Issue 2: Planning
Hanging on for Dear Life
March 23, 2025
On July 1, 1846, a 28-year-old Hungarian physician named Ignaz Semmelweis was appointed assistant to the director of one of the obstetrical clinics at Vienna General Hospital. He eagerly accepted the role, which included overseeing clinical operations and recording statistics about patient outcomes.
Soon, Semmelweis was struck by a clear pattern in the mortality rates among women who had just given birth, which were significantly higher in the area of the hospital staffed by doctors and medical students (where nearly one in 10 mothers died) than in the area staffed by midwives (where around one in 25 mothers died).
Semmelweis hypothesized that the difference was due to cross-contamination that took place when doctors and medical students performed autopsies and subsequently delivered babies without washing their hands in between. In 1847, he instituted a strict policy of handwashing with chlorinated lime water for everyone who worked in the maternity ward. The mortality rate in the doctors and medical students’ clinic dropped to 5% for the remainder of 1847 and fell to 1% in 1848.
Despite the clear evidence that handwashing is beneficial, Semmelweis faced significant professional backlash for implementing this new practice. Many of his colleagues were skeptical of his observations. Some were outraged by the suggestion that they might be culpable in the deaths of their patients. Still others found it suspicious that Semmelweis couldn’t provide a theoretical basis for his findings; there was, at the time, no scientific explanation for why handwashing would be so effective in reducing mortality. The prevailing theory of disease was that “vapours,” or unclean air, caused illness. In a small step toward developing a more modern account of disease, Semmelweis hypothesized that, instead, “cadaverous particles” were being transmitted on the hands of clinicians.
After writing furious open letters attacking doctors who ignored his findings, Semmelweis was dismissed from his position at Vienna General Hospital. Even after, he faced continued criticism from the medical community. He was ridiculed, ostracized, and eventually committed to a mental institution by his peers, in 1865. He died after just 14 days in the asylum.
It was only several years after his death that Semmelweis’s ideas gained traction in the medical profession. Louis Pasteur introduced his germ theory of disease, which provided a scientific explanation for Semmelweis’s observations, in the late 1850s; over the next few decades, it became widely accepted.
Today, Semmelweis’s emphasis on data, experimentation, and methodically testing different hypotheses would be called scientific, or perhaps evidence-based medicine. But, in his time, it was considered outrageous. Nothing about Semmelweis’s findings changed in the years following his death. What changed was the willingness of his peers and contemporaries to absorb new information and integrate it into their view of the world.
The type of resistance Semmelweis encountered is not confined to medicine. Semmelweis’s story is a parable for practitioners in just about any profession — including those that create our cities: urban planners, architects, and engineers, both within the civil service and in private practice. Let’s call this group of professionals “city-builders.”
Like any other group of experts with established conventions and prevailing norms and beliefs, we city-builders often make the very same types of intellectual errors that Semmelweis’s peers made in the 19th century.
Professions of all types tend to be dominated, almost by definition, by people with the most accumulated experience in a field. Psychologically, people become increasingly attached to (and confident in) beliefs when they are based in actions they have repeated over and over. In other words, the most experienced professionals have a compelling reason to hold on very strongly to whatever beliefs they have about their discipline. These are people whose identities and professional longevity have depended on a particular worldview and way of doing things. Because of that very longevity, they get to define the paradigm, or prevailing conceptual framework, of their time.
Updating one person’s beliefs is hard. Shifting the paradigm of an entire discipline is much harder. The senior obstetricians who most aggressively disagreed with Semmelweis had been providing medical care with poor hygiene for their entire careers. Acknowledging the importance of hygiene would mean acknowledging a career of actively (if unknowingly) harming patients. It would have meant admitting — including to themselves — their own ignorance and the harm they had caused. This psychological task was necessary for the advancement of the profession but extraordinarily painful for the seasoned practitioners who were confronted with it.
All disciplines face this dynamic from time to time: an inherent push and pull between conservatism and openness, stability and change, knowledge and experimentation.
City-builders are no exception. North American urban planners, lenders, and real estate professionals, famously, were staunch defenders of redlining, racial segregation, and urban renewal at various times, and not that long ago. They didn’t defend these policies out of pure malice — they were widely thought to be good planning practices. But it led to the displacement and systemic, generational disadvantage of millions of people. Despite decades of heated political controversy, the well-documented brutality of government segregation, and the rise of the Civil Rights movement, it wasn’t the planning profession that put an end to these kinds of exclusionary practices. It was the supreme courts of the US and Canada. Planners and other city-builders fell in line only after the laws were changed.
This seems like a good moment to ask ourselves:
What, exactly, are the mistakes that we as city-builders are making today?
Architects often focus on cutting-edge technologies or obscure, experimental forms of design, rather than advocating for proven methods of dense urban design that are more sustainable, affordable, and resilient than the status quo produces. For example, if you attend design conferences or read publications on sustainable design, you will hear much more about robotic modular construction, heavy timber structures, and state-of-the-art glazing systems (which still perform dismally compared to even a code-minimum insulated wall) than you will about the kind of dense development that makes New York City the lowest-carbon-emitting metropolis in North America. Rarely do city-builders ask how we can become more like New York, where most of the buildings were built with old tech.
