I listened to a frustrating Sam Harris podcast about COVID policy yesterday. What struck me about these "expert" commentators was that they
kept finding reasons to link COVID policy back to Trump, which was weird, and
all but ignored the enormous age variation in COVID risk.
Both these seem like popular ways of thinking, unfortunately.
I want to comment briefly on the second issue. This should help explain why I support vaccinations for the elderly but feel strongly against vaccinating children, vaccine targets and mandates.
The risk of serious illness or death with COVID is far more age-skewed than most viruses. In the below figure I show this skew. COVID is a serious disease for the elderly.
I also plot vaccine risks in the dashed orange. You might not be able to see it because it is so close to the axis. For age 70, the benefit-to-cost ratio of the vaccine is about 250x (i.e. the blue line is 250 times higher than the dashed orange line). A great outcome and something anyone would be foolish not to recommend.
But exponential curves are deceiving. Let's zoom in on this curve for young age cohorts. I do this below (curve equation is 10^(-3.27 + 0.0524xage)). Notice now that we are way down near the vaccine risk. It's close. I show a broad range of risks and call this COVID curve the risk of serious illness. I do this because reality doesn't follow the neat equation I used to plot the curve and children are likely even lower risk than shown.
In short, because the age skew of COVID risk is so severe, these huge many-hundred-times benefit-to-cost ratios can reverse at low ages so that the costs are many times the benefits. This is why so many doctors are calling for a halt to mandates for vaccinating children.
We should let this well-known information about COVID guide us rather than politics and panic.
Not that long ago Germany as a whole featured heavily in this debate over planning rules and house prices. With Frankfurt topping the latest UBS real estate bubble index, and Munich at number four, we don’t hear much about that anymore.
Tokyo is another city where planning rules are argued to have led to cheap housing.
Have we all forgotten that Tokyo was the world’s most expensive city not that long ago and is famous for how small its dwellings are? It also has less than 50% homeownership.
Across the central 23 wards of Tokyo, there are only 19sqm of dwelling space per person. Only 22% of Tokyo households have more than 29sqm of space per person. Across the prefecture as a whole, there are about 30sqm per person of residential space.
Australia has about 90sqm of internal residential space per person—roughly three times as much as Tokyo. Australia would need to nearly triple its population without building a single extra dwelling to have the same "housing abundance" as greater Tokyo, and would still have way more private garden space.[1]
Yes, there is an overall trend in Japan towards more dwelling space per person. But this is driven mostly by the rise in elderly households, especially elderly singles. When an elderly couple remains in their home after their children leave they increase the floor space per person even if that young adult child moves to an apartment with less space than their share of space at their parent’s home. When one person from an elderly couple dies, they leave behind an elderly single-person household, boosting the floor space per person metric. Many countries whose ageing populations are not as advanced as Japan’s will also see this same trend automatically.
Another issue is Japan’s long period of deflation. CPI is up 10% in Japan in the past three decades, while it’s up 300% in the US, for example. Average wages have also been flat for decades. It is not a good idea to compare rents or prices in Japan without factoring in their unique wage and consumer price conditions.
Overall I’m not persuaded that a housing market more like Tokyo’s is desirable. On the more substantial point that relaxing town planning rules got that outcome, I find little evidence.
fn [1] I’m wary of charts like the one below since the only statistics I know about dwelling sizes rely on self-reported estimates by various ad hoc surveys by statistical agencies.
“When I use a word,” Humpty Dumpty said in rather a scornful tone, “it means just what I choose it to mean — neither more nor less.” ’The question is,” said Alice, “whether you can make words mean so many different things.” ― Lewis Carroll, Through the Looking Glass
An increasing academic and policy focus on housing supply has unfortunately not brought with it an increase in clarity over the meaning of words. Words like housing supply, demand, zoning, price and affordability, have come to mean whatever the authors want them to mean.
This is unhelpful.
I've put together in the below table various potential meanings of these catch-all economic terms, and the words I think we should use instead to increase clarity.
For example, economists should be crystal clear that the economic price of housing is the market rental price (i.e. the price that measures the amount of good and services given up to get that good). The sale price of a dwelling is merely the market’s judgement of the asset value of buying a rental income stream in perpetuity and is heavily affected by prevailing interest rates (capitalisation rates), land and property taxes, and expectations of changes to the asset value (capital gains expectations).
With such a variety of definitions, what can the phrase “an increase in the supply of dwellings relative to demand will reduce dwelling prices” actually mean?
The obvious and strictly true definition is when the terms mean
supply → market willingness to sell housing in this period, demand → market willingness to pay for housing in this period, and price → the sale price of a dwelling in this period.
This merely describes asset market bid and offer schedules. When there is a "supply shift" in these schedules that massively reduces prices, we call that a market crash (a topic that is also poorly understood). But the economics of housing stock change is more sophisticated than this.
Supply and demand might also mean number of dwellings and total population—completely different ideas from bid and offer schedules in asset markets, instead focussed on material quantities that are expected to move together.
Sometimes supply is used to mean zoned capacity (how much can build built within current zoning rules) and is often assumed to be synonymous with the absorption rate (how quickly the market will develop new housing subject to asset market conditions). Changing zoned capacity does not necessary change the absorption rate, yet they are often described as one and the same thing.
