?

Let’s review the possible hypotheses and see what the data suggest.

Tenement Concentration

At the beginning of our period, the 1870 census reveals that each group had about the same share of tenement homes, around 65 percent. Thus, each contained about 20 percent more tenements than the city-wide average. By 1900, New York’s explosive population growth led to a skyrocketing share of tenement dependence, with approximately 75 percent of all Manhattan residential units in tenements. (Data sources and analyses are here).

The safer wards closely matched this average, while the risky wards had a slightly higher share than the citywide average. Given that tenements were used citywide to house most residents, the presence of tenements in and of itself did not make one area riskier than another.

Density

Differing population density provides another possibility for the differences in mortality. Concentrating people increases the chances that an outbreak will spread quickly. However, density doesn’t fully explain the observed mortality difference. The safer wards were far denser than the risky wards. We can see the hyper-density of the Lower East Side (LES) tenements in the above map from the 1895 Tenement-House Committee.

In particular, the Tenth Ward had over 650 people per acre in 1900. All the wards in the safe grouping had at least 430 people per acre. On the other hand, the densest risky ward, the Fourteenth, had only 315 people per acre. All the other risky wards had under 235 people per acre. In short, the difference in mortality was not due to density.

Average Wealth

Wealth provides another potential reason for the difference in risk. Historically, more impoverished areas tended to be harmed the most during epidemic outbreaks. Other than the First Ward (which was wealthier per capita), the riskier wards had personal property per capita near the city median of $82 and real property per capita lower than or near the city median of $947 per capita. These wards were far from wealthy. However, the safer wards were even less affluent, on average. The LES Tenth, Eleventh, and Thirteenth Wards were the most impoverished of the city in terms of median wealth per capita—yet they had much lower infectious disease mortality.

Dampness and Poor Ecology

Could ecology and topography provide an answer? Damp areas and former marshes pre-European settlement might provide more fertile ground for disease than higher ground with better drainage, particularly for cholera and other waterborne diseases. We considered various possibilities, such as former marshlands, the presence of streams and other water sources, and the presence of Oak Tulip trees that grew on hillsides, where drainage was good. Again, none of these lead to a clear difference. In some areas, land conducive to the spread of infectious disease is associated with minimal mortality. Other sites that had a favorable environment had high rates of mortality.

In summary, most of the things that we associate as potential and obvious risk factors for infectious disease do not, in fact, correlate well with the different levels of infectious disease mortality. However, other differences stand out and begin to reveal the story of what was determining tenement health.

So, What’s the Answer?

To begin, we must step back and examine the bigger picture of change in the city. Manhattan’s population grew rapidly during this time. Between 1870 and 1910, the population increased by nearly 250 percent, from 942,000 to 2,330,000. Part of this increase occurred in the northern wards that were previously underdeveloped. The population of the Twelfth Ward (the northernmost and largest ward in terms of land area) grew by an astounding factor of 28. This was partly due to its minuscule population as of 1870 and its sheer size.

The city’s median ward saw its population increase by 26%. However, growth was very uneven across the island. Several southern wards, including three tenement wards in the risky group, saw population declines.

These three tenement wards stood in stark contrast to the safer tenement wards, each with a population that doubled (or more) between 1870 and 1910. This growth led to a sharp difference in density in this area compared to the other neighborhoods. This sharp rise in population and density would be expected to lead to more disease and not less. So, what happened? The explosive growth led to new construction in the area. These newly erected tenements met requirements that reformers put in place to keep the population safer from disease..

Enter Tenement Laws

As the population of Manhattan exploded, reformers worried about dangers of tenements. By all accounts, some dwellings were beyond horrible. The New York Times wrote of basements and backyards filled with sewage that drained into first-floor apartments. Interior rooms and entire apartments had no light or windows. Households with seven or more people lived in 6-foot by 7-foot rooms without space for everyone to sleep at once. Because of these poor living conditions, reformers called for action. As chronicled in the New York Times in 1865:

The fact is that the population of the city has become alarmingly great, and unless some attention is paid to its sanitary condition we shall be forced by the grim monster itself to bow down in dust and ashes of bereavement….