Engineers, who we often consider to be the most technical and neutral of city-building professionals, are not immune to this type of resistance. For example, transportation engineers continue to design roads that privilege high vehicle speeds, creating extremely dangerous circumstances for pedestrians, even while other, demonstrably safer, designs are developed around the world. Engineers who call for new, better standards can be punished severely. The case of Charles Marohn, a former engineer who founded Strong Towns — a non-profit that advocates for new patterns of financially sustainable urban development and pedestrian-friendly transportation planning — is one such example. After years of arguing against orthodoxies in transportation planning, ones that led to car-centric street designs that put pedestrian lives at risk, he had professional censure proceedings started against him by members of his state licensing board. (Strong Towns has posted the details of this litigation on its website.)
Planners frequently remain stuck in outdated paradigms in a very direct way: they are often employed by governments to maintain and reinforce existing rules. Many spend their careers generating guidelines, standards, and professional best practices; these necessarily uphold the conventional wisdom of the day. The planning profession tends to treat these like Semmelweis’s peers treated their model of disease: as unassailable truths, rather than frameworks that should be tested against reality.
For example, in my city of Toronto, developers had spent decades asking planners to reduce parking counts in new buildings; they found that garages often went partially empty because parking requirements far exceeded market demand in many neighbourhoods. But that evidence didn’t matter because “good planning” was defined by a theoretical model of how people get around in a city — with cars. And municipal planners were charged with upholding these good planning principles.
Urbanists like Donald Shoup had been providing detailed economic and conceptual arguments for fewer parking spaces for decades, but the message didn’t seem to get much traction until 2020 or so, when a confluence of factors — media coverage, academic research, the rise of YIMBY urbanism, and professionals updating their individual beliefs — eventually changed public policy.
On December 15, 2021, Toronto enacted its own paradigm shift, rolling back nearly all of its minimum parking requirements. In fact, it switched its approach to parking planning entirely and began placing parking maximums on new projects. Overnight, the undergirding planning model changed. Since then, I have already seen planners request fewer parking spaces than proposed, even when that proposed number is below the maximum allowed by the new rules. This would have been absolutely unthinkable two years ago.
There are many such cases: top-down theories currently control numerous aspects of building design, ranging from the critical to the mundane. Buildings are currently approved or rejected based on orthodoxies around unit mix, amenity design, signage, the use of outdoor space, and even material colours.
We all want to improve the quality of our urban places and set our cities up for success. By letting go our own professional orthodoxies, we may find it easier to do just that.
Which brings me to perhaps the most stubbornly held outdated belief city-builders have.
Regardless of industry, demographic characteristics, or political beliefs, people today tend to agree on one thing: we face a housing-affordability crisis. And, among our city-building professions there is, still, an ongoing debate about whether this is in large part due to a lack of housing supply.
The data appear to be in. The heavy balance of academic research, which happens to align with basic economic theory, common sense, and real-world experience, suggests that the single biggest driver of high housing prices is a lack of supply. There have been two excellent literature reviews in the last five years that paint the picture clearly.
The first of these, “Supply Skepticism: Housing Supply and Affordability,” was published by the NYU Furman Center in 2018. This paper reviews decades of research on the interaction between supply and affordability and finds unequivocal evidence that supply (specifically supply elasticity, or the ability for supply to change in reaction to demand) is a necessary condition for affordability, in aggregate. An update, which clarifies and reinforces these findings using new research from the last few years, was published in August 2023.
The second, “The Effect of Market-Rate Development on Neighbourhood Rents,” published by the UCLA Lewis Center for Regional Policy Studies in 2021, uses more recent, detailed data to clearly demonstrate that this effect plays out not just in the aggregate economy but also at the local level. New market-rate rental housing reduces displacement and slows the rate of market-rent increases in the nearby area, the researchers show. In fact, they find that the price-reducing impact of more supply more than offsets any increased demand (from, say, new neighbourhood amenities) at any distance.
There are countless other high-quality studies that provide compelling, detailed evidence. For example, Finland collects population data for every citizen in the country and allowed researchers to study the addresses of individuals over time. The researchers found that for “for each 100 new, centrally located market-rate units, roughly 60 units are created in the bottom half of neighborhood income distribution through vacancies.…Even more remarkable, 29 vacancies are created in neighborhoods in the bottom quintile of the income distribution.”
And yet, despite this accumulated evidence, a great many planning professionals, architects, academics, civil servants, and politicians will ridicule the suggestion that we need to increase supply and are actively hostile to those who suggest it, even within their own disciplines. Many professionals have a deeply ingrained belief that only non-market regulatory measures, such as rent control and inclusionary zoning, or demand-side measures, like immigration controls, monetary policy, and prohibitions on short-term rentals, can address housing affordability. Even more are skeptical that scarcity might be a contributing factor, much less a root cause, of our affordability challenges.