Perhaps if we could describe what we mean more specifically we can start to allow the evidence to support or disprove theories about how the housing and property market operate.
I'm open to improving and expanding the table with better, or more widely used, terminology and will update and refine it over time.
A video of my testimony to the inquiry is here (from 11:00:00)
My full written submission is here and my follow-up response to questions raised is here.
_____________
I believe I am one of the few witnesses who has worked for residential and industrial property developers, in government departments dealing with infrastructure charges and regulation, and now as a housing researcher.
To be clear, Australia has more, bigger, better dwellings per capita than any point in history. We are also building new dwellings at a near record pace in a period where population growth is the lowest in decades.
More housing is better than less housing. Absolutely. I agree.
The argument I disagree with is that private landowners want to build faster, but only pesky council and state government red tape is slowing things down.
While I certainly have many ideas for improving and simplifying the planning system I see this as a separate topic to housing affordability.
We’ve heard from previous witnesses that housing developers have a lot of trouble building on unzoned land. No doubt. The whole point of unzoned land is to not have development at that location and get it located in the zoned land. It’s hardly evidence of anything except that these developers are bad at their jobs, always buying the wrong land for what they want to build.
Indeed, they certainly appear to be terrible lobbyists. If what they claim is true about zoning keeping prices up, then lobbying for mass rezoning is financial suicide. It would vastly increase the number of competitors in their market and reduce prices, wiping billions in value from their balance sheets. What sort of industry lobbies for that?
Perhaps this story is a lie.
In 2003, the AFR ran the headline “Brisbane running out of land for housing”, with land for housing expected to run out by 2015 according to the same expert lobbyists who have attended this inquiry. Yet detached housing lot production was 30% higher in the 6 years since 2015 than in the 6 years prior.
Are they terrible at their jobs? Or just telling stories that conceal the true nature of property markets?
Remember, only landowners can choose to make planning applications. Only landowners can choose when to build homes. Councils don’t do this. There is no speed limit to building new housing in the planning system. Planning regulates the location of different uses and densities, like road lanes regulate locations on the road. Density (dwellings per unit of land) and supply (new dwellings per period of time) are completely different concepts. More density does not equal faster supply.
The key issue at stake in this debate is that land is an asset. It is therefore priced like one. This is why when it is a good time to buy it is also a good time not to sell.
This is true for developed and undeveloped land. Stocks of undeveloped land sit on the balance sheet of developers, earning a return by growing in value while undeveloped.
The trade-off between the return from delaying developing land, versus developing now, creates a built-in market speed limit on the rate at which private landowners develop. As a previous witness mentioned, “… if you are a property owner or developer that had land that was consented and you hadn’t sold it a year ago then you are in a very strong position.” Builders might like to build faster, but landowners prefer to maximise returns on their assets.
We can see how this pays off with a case study of Jordan Springs, a Lendlease subdivision of around 2,000 housing lots in Sydney that took a decade to sell. I looked at the sales rates over time and saw that the average rate was only 45% of the peak rate (3-month average), though some periods had sales just 12% of the peak rate. The speed of developing new housing lots was far below the capability of developers and the capacity of zoned land. By selling at this slower rate, and capturing overall market gains in the form of higher prices, they made an additional $137 million on the project. Prices were 31% higher at the end than the start for land lots on a per sqm basis.
It would have been financially irresponsible of them to develop faster than they did.
I’m not saying that this behaviour is wrong, or a conspiracy, or even that it has major price effects. The stock of housing only changes a couple of percent a year at the best and small changes to those small changes make tiny price differences. This is just normal market behaviour. This is why for the century prior to the existence of zoning we had the same issues of unequal access to land and housing ownership, only much worse.
The current housing asset price boom is a global one. Average prices are up 20% in the last year in the US, the same as Australia, and many places that were previously lauded as having flexible zoning, like Germany and cities in Texas, have had the highest price growth. What we are seeing is a period of global asset re-pricing, as intended by monetary policy.
If you really want more homes build them. Flood the market with a public housing developer—you know, just in case the private developers don’t do what they said they would. It might be a sensible insurance policy. No doubt the property lobbyists will find something wrong with this, even though it is exactly the outcome they pretend to be lobbying for—more competitors and lower prices.
A discussion about the best way to provide below-market-priced housing popped up on Twitter recently. Peter Tulip noted many of the limitations of such systems—queuing, quotas, qualifying criteria, etc—concluding that a cash payment to help pay market rents is an economically-efficient way to get the policy outcome of reducing housing costs to low-income households.
Many submissions to the Falinski inquiry call for “inclusive zoning”, “affordable housing”, “social housing” and similar programs. A central feature of these policies is rent control, with housing being allocated by a mix of queueing, bureaucratic formula and randomness. 1/6
I am not against providing such cash payments. They are clearly better than nothing. But the reason I believe governments should build and own some housing is that it provides a better bang for your housing subsidy buck.
Consider the two alternatives over a “tenant life” of say 30 years.
With cash rental assistance, the government pays, say for the sake of argument, $13,000 per year the first year. But to have a meaningful effect this must grow over time to reflect growth in rents and incomes. At a 2% growth rate, by year 30, the subsidy is $23,000 and over 30 years the total subsidy paid is $527,000. The present value of this 30-year flow of subsidy payments at a 2% discount rate is $374,000.