Is there a responsibility nowhere? Cannot something be done by the people, which will compel authorities to root out such abominations, remove such nuisances, and thus do much toward redeeming the children from lives of infamy, misery, and pollution?

In response, New York City passed a series of reforms to improve the safety of tenement buildings. The First Tenement Act of 1867 required a fire escape for each dwelling and a window for every room. The windows were intended to provide fresh air, ventilation, and light. However, many newly built apartments were compliant simply by installing a window to an interior hallway, which did little to improve ventilation.

Left: A Rooftop View of Two Dumbbell Tenement Shafts. Right: The Bottom of a Shaft. Sources: Left: Wikipedia. Right: Report of the Tenement House Department of the City of New York 1902/1903.

The Dumbbell

A series of additional acts improved conditions further and closed many loopholes. In 1879, windows were required to face a source of fresh air and light—not a hallway. Yet this, too, was met by developers with minimal compliance. Many newly built tenements simply added a narrow gap between buildings. This new building style became known as the dumbbell tenement after an 1879 competition meant to generate fresh ideas for tenement designs.

Developers typically erected this style of tenement stacked next to each other with only the narrow air shaft closed on each end, separating them as seen in the picture above. While this improved ventilation somewhat, later laws created more improvements. However, there was a problem with the dumbbell. Many buildings were not yet connected to sewers, and tenants could dump human waste and other garbage out of apartment windows into the narrow gap between buildings, creating new health problems. This was partly corrected in 1887 when each building was required to have an interior privy.

Two Tenement Plans. Left: A tenement that met the ventilation requirements of the pre-1901 laws. Right: A “new law” (1901) tenement plan that met the courtyard ventilation requirement. Source: Report of The Tenement House Department of the City of New York 1902/1903.

The New Law

Finally, in 1901, stricter and more comprehensive standards were established. New requirements ensured better lighting in hallways. Most importantly, indoor bathrooms were mandatory, and each tenement needed a large courtyard. The last requirement ensured ventilation because each room now had a window that opened onto the courtyard, a street, or the backyard. Most of these “new law” tenements were built in areas with the largest growth. These were the areas with the lowest infectious disease mortality in the city.

Safety with Growth

Data on new buildings and compliance with tenement laws is less available than data on infectious diseases. However, from the available data, the safer wards, which had higher rates of growth, were constructing more new tenements as the laws evolved to ensure more safety. This is also the time during which we observe the difference in infectious disease mortality in the two ward groupings.

For example, from an 1891 New York City Department of Health report, we found that the safe wards had 144 instances where building plans were filed for plumbing and drainage that year. The risky wards only had 16. A similar report in 1891 documents filings concerning light and ventilation. There were 152 filings for new building plans in the safe wards and 25 in the risky wards. From these data, it appears that by the 1890s, more new tenements were being constructed in the safer wards. This period falls shortly after the second generation of tenement laws were enacted.

We also can get a sense of the rate of new construction by looking at the total number of existing tenements in each ward in years where this data is available. In 1896, the safer wards contained 193 more tenements than in 1892. The number of tenements in the riskier wards increased by only 67 in these four years. Though we can’t directly ascertain building ages or compliance with the laws, certainly some buildings were torn down and replaced with improved and safer structures. The data gives us a sense that the safer group of wards had newer building stock that met the safer building codes of various tenement acts. Compliance with these more recent reforms likely made the Lower East Side Wards safer.

Additional evidence comes from reports of new tenement construction in tenement districts after 1901. The report’s maps show that far more new tenements were built in the safer wards.