Ultimately, I see these views as easily reconciled. The supply skeptics often claim that more supply alone will never solve affordability: markets simply don’t work that way, and there is no incentive for the private sector to house people at the bottom of the income distribution.
I agree.
Semmelweis never would have claimed that handwashing would solve 100% of mortality in his clinic. But he did discover what appeared to be the single largest cause of death: poor hygiene. Similarly, those who advocate for more housing supply rarely, if ever, claim that supply and supply alone will solve the affordability crisis. But it’s clear that abundant supply makes the problem of unaffordable housing more manageable. It clearly reduces the number of people who need help getting housing. Like the medical professionals who hesitated to acknowledge culpability for not washing their hands, our city-building professionals are slow to recognize their own role in preventing access to a most basic human need: shelter.
City-builders should be focusing all our time and energy on creating an affordable housing market with a variety of high-quality structures that people want to live in— a market that would be dynamic and flexible enough to quickly respond when the needs of households shift.
But, partly because we are attached to outdated views about the economics of housing, we have delivered precisely the opposite: a shortage in the supply of affordable housing options, ever-lengthening review processes, bureaucratized design decisions, higher taxes and fees on development, and construction-throttling price controls.
In 2020, according to the OECD, Canada ranked 34th out of 35 high-income countries for the time required to obtain a building permit — only Slovakia was slower. It takes Canadian builders 168 days longer, on average, to receive a permit than they would in the US — and that doesn’t include the years-long planning process that’s required before a permit application can be submitted. According to Scotiabank, Canada has the lowest per capita stock of housing units (of any kind) among G7 countries.
In Canada, we also burden new housing development with extraordinarily high government costs. If a project in Toronto is approved today, fully 20–30% of its entire project budget will be paid directly to government in the form of taxes, fees, and surcharges. This figure does not count any of the costs required to adhere to various planning and regulatory requirements, such as legal fees or reports from specialist consultants, nor does it count the cost of delays that inevitably result. In the US, government charges typically come to less than 10% of total project costs.
The cost of housing has risen beyond reach for the large majority of Canadians, who now rely on massive levels of debt and/or family assistance when finding a place to call home. According to RBC, the average chunk of household income eaten up by homeownership costs climbed from 41% in 2016 to 63% in 2022. It now takes the average buyer 17 years to save for a down payment in Canada — 27 years if you live in Toronto. The picture isn’t much better for rental housing. Vacancy is at a 20-year low and rents are up 13% since 2015 nationwide and getting worse.
It’s time to let go of things that don’t work and try something new — to shift the paradigm.
First, we city-builders should acknowledge that more supply on its own will never address all of society’s housing needs. We have not eliminated hunger, even as food prices have fallen drastically over the last century. And we will not eliminate homelessness and financial precarity by building more homes. At the same time, we must also acknowledge that most of our housing challenges — high prices, real estate speculation, low-quality housing, huge waitlists for subsidized housing — are symptoms of scarcity, not symptoms of abundance. Producing more food is a precondition for solving hunger; producing more homes is a precondition for solving a housing crisis.
We must acknowledge the importance of housing supply in addressing housing affordability, though it runs counter to many years of experience and habit, and we must advocate for privileging production over other valid but less important considerations, which often slow or prevent growth. It’s legitimate to consider shadow impact, noise, infrastructure capacity, and neighbour feedback when reviewing proposed housing projects, but the bar for rejecting or reducing proposed housing supply should be very high. Our city-building professionals should start from a position that housing must be built somewhere and a big part of their job is to figure out where and how, as expeditiously as possible.
Planners should embrace evidence-based policy-making and work to remove regulatory barriers that constrain productive growth. This means addressing restrictive zoning, reducing the cost and time of development approvals, and increasing the availability of public land for housing development. New sewers can be built, as they are every single day in other cities. New transit can be incrementally added over time. New trees can be planted. But every home left unbuilt because of professional interference is a household that has been denied the opportunity to live in a place they want to live. This is the redlining of our era.
Architects and engineers should leave the sidelines and take a central position in our debate about growth and prosperity. Too often, my peers complain privately about the difficulty of building and about the ruinous nature of many technical rules. But they demur in public, leaving advocacy to policy-makers and industry groups. They are the holders of technical knowledge and must speak up when policy runs against the public interest.
My hope is that our city-building professions will start to recognize when they are behaving like Semmelweis’s detractors — adhering to tired orthodoxy that no longer fits with reality and punishing their peers who dare to say otherwise. Supply-skeptical true believers must be publicly challenged and presented with the evidence against the status quo. And those city-builders who know better should use the housing crisis as an opportunity to reassert their profession in the public sphere, rather than take a back seat to politicians, developers, and public officials.
The stakes are too high and the cost of failure is too great. UP
Brendan Whitsitt is the founder of Imprint Development, a rental-housing company located in Toronto. When he’s not building housing, he’s thinking and writing about housing.