With public housing ownership, the government builds or buys a dwelling worth $500,000 today to supply that dwelling at a rent that is currently $13,000 below market rent per year (i.e. the same rental subsidy to the resident). The remaining rent paid by the tenant covers ongoing costs only. Like the cash rental subsidy, the gap grows over time to be $23,000 in the 30th year. Instead of $374,000 in present value terms, this option costs $500,000 today to build or buy the dwelling (much less if built on under-utilised publicly-owned land).
However, with public housing ownership, a government agency owns the property at the end of the 30 years. Over this period, the asset value grows. Even if it grows in line with the 2% growth of local incomes it means that the property is worth $890,000. In reality, because incomes at a location rise faster than the average (because cities expand), it is likely to be more. For reference, this is only a 76% rise in three decades; a conservative figure when compared to the 143% price rise seen in Australia’s capital cities in the past 18 years.
The table below shows a comparison of the two alternative ways of providing the same value of housing subsidy to a resident over 30 years. Although the public housing ownership option costs $500,000 upfront, today's value of the final sale price is $490,000, leaving a net economic cost of just $10,000. This approach gets 40x better value for the budgetary spend. If capital growth is closer to historical norms then public housing can more than pay for itself.
What we learn from this is that
The cost of rental assistance over the long term is not much different than simply buying a dwelling and giving it to the household ($374k vs $500k).
The cost of rental assistance over the long term is much more than providing the same rental subsidy via owning the property ($374k vs $10k)
Getting out of the housing ownership game over the past three decades and shifting towards rental subsidies has cost government budgets billions.
[UPDATE] I've updated the figures to reflect 2% growth of incomes and rents and 2% interest and made the spreadsheet available here. Play around with the numbers.
[UPDATE] People seem to think that interest payments need to be taken into account somewhere. They do not. Prevailing interest rates are incorporated via discounting.
[UPDATE] Thanks to Jago Dodson for letting me know that a 1993 review by the Industry Commission (now Productivity Commission) ranked public housing first in terms of efficiency and cost-effectiveness out of a variety of alternative housing subsidy approaches they assessed.
[UPDATE] Thanks to Vivienne Milligen for letting me know that the 1989 National Housing Policy Review found similarly—that public ownership of housing is the lowest-cost strategy for housing poverty relief.
Part of political theatre that comes with rising dwelling asset prices is to fake concern for the non-homeowners. In the past two decades, this has taken the form of blaming supply and town planning for the fact that investors arbitrage returns and leverage into housing when interest rates fall.
It is nonsense from top to bottom.
We know this because the most recent of many UK reviews into housing supply concluded that it was not desirable to implement any new incentives for housing developers to build faster if that meant they had to accept lower prices.
The Letwin review of housing build-out rates was weird.
After learning that private landowners don't voluntarily flood the market to depress prices, they then decide that any policy to change that would be bad.
We know this because a 2004 Australian review concluded that the stock of housing changes by such a small amount each year that even very large changes to the rate of new supply will have small price effects.
From way back in 2004 when the Productivity Commission looked at the evidence and concluded that higher rates of new housing supply can't change prices much. https://t.co/yAD7CZSNVQpic.twitter.com/qPtpuLC7K1
We know that it suits vested interests in the property market to focus the debate on non-solutions that provide them windfall gains in the form of rezoning.
Housing markets are quite easy to understand. The difficult part is first unlearning all the nonsense that fills the newscasts and journals.
Australia’s latest inquiry into housing supply has begun. I took the chance to make a submission outlining my views on the housing market and writing a document that I hope provides some lessons about how to understand housing.
There are more, bigger, better, dwellings per capita in Australia in 2021 compared to any point in history.
Multiple government inquiries at all levels over the past two decades have ostensibly sought to find the cause of house prices hidden in the pages of local zoning laws.
Dwellings are assets and are priced based on financial market conditions.
Density (dwellings per unit of land) and the rate of supply (new dwellings per period of time) are conceptually different but often confused in housing supply discussions.
This submission argues that market housing supply has exceeded household demand. State planning systems have flexibly accommodated new supply while regulating the location of different types of dwellings.
Compared to household incomes and rents, the cost of buying a home (measured by mortgage payments) in 2021 is historically cheap. This is due to lower interest rates and is why intercensal homeownership is expected to rise in 2021. However, asset price adjustments will mean that this situation will not persist.
Taxes on property are efficient and fair and do not add to housing costs but rather subtract from property values.
Affordable housing is cheap housing. Cheaper housing means lower rents and prices. Any “affordability” policy that reduces market prices will remove billions in landlord revenues each year, transferring that value to tenants, and trillions in housing asset values, with that value transferred to future buyers.
Fostering parallel non-market housing systems, just as public healthcare provides a non-market medical system, can be an effective way to improve housing affordability.
There are no local, international, or historical examples of planning reforms leading to cheaper housing. Indeed, a Productivity Commission review concluded “given the small size of net additions to housing in any year relative to the size of the stock, improvements to land release or planning approval procedures, while desirable, could not have greatly alleviated the price pressures of the past few years.” (p154)
The GAMSAT is an entrance test that all prospective students to medical schools in Australia must take.