New law Tenements Erected between January 1902 and July 1903. Dots represent 1902 construction and triangles represent 1903 construction. The majority of new tenements during this time period were built in the safer wards. Source: Report of The Tenement House Department of the City of New York 1902/1903.

Rear Tenements

The 1900 tenement house census gives us another glimpse of the age and quality of the building stock by counting the number of rear tenements in each ward. Rear tenements were additions located in the back alleys of tenement neighborhoods. Many were ramshackle dwellings that were even more spartan than the typical tenement buildings you see in movies or on a tour at the New York City Tenement Museum.

In most cases, rear tenements were the lowest form of shelter in the city. Sometimes, they were built purposely as residences. Other times, they were converted sheds or sometimes even old outhouses. Generally speaking, they were not the four- or five-story stone and brick structures that most envision when considering New York City tenement houses. The number of rear tenements in the risky Fourth and Sixth Wards was far higher than in any other ward of the city—nearly one in four. Again, this leads one to believe that the building stock in the risky wards was older than in the safer wards.

From whence They Came

The final significant distinction between these two groups of tenement wards concerns the place of origin of the respective tenement populations. As of 1900, each risky ward contained between 61% (1^st Ward) and 78% (4^th Ward) Irish or Italian immigrants. The Irish fleeing famine in the mid-19th century likely had little of monetary value upon arrival. While many immigrants from other locations certainly lacked wealth, they presumably were not as destitute on arrival as the Irish famine refugees.

On the other hand, the safer ward groupings contained populations overwhelmingly from Eastern Europe. Each of these wards had at least 75% of its population originating from Russia, Poland, Germany, or the Austro-Hungarian Empire. Many immigrants were Jews escaping discrimination and persecution. While they may not have been wealthy upon arrival, many were likely not as poor as those who settled in places like Five Points.

Two Photos of Rear Tenements in late 19^th Century Manhattan. Note the traditional tenement buildings sit in the background of each photo. Source: Jacob Riis’s 1890 book, *How the Other Half Lives: Studies among the Tenements of New York.* Images from here.

Reform for the Win

Putting all of these factors together, a picture begins to emerge. The riskier wards likely had older, less sanitary, and less safe dwellings concerning infectious disease risk. Because of their earlier reputation as bastions of infectious disease, they were likely avoided by all with the financial means to do so.

At the same time, other Irish and Italian neighborhoods emerged farther north in the city. The Fifteenth Ward, discussed in the previous post, contained just over 50 percent of residents with Irish or Italian heritage. So did the 21^st Ward just to the south of present-day Grand Central Terminal. Other areas throughout the city had significant Irish and Italian immigrant populations where people with relatively higher incomes could settle. The fact that some people remained in the most disease-ridden area of the city in older, decrepit housing likely indicates that these people didn’t have the financial means to escape to anywhere better.

On the other hand, the safer Lower East Side tenements likely contained newer buildings that were more sanitary and included more ventilation and light. It wasn’t that these areas were wealthy–far from it–but the living conditions and newer building stock likely allowed the people who settled there to avoid at least some risk from infectious disease mortality.^[1]

Reevaluating Death and Disease in the Tenements

While New York City’s 19^th-century tenement neighborhoods received a bad reputation for high infectious disease rates, there is far more nuance than the folklore suggests. Disease was part and parcel citywide in the 19^th and early 20^th centuries. No area, rich or poor, tenement or not, was spared from infectious disease risk. Yes, some tenement areas were particularly dangerous, but not all. Likely, the evolving tenement reforms of the late 19^th and early 20^th centuries created safer conditions in the tenement districts that saw the most population growth and new construction of safer buildings.

You can read Part I of the blog post series here.

Troy Tassier is a professor of economics at Fordham University. He is the author of the forthcoming book, The Rich Flee and the Poor Take the Bus: How Our Unequal Society Fails Us During Outbreaks. He also writes the At the Margin Substack newsletter.

