Say you want to ensure average rents for two bedroom apartments are affordable, at about $1,200/mo (again, around the rent level of Edmonton, vacancy rate around 5%). The takeaway from the above would appear to be that if you want to lower rents to this level in a market like Metro Vancouver (average rent @ $1,650, asking rents much higher, vacancy rate around 1%), then you need to ensure that a lot more two bedroom apartments come on the market to rent. In short, you don’t have enough housing.

Exactly how many two bedroom apartments would you need to add to bring average two bedroom rents down to $1,200/mo in Vancouver? This is a tricky (and worthy) question to answer. It would require knowing the shape of the demand curve (made up by knowing how many apartments would be rented at each rent from, say $1/mo to $1 million/mo). It would be difficult to figure this out, even if we could ask everyone in Vancouver what rent they’d be willing to pay for a two bedroom apartment. Why? Two reasons: 1) at lower rent points, some people might be willing to pay for multiple two bedroom apartments (rich people do all kinds of odd things, and when we use price as our metric, the whims of the wealthy matter more than the needs of the poor); 2) we should almost certainly assume that there are a lot of people living outside of Vancouver (including former residents) who would love to move here if they could find a two bedroom apartment for $1,200/mo. They only get a vote in how much housing gets built through their influence on the demand curve. Otherwise they don’t get heard at all. So it’s difficult to tell just how many two bedroom apartments we would need to add to bring Metro Vancouver rents down to $1,200/mo.

Another way to set a metric is to set an ideal vacancy rate instead of a specific rent. Vacancy rate targeting was explicitly mentioned by several candidates in the last City of Vancouver civic election. Inflation-adjusted rents tend to fall when vacancy rates rise above 3%. Setting a vacancy rate target of 4% or 5% will work to deflate rents.

In general, if your goal in asking if a place has enough housing is to preserve the affordability of market housing, then prices (or rental vacancy rates) should be your metric. If prices are higher (or lower) then you want them to be, then you should work to add to (or reduce) the supply of housing accordingly.

But how do we add to the supply of housing? Generally the most important way to add supply is to build more housing. It’s what builders do. But it’s worth noting that if they want to build more housing, builders get stuck in the middle of even more demand and supply curves. Labour, materials, and (most variably) land all influence the costs of constructing new housing. Just like buyers and sellers in the housing market, builders also watch price signals, and they tend to build when they think they can sell the housing they construct for a significantly higher price than they pay to purchase labour, materials, and land, with the difference equal to profit. The Minimum Profitable Production Cost (MPPC), or the minimum cost to bring a new unit to market, sets a hard cap on when builders have any incentive at all to try and add housing. As a result, it also provides a lower bound on the price of new market housing. And this minimum cost rises as density increases and construction becomes more involved and expensive (the minimum profitable production cost of new rental housing in Vancouver is currently too high for market developers to offer new two bedroom apartments at $1,200 market rents). Not surprisingly, holding other characteristics constant, new housing always tends to be more expensive than old housing. As a result, when you compare new housing to old housing, it might seem like new housing is doing nothing at all to bring down prices. But when you consider that building new housing is the primary way of adding more dwellings to the market overall then you get how new housing might “soak up” some of the demand in a given market, thereby lowering the prices of older housing from where they’d otherwise be and bringing down prices overall. Of course, building new housing only adds to the total housing market to the extent that you build more new housing than you demolish, a point to which we’ll return below.

Aside from demolitions, how would one reduce the supply of housing? Generally speaking, we seldom see demolitions exceed new construction, so this doesn’t happen much. But there are a few examples we can talk through, perhaps most prominently AirBnB. In response to new profit-making incentives of AirBnB, many property owners have removed dwellings from the long-term rental market into the short-term, hotel-style market (these markets once weren’t so distinct, but they have become so over time with the passage of laws like BC’s Residential Tenancy Act). As dwellings get removed from the long-term rental market, it drives down vacancy rates and correspondingly drives up asking rents for those units remaining.

What else matters? Location, location, location. Additions and subtractions from the supply of dwellings for sale or rent don’t just have local effects. Their effects spill over into places near and far, tied together by their fixture to land and to transportation networks. For instance, the effects of building and renting out a bunch of new housing in Downtown Vancouver may be felt in asking rents in suburban Surrey. The degree to which additions of housing in one place affect rents in another is heavily dependent upon how long it takes and how much it costs to travel between them as well as to job centres and amenities. That said, some observers suggest that hyper-local “induced demand” may come in to play, meaning that new construction in Downtown Vancouver could potentially drop asking rents in suburban Surrey more than asking rents Downtown. The evidence gathered to date suggests this likely doesn’t happen much, but certainly the scale of the metric matters when thinking about how the addition of new supply affects prices and rents.