I want to use a hypothetical scenario about this test to understand how it might be possible to determine whether it constrains the rate at which new doctors are trained.
The hypothetical
Some people say that this test affects the total stock of doctors and hence the price of medical services.
You have the following information and are asked whether this is a potentially important concern.
In addition, you know that
Only those with a bachelors degree are eligible to take the test.
The number of people graduating with bachelors degrees each year is nearly a consistent 20,000 per year, adding to a large pool of candidate test takers.
Those who do not pass the GAMSAT can re-sit the test as many times as they like in subsequent years.
Those who pass have the option, but no obligation, to attend medical school.
You must re-sit the test if you do not go on to medical school within three years.
100% of those that decide to attend medical school complete it and become practising doctors.
You are asked to advise whether the pass rate contains information about the degree to which the entrance test determines the stock of practising doctors. Some say the high pass rate and ability to re-sit the test shows that the GAMSAT test is not a constraint on the supply of doctors.
Let us think this through.
The system perspective
The first thing to do is get a good understanding of the system with the numbers involved. The below diagram shows how the stock of potential candidates flows through the testing system to become doctors. There are three decision points.
The choice to take the GAMSAT test
The pass/fail choice
The choice to proceed to study after a pass
I draw these choices as taps that control the flow of “water” into the “buckets” (stocks of people at each stage). Notice that two of the choices return the people back to the pool of candidates—the pass/fail, and the study/delay choices.
Quite clearly the most important choice in getting water from the stock of potentials to the stock of doctors is the choice to sit the GAMSAT test in the first place.
This choice has by far the biggest effect on the outcome, with its variability accounting for the variation of flows through the system by a magnitude of 16x. One year 50 people took the test. One year it was 800.
None of this variation appears due to the GAMSAT test as the pass rate is unchanged and the choice to proceed is unchanged (we will return to this assumption).
By looking at the system in this way we can see that the maximum amount of additional doctors getting through the process by removing the GAMSAT test is 6%. It is likely to be less than this because those who fail often repeat the test.
You conclude that the GAMSAT test is at most an extremely minor factor influencing the rate of supply of new doctors.
A new argument
However, some argue that there is no evidence in the 94% pass rate that the GAMSAT is not a major constraint.
The argument is that the existence of the test reduces the number of applicants. Those who are likely to fail will know in advance and choose not to take the test. Therefore, even if the pass rate was 100% the GAMSAT could still be a major restriction on the flow of new doctors. It might be a plausible assumption that the variation in the choice to sit the test is explained by the number of people who believe they will pass it.
So we have two potential mechanisms of actions of the GAMSAT test.
A direct effect due to the pass rate
An indirect effect due to reducing the number who choose to take the test
How could we tell if the second mechanism was important?
We could look further up the system and see if the variability of the choice to take the test is related to factors regarding the test stringency, or other factors. But how would you measure test stringency if not for the pass rate?
You would need a third variable that measures test stringency that is unrelated to the pass rate, and that correlates closely with the number of test-takers. Possible? I’m not sure.
The problem is that if the second indirect effect dominates, then what are we to make of variation in the pass rate? What if a 10% pass rate is the norm, and that falls to 5% when the number of test-takers is high? This would surely indicate that the indirect effect is minimal and that people do not have a good idea of whether they will pass in advance. Or that they are willing to take the chance even if they have a good idea in advances.
Whichever way you cut it, the presence of an indirect effect surely must show up in the pass rate to some degree.
What have we learned?
It seems logical that there is information in the pass rate about the degree to which the GAMSAT test can reduce the flow of new doctors compared to if the test did not exist.
In the real world, and not the hypothetical I described, the pass rate for the GAMSAT is about 20-25%. In fact, the pass rate is itself determined by a quota on new university places. The test doesn’t constrain new doctors because the university quotas do it, and that quota determines the passing grade and hence the pass rate.
The reason for explaining this is because this post is not about medical school. It is about town planning. The “entrance test” in the planning system is a planning application, which is required to (re)develop a property.
Many argue (e.g. point 4 here) that just because 90%+ of the planning applications are approved that this doesn’t indicate there is at most a small effect on the rate of new housing supply. They argue that the indirect effect dominates and that’s why the approval rate is high.
But this leaves us with a conundrum. We know that a property with a planning approval is worth a lot more than one without. Therefore there is a large payoff to getting an approval. Just like there is a large payoff to becoming a doctor.
Yet candidate medical students are willing to sit a test with a near 80% failure rate, often repeatedly, to get that payoff. However, property owners are not, even though the payoffs can be worth tens of millions of dollars or more.
While an indirect effect surely exists in both medical school entrance tests and town planning applications, the pass rate also contains information about the existence of this effect.
“There are two schools of thought… Science stands for healthy scepticism… asking for better evidence… Then you have a second school of thought that is public health… it has the stance that we have a crisis, we are like an army, the platoon must do this or that. Anyone who leaves the platoon must be shot down.”
I like the way John Ioannidis has characterised the COVID public health response. The science and scepticism approach has been overridden by the public health army approach, which has little need for evidence. I recommend his presentation in this video, which is the source of the above quote.