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^[1] One can also understand how these wards might have earned an undeserved reputation simply because of their density. With so many people living in these areas, even an average level of infectious disease would stand out in absolute numbers. If two wards each had one percent of their population die during an infectious disease outbreak but one of the wards contained five times the density compared to the other, the denser ward would have five times the number of deaths. Thus, if newspapers and other sources of information simply report stories about the number of casualties, the denser areas will garner a more dangerous reputation that they don’t deserve simply because of the sheer number of deaths.

November 6, 2023 by Jason Barr Leave a Comment

How Deadly Were Gotham’s Tenements? Infectious Disease in the 19th Century (Part I)

Troy Tassier and Jason M. Barr November 6, 2023

Those sickened must be cured or die off, & being cheifly [sic] of the very scum of the city, the quicker [their] despatch [sic] the sooner the malady will cease.

John Pintard, a founder of the New York Historical Society and a former secretary of the New York Chamber of Commerce wrote these words to his daughter on July 13, 1832. New York City’s first great cholera epidemic had begun just two weeks earlier. The outbreak continued through September and 3,500 cholera deaths were officially recorded within the city. In just three months, 1.5 percent of New York City’s population died from the disease.

Pintard’s crass words matched the feelings of many 19th-century upper-class New Yorkers. For Pintard and others like him, illness from infection, particularly cholera, was a sign of moral turpitude. Those with an upright character were protected from ghastly contagions. In another letter to his daughter, Pintard stated these feelings explicitly: “At present [cholera] is almost exclusively confined to the lower classes of intemperate dissolute & filthy people huddled together like swine in their polluted habitations.”

Location of Officially Recorded Cholera Deaths in 1832. Source: Pulitzer Center.

In part, people of Pintard’s ilk were correct in their belief of the concentration of cholera. The Sixth Ward, the location of the infamous Five Points neighborhood, contained the most severe concentration of cases and deaths as the following map of 1832 cholera deaths reveals. The large red blotch in the middle is in Five Points. Although not known at the time, cholera was a waterborne disease and spread more easily in Five Points because the neighborhood was constructed over the filled-in Collect Pond, creating poor drainage before New York fully built out its water and sewer system. That the poor immigrants were “forced” to live over former swamps and lakes was, certainly, due little to their supposed immorality or “dissolution.” It was simple finance–those in Five Points couldn’t afford to live elsewhere.

The Safety Dance

As a prophylactic, many wealthy, on the other hand, simply fled to safer and more spacious environments. As historian Charles Rosenberg writes,

A hyperbolic and sarcastic observer remarked . . . ‘fifty thousand stout-hearted. . . New Yorkers scampered away in steamboats, stages, carts, and wheel barrows.’ Farmhouses and country homes within a thirty-mile radius of the city were filled. Yet the exodus continued . . ..

However, only the wealthy could afford to escape. Rosenberg further laments, “The poor having no choice, remained.”

The 1832 cholera epidemic wasn’t the first or the last outbreak to roil New York society. Smallpox and yellow fever were persistent concerns throughout the early decades of New York’s growth. Cholera, measles, tuberculosis, typhus, typhoid fever, and other infectious diseases would continue to devastate families throughout the 19^th century.

Poverty as Vice

In the popular consciousness, Manhattan’s Lower East Side tenements became synonymous with filth, poverty, density, and disease. In 1842, Charles Dickens described one dilapidated tenement in his American Notes for General Circulation:

What place is this, to which the squalid street conducts us? A kind of square of leprous houses, some of which are attainable only by crazy wooden stairs without. What lies beyond this tottering flight of steps . . . A miserable room lighted by one dim candle and destitute of all comfort, save that which may be hidden in a wretched bed. Beside it sits a man: his elbows on his knees: his forehead hidden in his hands. ‘What ails that man?’ . . . ‘Fever’ he sullenly replies without looking up.