So far we’re also talking strictly about dwelling characteristics like bedrooms and size, but not about the structural type of dwellings. We can’t add more single family homes in the inner municipalities in Vancouver, so market mechanisms are constrained in terms of reducing the rent or price when we restrict ourselves to single family homes in the inner municipalities. Being very picky on location can have similar effects. Adding condos or rental properties in the downtown peninsula is more expensive than adding them in e.g. Dunbar. Adding housing in downtown requires concrete high-rise, which is substantially more expensive than 4 or 6 storey low rise which can still add significant housing in Dunbar. Providing amenities like public spaces and libraries for a growing population is also more expensive in areas that are already denser. Given demand and various constraints, it’s quite possible that the market won’t ever be able to supply rental housing at a cost that can push rents down into the $1,200/month range (or push the sale price into the $250,000 range) for a 2 bedroom apartment in Downtown Vancouver. But Surrey seems possible. Regardless, if we want to try we have clear price signals that we’d need to add a lot more 2 bedroom apartments than we have now.

Considered as a class, metrics for Money per Dwelling, including prices (per dwelling, per sq ft, etc.), rents (per BR, etc.), rental vacancy rates, and sales listings, represent transactional data reflecting market pricing mechanisms. Inequality is built into these measures as a reflection of how market allocation weighs the whims of the wealthy of greater importance than the desperate desires of the poor. Correspondingly, reductions in inequality make for more egalitarian housing outcomes. Given market allocation of housing, this is the class of metrics people should turn to if they’re interested in achieving or preserving affordability. They provide the clearest path for identifying if there’s enough (or too much) housing when affordability is the criteria of interest. Of course, these metrics don’t resolve the debate between those who want prices and rents to rise (home sellers and landlords) and those who want them to come down (home buyers and renters), but at least they provide a common empirical grounding.

People per Dwelling (a.k.a. residential crowding)

People per dwelling provides a different class of metrics for thinking about whether there’s enough housing, focused on residential crowding. Fundamentally these metrics ask if there are there enough dwellings to “fit” the number of people we have in a given place. Of course, this is only a potential measure of fit when houses are mostly distributed by the market. Wealthy people probably take up way more room (and rooms) than they need, while poor people more often end up stuffed together. There are two solutions to this situation: one is to ration housing, so that extra rooms are shared around. We see this only for the small proportion of our housing stock that’s non-market housing. Market housing isn’t at all rationed according to need, but instead doled out by wealth-weighted desire (money). The other solution, far more common across North America, is to outlaw too much residential crowding via maximum occupancy codes and sharing rules. This is very common, and in the absence of rationing housing according to need this tends to lead to the exclusion of poor people altogether.

Across most of Canada residential crowding remains low. This is especially true of those places with strong municipal regulations against crowding (e.g. fire codes and occupancy standards) and market distribution of housing. Non-urban, non-market housing, especially on First Nations reserves and in Nunavut, where rationing is more common, tends to be where we see the greatest number of people per dwelling. Here we see a real failure of investment in non-market housing to match occupancy standards observed elsewhere, though differences in family sizes and cultural openness to different rules for living together also play a role.

While crude aggregate crowding metrics can help reveal the lack of housing across reservations and Northern territories, they don’t tell us much about differences between metropolitan areas, which stick together in a relatively narrow range between two to three people per dwelling. The narrow range reflects how crowding is both generally outlawed and also discouraged by market mechanisms distributing the vast majority of housing (above). We also know residential crowding is on the decline in most places, resulting from long-term declines in childbearing, family size, and tolerance for living together combined with the general rise of affluence, occupancy standards and enforcement. Correspondingly, crude aggregate crowding metrics should probably not be used to answer questions about whether metros or municipalities have enough housing. They don’t tell us much.

Despite their problematic nature, people per dwelling metrics are commonly used to answer questions for which they’re not suited. Several municipal planners and even a couple of academics have used new persons (or new households) per new dwelling as a metric for whether a place is adding enough housing. Given constraints on crowding and market mechanisms, this is equivalent to asking whether housing supply is meeting demand (as above). Of course it is! By definition, local housing is ALWAYS meeting demand (at some price). Similarly, by definition if you count all of the housed people added and all of the new housing added in a given location, there will always appear to be enough housing added to house everyone (at some level of crowding). After all, only housed people are counted, meaning only the net “winners” able to out-compete others for the dwellings being offered by the market. Net “losers” not provided housing by the market don’t get counted at all! Put differently, if price metrics weigh the whims of the wealthy too high relative to the needs of the poor (a valid critique), then crowding metrics ignore everyone without local housing entirely: all the people who want to live in a place but are prevented from finding housing there don’t get a vote.