The two schools of thought might explain the “you are better than this” responses I sometimes get on Twitter when I raise concerns that the public health policy seems detached from the scientific and logical reality. I hope it’s because they want me in their army. I hope it’s not because they have given up seeking the truth.
For some reason, I have a brain that can’t stop trying to seek out contradictions and the underlying logic that makes sense of the world. Scientific scepticism seems hard-wired. For example, when I look at Australia’s superannuation system, logic forces me to conclude that the system as a whole makes funding retirement harder, not easier. So I say we should dismantle it altogether.
I predicted that house prices in Australia would rise in May last year and people scoffed. Someone told me I should hand back my degrees. But the underlying logic I saw was correct (or at least useful for prediction).
Being right when the mob is wrong is, unfortunately, never popular.
In fact, a good rule of thumb is that there is no new information when someone says something popular. There is a huge amount of information when someone risks their reputation to say something. This is why John Ioannidis remains one of the few experts whose words contain actual information. He risks his reputation to say them.
This blog post is about the scientific and sceptical school of thought on COVID policy. It provides a glimpse of the contradictions and the underlying logic I see at play. Some of my previous thoughts and comments on COVID policy can be found here.
Seeking logic and evidence
Vaccines are the path
The current marching song is that vaccines are the path to freedom. Recently promoted by the Grattan Institute, an 80% vaccination target gets discussed as the key to returning to normal life.
There are two problems with this. First, getting 80% of adults vaccinated is quite difficult and has only been achieved in a small number of places.
Second, highly vaccinated places are getting COVID, some more than at any time before (e.g., Iceland, Israel, San Francisco, with surely more to come). While vaccines appear to be reducing mortality rates from COVID, differentiating the effect of the vaccination from the effect of previous population exposure is quite a challenge.
It seems to only make sense to vaccinate the elderly given the risk relativities and the limited effect on transmission.
Blaming one side of politics or the other for the “botched vaccine rollout” looks like nonsense to me when the experience elsewhere is that the level of vaccination is not having a major effect on subsequent virus waves.
Masks work
The only problem with this idea is that you cannot see it in the population-level data. In fact, you cannot even see much evidence that masks work in surgical theatres. Here is a thread containing many studies showing they don't.
Masks have become political symbols. And people love it.
The seasonal resurgence of COVID across the US despite vaccination and masking is quickly turning into a political problem to be manoeuvred around, not a health issue. Yet more signs that COVID policy is not health-driven.
Vaccine passports
Another chant I hear is that vaccine passports are necessary. But if vaccines work, we do not need a vaccine passport. The vaccinated are not at risk and their presence in the population reduces virus spread regardless. If vaccines do not work, then a vaccine passport is not stopping the virus from circulating and spreading amongst the vaccinated.
Notably, the recent data shows that vaccines wear off and vaccinated people get COVID at quite a high rate compared to unvaccinated (perhaps as much as 80% after six months) and are likely to transmit at a similar rate. This is why vaccine boosters are being planned.
I cannot see how the current crop of vaccines gets anywhere near a reasonable benchmark for restricting movement. Most people when pushed seem happy that vaccine passports would be used as an incentive to get vaccinated rather than as a direct health measure.
R0 talk and “exponential” threats
Despite a high reproduction rate and infectiousness, many COVID Delta waves have fallen off dramatically with relatively low infections (e.g. India). R0 does not seem to give any indication of the final size of an outbreak.
Another big unknown in the modelling is the degree of prior immunity in terms of the variation in COVID waves over time and between regions (such as if previous local viruses conferred some protection in the population), and in terms of potential for reinfection.
Lockdown cost-benefit
The lack of discussion about costs and benefits from masks and lockdowns is mass willful blindness. When an attempt is made, or some concession is made that the approach of evaluating costs and benefits is sound, usually another panicked argument is substituted instead.
Way back in the early days of COVID we saw some appalling attempts at cost-benefit analysis. One was out by a factor of 1,000! You could not be more wrong if you tried. Despite this, these same people are pretending to have been right all along and are still being taken seriously by the media.
That basket case Sweden
Sweden had a roughly 5% increase in total deaths in 2020 with no vaccine and no lockdowns (98,000 against ~93,000 expected deaths). For context, total deaths increased 5% in Australia from 2015 to 2017 (144,000 compared to 137,000 due to a 1.5% increase followed by a 3.5% increase).
Sweden saw no increase in deaths in any age group under 50 years.
When faced with these facts some say Sweden did reduce mobility voluntarily and that made the difference. But this merely implies that compulsory masks and mass lockdowns are not necessary and do not make a difference. You cannot have it both ways.
Kids and vaccines
Plenty of medical experts and ethicists warn about the risks of vaccinating children. They are rightly cautious. If one death per million from the AZ vaccine applied to Australian children that would kill 7 kids if they were all vaccinated. How many would it save? Given the low risk of COVID in children that number seems to be roughly 14 to 20. Are you happy with that trade-off?
This paper estimates the likely range of vaccine-related deaths if 80% of 18-59 year olds are vaccinated at 17 to 153. Given how little vaccines seem to stop virus transmission these risks need to be carefully assessed.
Suicides
A concern of mine has been that lockdowns would result in a rise in suicides. Thankfully that has not happened, but that does not mean there is no harm from lockdowns. U.S. data is showing a 50% rise in emergency department visits by teenage girls involving suspected suicide attempts.