Jacob Riis provided the most famous descriptions of life in the tenements in his 1890 classic, How the Other Half Lives: Studies among the Tenements of New York. Like Dickens, poverty, density, disrepair, and disease are inexorably intertwined in many of his descriptions. He describes one tenement apartment,

The family’s condition was most deplorable. The man, his wife, and three small children shivering in one room through the roof of which the pitiless winds of winter whistled. The room was almost barren of furniture; the parents slept on the floor, the children in boxes, and the baby was swung in an old shawl attached to the rafters by cords . . . The father, a seaman, had been obliged to give up that calling because he was in consumption, and was unable to provide either bread or fire for his little ones.

“Consumption,” at the time, was the term for tuberculosis.

Blaming the poor, for citywide epidemics, Riis wrote, “In the tenements all the influences make for evil; because they are the hot-beds of the epidemics that carry death to the rich and poor alike.”

Density and Disease: A Deeper Analysis

These quotes and others like them, give a sense that some lower class neighborhoods were continually beset with disease, while the ones housing the prudent and “upright” upper class were disease-free. Yet, the 1832 cholera map displayed above shows that there was clearly disease and suffering throughout the city. So, we thus need to return to the question, were the tenements really that much worse than other districts in terms of infectious disease mortality? Are the conclusions of the rich and the reformers as grim and conclusive as they suggested?

To investigate this question, we compiled data from the National Bureau of Economic Research (NBER), Historical Urban Ecological data set. The data set contains information on a variety of 19^th– and early 20th-century demographic and health-related data, including deaths from various infectious diseases from 1868 through 1927. The data set does not include all years—in particular data from the 1918-1919 influenza pandemic is missing, as well as infectious disease data for the years 1880-1888—but it does allow for us to study broader trends across time and space.

We focus our analysis during the height of tenement growth from 1868-1910. The data is organized at the level of New York City wards, which were neighborhood demarcations used for elections of various municipal offices, such as aldermen (analogous to today’s city council members). Across Manhattan, there were 22 wards. While they are numbered in a somewhat haphazard fashion (shown on a map below), in general, the lower-numbered wards were closer to the southern tip of the island.

Death Rates

During this period, the data reveal that, on average, about 0.95% of New Yorkers died per year from infectious diseases. Although rates of death certainly varied by age (with the youngest children particularly susceptible), we can think of this as a baseline risk that each person living in the city faced. In other words, unadjusted for age, location, or time period, an individual had just under a 1 in 100 chance of dying from an infectious disease each year. However, from the historical descriptions, we would expect that certain areas had higher risk than others.

To identify these differences, we run statistical tests (regressions) aimed at identifying the New York City wards with the most risk while controlling for yearly trends (mortality was falling over the second half of the 19^th century). (Data sources and results are given here.) The map below shows each ward’s death rate relative to—that is, above or below—the citywide average. The results suggest that the reformers and the wealthy scoffers did not quite have their stories right.

Blue indicates the ward had, on average, a lower death rate than the city average. Red indicates above the city average. White is about the same as the city average. Death Rate = total deaths from infectious disease / population. Source: here.

Across Wards

To focus on the heart of the matter, we have created a “matrix” of topologies by dividing the wards into those that contained relatively high or low density, respectively, and those that were “safe”/low-risk or “unsafe”/high-risk based on their death rates compared to the city average.

Low Density-High Risk: The First Ward

The First Ward sits at the southern tip of Manhattan. While it didn’t have the notoriety of the tenement wards for infectious disease it had the highest rate of infectious disease deaths anywhere in the city over our time of study. In the late 19^th century, before the opening of Ellis Island in 1892, this ward was the literal gateway for the majority of immigrants entering the United States through New York City. It is estimated that eight to twelve million immigrants passed through the Emigrant Landing Depot, known as Castle Garden, during its time of operation from 1855 to 1892.^[1]

Many of the immigrants arrived nearly penniless, and given their lack of funds they could not venture far from the landing when they first entered America. Often, they settled briefly in almshouses and boarding houses nearby as they searched for employment and more permanent housing. Unfortunately for these immigrants, our analysis suggests that the First Ward was the easiest place for contagions to multiply. Here deaths from infectious disease were 52% greater than the citywide average.