Contributing to this fundamental problem, net housing additions are also often poorly counted, either because of changing census methods or failure to combine completions data with demolitions data. This has proven a particular problem for analyses that take for granted how people distribute themselves into households and simply compare new households to new dwellings, taking the leftover number of new dwellings as “empty” excess (in this case, the number of net new housed households can never exceed the number of net new dwellings except in cases where there were previous “empty” dwellings). Given the myriad of problems involved, crude aggregate measures of new persons or new household per new dwelling are especially poor metrics for determining if metro areas or municipalities are building enough. The answer they provide, by default, is practically always “yes.” For similar reasons, reinterpreting past census counts into population projections as the basis for how much housing development to allow is backwards. In high demand places, the availability of housing limits population growth rather than the other way around. Planners and academics should stop using metrics that count only local winners as answers to whether we’re building enough housing.

What about more refined measurements of crowding at different levels of analysis? These are often worthwhile to consider. Given a few strong assumptions about the privacy needs of people while they sleep (practically the least interesting activity they undertake), residential crowding can be measured in terms of bedrooms rather than simply dwellings. Measured at the household level, we can get a sense of how many households are living in dwellings that force more than two people to share a bedroom. We can come up with even more elaborate rules, as in the Canadian National Occupancy Standard, where we assume people need one bedroom per sleeper, but we allow couples to share with each other, and kids to share with other kids (below age 6) and other kids of the same gender (below age 18). Applying these rules more clearly demonstrates the residential crowding on First Nations and in Nunavut. But once again, the metric tells us little about most municipal and metropolitan variation.

We can also refine measures to explore residential sharing at particular ages. When do children leave home? It might be that adult children remaining living with their parents is a sign of need for more dwellings. This is tenuous as an indicator (some children want to stay home, others do not), but interesting!

We can also count individuals without dwellings. This is a form of mismatch. Given the current distribution of housing, how many people are going without? Homeless counts offer an important signal about whether there’s enough housing: if we can count people who are homeless, then there is not enough housing. But this is a broader problem with inequality. Bringing more housing to market may not solve the problem, especially since the demand for housing isn’t just local, and the whims of the wealthy will continue to outweigh the needs of the homeless. Homeless counts are an especially good signal of the need for more non-market housing. Of course, another good signal of the need for non-market housing are the waitlists for cooperative, subsidized and supportive housing. Effectively, both homeless counts and non-market housing waitlists register urgent local needs not being met by the market distribution of housing. That said, homeless counts and waitlists suffer some of the same problems as other crowding metrics insofar as they only tend to record housing need that’s already in a given locale. But people fall in and out of need and they also move. The dire needs of refugees in tent camps tens or thousands of miles away do not get considered, even if those refugees might eventually show up in a municipality. As a result, there remain difficulties in determining just how much need to meet: there are probably no ethically satisfactory stopping points. And even if there were, under rationing systems of all sorts, housing waitlists can grow to enormous lengths. As with attempts to preserve market affordability, we can know we need to build a lot more non-market housing without necessarily knowing when (or if) we should stop.

Finally, returning to the notion of “excess” dwellings, we can also count dwellings without people in them. This is ultimately a bad measure of whether there’s enough housing without a) greater knowledge of the reasons why units appear to be empty and without b) a corresponding will to expropriate “bad” empty units and ration them out according to need. Speaking to the first point, if dwellings register as “vacant” and available to the market (e.g. rental vacancies or unoccupied sales listings), then these dwellings will help reduce prices (see above). If they’re not on the market, they may reflect development processes (pre-demolition or recently constructed dwellings) working toward adding more housing. A variety of other procedural transitions (deaths, inheritances, etc.) may also account for dwellings without people in them before we get to second “vacation” residences (whims of the wealthy, etc.), and alternative uses (AirBnBs, etc.). To the extent these kinds of unoccupied dwellings are rising, they may result in reductions to the market supply of housing, pushing up prices for dwellings that remain. Finally, keeping housing empty and off the market may result from attempts to reduce transaction costs and/or speculatively manipulate market pricing. This is of greatest concern from the standpoint of maintaining market stability and affordability. The diversity of reasons that dwellings might show up as unoccupied means that, by itself, keeping track of unoccupied or empty dwellings is probably a bad measure of whether the market is building enough housing. After all, empty units may be adding to supply or detracting from supply, with varying affects on affordability, depending upon whether they’re on the market. That said, like homeless counts, “empty home” counts can be useful as an indicator of how the market is working to match people to dwellings (given underlying and unmeasured inequality). Moreover, empty homes can be bad in their own right, potentially deadening neighbourhoods. A Lincoln Institute report defines thresholds at which vacancy becomes a problem, with “low” vacancy (a problem for facilitating moves) below 4%, “reasonable” vacancy between 4%-8%, and high vacancies at 8%-20%. “Hypervacancy” (20% or more) poses special problems, especially in the case of declining cities. All major Canadian metro areas fit in the “reasonable range.”