The material prepared for quarantining households is predicated on the fact that forcing people to stay in their homes for weeks on end will lead to people bashing each other. Recent surveys of domestic violence care agencies suggest this has been the case.
Surveys show huge increases in depressive symptoms during lockdowns. These human well-being costs are real.
Media reporting for the army
I want to also demonstrate how easily the media falls into line with the public health army.
You may have seen the below chart showing that death from the AZ vaccine is less likely than being killed by a lightning strike in any year. Did you ever question it?
I did not at first either. But once your logical mind is brought into action you have to ask some questions. This is a classic example of the media picking and choosing “facts” and repeating them until they become the truth. Here’s the AMA President repeating it. Expect to hear it in casual conversation.
But there are two problems with this “fact”. First, the AZ vaccine has seen 7 deaths in Australia from roughly 7 million doses, so that risk is closer to double the 0.5 per million presented. Much more for all side-effects. Second, a risk of 0.4 per million for lightning strikes implies about 10 lightning strike deaths in Australia per year. But in reality, it is usually less than 2 (average of 1.9 for the past decade). So this is overestimated by a factor of five.
These two corrections mean that the AZ vaccine is ten times more likely to kill you than lightning. This “fact” is off by a factor of ten. The vaccine risk is still low. But this is hugely misleading and certainly is not going to promote trust in authorities when the error becomes more widely known.
Do you think the author of the original article presenting this “fact”, or the editors at The Conversation, actually care? Nope.
I have been reliably informed that someone with a keen eye for statistics approached the author to request they update the chart with more accurate statistics (their original lightning strike stats were simply lifted from here). But no. No action. The editors prefer to keep the wrong statistic on this hugely important topic rather than issue a small correction. Off by a factor of ten is totally acceptable as long as you are marching with the public health army.
And what of the risk of people dying with COVID? Why not put that on the chart and make a decent comparison. There has been almost no attempt at putting COVID risk in context in the media.
Perhaps the reason is that the data doesn’t sing to the public health army marching song. Take the Swedish data again. For ages 0-19 the risk of dying from COVID after 18 months of community transmission including two waves of infections, mostly with no vaccine, masks or lockdown, was 3.7 per million (9 deaths out of 2.4 million population). On an annual basis that is 2.5 per million. If we partition the data to account for co-morbidities, a healthy young person’s risk of COVID death gets much lower. Lower than the one in a million risk from the AZ vaccine? Probably not. But not a big difference, and certainly not enough difference to warrant the calls for rushing to vaccinate children.
Another place the media seems to be wrong is the story that vaccines produce better immunity than recovering from COVID. You might have heard this or seen a tweet like this.
So let us check the source of this claim. Nope. The study has no comparison between recovery-induced immunity and vaccine-induced immunity. It does show that some well-known immune responses do wane over time after infection. But this natural immune response may still be more persistent than the response from vaccines. However different evidence would be needed to establish the relativities. That doesn't stop the authors from making this claim, which is strange considering that one of the findings is that there is a subpopulation of people with a super strong and persistent immune response. Could they be simply chanting the public health army marching song?
Predictions
All of this has been a long-winded way of saying that a lot of what you hear about COVID and vaccines and the effect of our policy choices is incomplete, misleading, or plain old wrong. The one part that does make sense is quickly getting vaccines to the elderly—the overwhelming evidence for this conclusion is why every place is doing it regardless of differing views on masks, lockdowns, vaccine passports or border controls. In my view, vaccinating the elderly is one of the few policy actions the evidence favours.
The rest of the actions only make sense if you are in the business of marching a public health army and don’t care where that army is going or how many of its own it loses along the way. Lockdowns cost a huge amount of lives, masks don't do anything at a population level, and vaccine passports make no sense given the type of vaccinations available.
If the underlying logic of COVID I have identified is roughly true, then I should be able to make some predictions. Here are some.
There will be a time in the next two years when Australia has a much bigger COVID outbreak than any yet despite being hugely vaccinated. Depending on the political fallout from 2021 we may even collectively take no action. No masks. No lockdowns. No border closures.
Australia will see a year with a 7% increase in all-cause deaths (about 10,000) in the next decade and no one will notice. Given the ageing population and the normal variation in deaths each year, this makes sense. I’m actually being intentionally bold on this prediction. Realistically a 5% increase (7,000 extra deaths), or 134 extra deaths per week, is more likely to be observed.
Vaccine passports of some sort will be enacted against all evidence. They will be cheered by the mainstream media as they justify all the terrible policies the public health army has forced onto us so far. No one will care that the vaccines wear off or that the vaccinated transmit the virus to a similar extent after six months or so. The public health army will march on from the vaccine race song to the vaccine passport song, to whatever else keeps the marching going.
How the analysis looks to me
There is a spoof viking show called Norsemen on Netflix. In it, the characters talk about customs of life and death in a hilarious matter-of-fact way. I feel like I am living in a spoof Netflix show. The wonks are arguing the finer points of how to skin a virgin alive to please the gods while I stand by looking at the evidence that suggests rejecting the premise altogether. If only our policy choices today were a laughing matter.