Although the First Ward receives far less attention than the Lower East Side tenements, elevated disease risk should not be surprising. During this time, the experience of most immigrants was tortuous. They were stuffed in the cavernous underbelly of a ship without ventilation and, in some instances, even light. It was not uncommon for some of these steerage passengers to die from disease or starvation en route to America. Although many were inspected for disease upon arrival, some infected passengers certainly passed through the port and into the First Ward undetected. Various diseases were thus let loose to fester in the First Ward where many immigrants made their first night’s sleep.

A photograph of New York Harbor, Governor’s Island, Staten Island, and Castle Garden Aquarium, 1894. J.S. Johnston photograph collection, 1890-1899. Source: nyhistory.org.

Low Density–Low Risk

In contrast to the First Ward, the adjacent Second Ward was one of the safest in the city. It sits between the southern port and the notorious tenement districts. John Pintard, whose quote began this post, was elected an Assistant Alderman of the East Ward (which became the Second Ward at a later date). This area was the original seat of affluence in Manhattan and home to many who made their fortunes as Manhattan’s first merchants and bankers.

However, after the Civil War, this district was given over nearly entirely to industry and commerce and had few residents of any stripe. Similarly, the Fifteenth and Sixteenth Wards also contained far lower infectious disease mortality. Each of the Second, Fifteenth, and Sixteenth Wards had infectious disease mortality 16% lower than the citywide average.

Late in the 19^th century, the northern wards of the city were at the heart of a great migration. As the lower wards became overcrowded, transportation options (such as the horse-drawn streetcars and later the elevated railways and the subway) allowed for faster and easier commutes from homes to places of work. Much of New York’s middle-class population moved north. As they did so they skipped over the dense tenement and manufacturing districts that populated Lower Manhattan above the Second and Third Wards.

Many of the affluent landed in places like the 15^th and 16^th Wards, along Broadway, Fifth Avenue, and around such parks as Washington Square and Madison Square. Throughout this period the northern wards had relatively low density and infectious disease mortality was near average or slightly below. Even the 22^nd Ward, home to Hell’s Kitchen, with shanty towns along the Hudson River docks, had infectious disease risk lower than the city average.

The High-Density Neighborhoods

Focusing now on the high-density neighborhoods, we see something that is not, in fact, obvious. Some of the densest wards had infectious disease death rates that were far lower than the city average. In fact, some of the most-dense tenement districts had the lowest infectious disease mortality in the entire city. This certainly suggests that density, in and of itself, was not the great evil that reformers portrayed it to be, at least in terms of infectious disease risk.

In particular, the tenement neighborhoods of the Lower East Side had two clusters—a higher-risk zone and a lower-risk one. The higher-risk zone was located in the central wards of Lower Manhattan that included Five Points, Little Italy, and Greenwich Village. The lower-risk zone, on the other hand, was located on the east side, and included dense Jewish and German neighborhoods. In fact, in 1900, the Tenth Ward, home to many Jewish immigrants, was arguably the densest neighborhood on the planet, with some blocks having densities as high as 1,000 people per acre. Yet, the Tenth Ward had infectious disease mortality 19% lower than the city average.

The Infection Puzzle

This variance in rates of infectious disease mortality across the tenement districts offers up a puzzle. Density and poverty were not uniform predictors of disease mortality. What was going on? Why did the reformers seem to overgeneralize and misunderstand what was happening in the 19^th century? We will provide the answers in Part II of this blog post, coming soon.

Continue reading Part II of the post here.

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^[1]Unfortunately, a fire at Ellis Island destroyed most of the Castle Garden immigration records in 1897 so precise counts and much history of entry through Castle Garden are lost.