I have a good track record of making “mad” predictions about Australia’s housing market that turn out to be correct.
In May 2013 I wrote that "if you have been holding off purchasing a home because of the risk of capital losses, then these risks are probably lower now than at any time in the past decade."
In May 2020 I argued that prices were more likely to rise than fall.
Here is another prediction. In the next fortnight, all Australian households will complete the census, as they do every five years. When the data comes out, it will show a slight uptick in the homeownership rate compared to the 65.4% from the 2016 census.
Why am I predicting this?
First, I want to look at the long term trends. Australia’s homeownership rate (share of households who own the home they live in, including if they have a mortgage) peaked in 1966 at 71.3%, having risen from 52.6% just two decades prior.
That boom in homeownership was brought about by heavy-handed government intervention in the housing market, including
rent controls that persisted post-war and incentivised landlords to sell,
public finance for first home buyers building new homes,
large scale public housing with tenant purchase programs,
along with many other interventions.
The market era from the 1980s onwards has seen homeownership rates fall from 70.4 % in 1986 to 65.4% in 2016.
However, there are ups and downs within the slight downwards trend over the last 30 years.
In a housing market, an imbalance of home buying between landlords and first home buyers leads to changes in overall homeownership. More landlords selling and more first home buyers buying is the only mechanism that changes the overall distribution.
Let’s look at those two elements of the market.
Since there are no available direct records of whether a property buyer is a landlord or first home buyer in any transaction, we can look at the patterns of mortgage finance.
The plot below shows the share of housing finance going to first home buyers and investors (sorry for no pre-2002 investor data).
The green shading shows the census periods with rising homeownership, and the red shading is falling homeownership, with the percentage point change in homeownership marked.
Since the last census in 2016, first home buyers have been large a proportion of all new mortgage lending, consistent with the 1991-2006 period of slightly rising homeownership (up from 68.8% to 69.8%).
But the stark change recently is the decline in investor lending in the market since 2016. In the 2011-16 period, investor lending was 39.4%, but since 2016 it has been 30.8% on average. Not buying and selling are somewhat equivalent asset investment options for investors. They both reduce the allocation to housing (just like not selling and buying keep more of an investment portfolio in property). We can then infer that the decline in investor buying is likely related to more investors selling.
This might not be the case. A confounding factor is the change in risk-weighting by banks for investor lending due to the fallout of the 2017-18 royal commission. Perhaps this means relatively fewer investors are selling compared to buying, but the overall level of activity fell substantially.
Another factor worth keeping in mind is the make-up of total households. The recent period of declining homeownership coincided with a period of rapid migration. These new households were more likely to be renters, at least for a short period. Most of this sub-set of renting households, including foreign students and temporary workers, have left Australia since COVID.
This combination of factors is why I am predicting a bounce in homeownership in the 2021 census.
Missing from the debate about the human cost of COVID lockdowns is an understanding of how societies produce health and longevity in the first place.
What are the economic and social ingredients of an historically unprecedented 83-year life expectancy in Australia, and are these at risk from our COVID response?
Over the past decade, Australian life expectancy grew one and a half years. That is 35 million life-years gained for a population of the current size.
The sum of all our economic and social life interactions can be thought of as a longevity machine. It produces economic wealth but it also produces health in the form of longer and happier years of life on average.
Economic and health outcomes are tightly related. A functioning economy pays for hospitals and clean affordable food and the roads and ports to ship food, medicine and other goods. Constructing sewage and energy systems, houses that keep us warm and safe, and schools that educate the next generation, are all parts of a functioning economy.
Sure, the economy is imperfect. Some components of the machine are a net negative for longevity, but the overall system does the job.
Delaying and disrupting the operation of the longevity machine costs lives. A day of delay to the machine in Australia costs 9,600 additional life years by pushing back longevity gains. By this metric, lockdowns reduce expected life-years by far more than might be gained from reducing COVID transmission.
In developing countries like India and Nigeria, where life expectancy is much lower (55 and 70 years respectively) but growing faster, each day of delay to their progress costs 1.4 million life-years. This is an astronomically high human cost that must be accounted for and compared to plausible COVID health scenarios.
This big picture longevity machine view of how social and economic processes create longevity might seem strange to some people. But it is a useful approach when looking at large-scale disruptions from lockdowns because it is surprisingly difficult to break out exactly what elements of social and economic life produce health outcomes. Is it diet? Friendship and social support? Education? Work quality? Family stability? Healthcare services? All have individual and coordinated effects, and all get disrupted by lockdowns in a variety of ways.
We can, however, look at some of the disruptions to different parts of the longevity machine to get a feel for how they cause irreversible reductions to health.
For example, prioritising COVID medical research above other diseases is likely to slow the longevity machine. The delay of other medical diagnoses, treatments and routine vaccinations will generate huge irreversible health costs for years. Due to border closures and supply issues from lockdowns, delays to global childhood vaccination programs are estimated to have already cost over a million lives of children under age five. Converting into life-years remaining at death, this cost alone would constitute more harm to human health than COVID.
We know that average population immunity to other circulating viruses has diminished due to declines in human interaction, creating new outbreaks in children of other deadly viruses such as respiratory syncytial virus (RSV). Global poverty has taken off, as has inequality within countries. Both are factors that reduce longevity.
Mental health is on the decline, binge drinking is up, teenage suicide attempts are up, and demand for counselling services is up. Surveys of well-being show unprecedented falls.
The freedom to travel and take memorable vacations are on the decline, reducing well-being. The kindness that happens in chance human interactions in daily life is down.
Childbearing has been delayed globally, meaning many women will now have fewer children than they desire because of this delay, a blow to their well-being.
Important life events such as high school formals, weddings and funerals, family reunions, birthday celebrations, and milestone sports and cultural events for budding young athletes, musicians and performers are all off the cards, with no chance of catching up for these losses in the future.
Australian governments have been extremely proactive with economic stimulus policies, providing fuel for the longevity machine to recover. But time cannot be recovered. Many lockdown losses, such as those described above, are locked in and will be felt for decades to come.
A public health mantra is that when combatting a single cause of death, one must avoid unintended health costs elsewhere, lest you inadvertently worsen overall health outcomes by your response. This is why pandemic plans prior to 2020 did not support large-scale lockdowns, and indeed, cited risks that behavioural changes might worsen virus propagation as well as health due to other factors.
But these diverse and often hidden health outcomes do not attract much media attention. Thinking about how the sum of social and economic activities as a longevity machine can show just how big a health risk even small disruptions make.
Q+A is not real life. Nor is Twitter for that matter.
In the days since my appearance I have received more than one hundred emails and messages from people from all walks of life across the country. These are not cranks. There are academics, scientists, and doctors, who are unable to speak up in their own organisations.
“l feel silenced by my occupation.” “I am a … working on vaccines…” “Please keep this confidential. I am a ... professor…”
I’ve had letters from young people pleading for some sense about the human cost of lockdowns, especially from Victoria.
The theatre of television is not where truth can be found. What people will say in public and what they privately believe are rarely the same. This is true even for Q+A panellists and hosts. Very few people have the luxury I do of following the data and evidence no matter where it leads. Most have reputations to protect, for themselves and their organisations.
Such people need someone else to speak up first. That is fine. Over the past decade or so I have become the guy that says the obvious before it is popular.
In doing so I’ve been called left-wing nutter, a right-wing nutter (make up your mind trolls), and many variations of “he’s an idiot”. Very witty. Often my views are later accepted more widely as being correct. But no one cares.
We don’t live in a world where truth matters. Making good predictions provides little credibility.
We live in a society of humans who are “group-ish” and loyal. One where people form their views socially, facilitated by story-telling. Being wrong with the group is better than being right but going against the crowd.
Here are a few things that have been on my mind regarding the state of COVID policy and analysis in the past few days. Before you dive in, you can read my earlier thoughts on COVID policy here.
Self-censoring at present makes sense for many people.
If you don’t, the power of big tech will do it for you. Bret Weinstein is no science slouch, nor are his guests, which include doctors and scientists (including the inventor of mRNA vaccines). Yet he has repeatedly been demonetised and censored on YouTube.
In this tweet YouTube is spreading deadly misinformation. It is creating the false impression that Ivermectin is ineffective against COVID. The evidence is discussed in the video. If there is disagreement on the evidence discussion is required. #FollowTheSilence#CensorshipKillshttps://t.co/uF7BjZ3tRP
Totally normal words and arguments by world-leading experts have become taboo. Herd immunity? Taboo. Great Barrington Declaration? Taboo. Our public health response has devolved into a social media political team sport, with no regard for facts and evidence.
In this social climate, who would stick their neck out in public?
Our new “health experts” are anything but
Eliminating COVID is a preposterous policy objective. Not only is it unlikely it is impossible to do nationally. The only public health objective that matters is maximising overall health and wellbeing.
Yet zero COVID is trumping all other considerations. The experts are not even trying to consider the cost. Lockdowns are free of health and wellbeing costs in their fantasy world. This is astonishing.
Here’s a clip with a variety of experts, including Sunetra Gupta explaining that although they are not as attention-grabbing as COVID deaths, the human toll of lockdown is very real.
No one cares about solving the problem. There is no plan.
Take a look at Ivermectin and the censoring of anyone who suggests that existing safe drugs should be used as COVID treatments. One might even suggest that there are financial incentives at play for pharmaceutical companies to make sure only their expensive new drugs are approved for COVID treatment.
Take a look at the logic being used to promote vaccines. The “experts” on Q+A simultaneously had the view that vaccines should not be compulsory and we should not open the borders until we are nearly totally vaccinated.
What if only 50% of people want to be vaccinated? What then?
Also, why should we vaccinate children when we know their COVID risks are minimal? Nearly 25% of the population are children, and COVID vaccines are not recommended for them.
We are told we must learn to live with COVID and future variants, but we are unable to accept that this means people will die from the disease. You cannot have it both ways. Have a logical plan, please.
No one cares about acquired immunity from disease
Experts worry that a perverse idea has spread widely—that people don’t get immunity from their body’s own response to contracting a virus. Yet saying the sensible reality that recovering from infection provides immunity gets you censored, no matter what your scientific credentials.
I said vaccinating children for COVID was crazy on national television. This provoked a response from the President of the AMA who wanted to imply something very different, but who ended up saying that the medical advice is that vaccines are not recommended for children. My views are totally in line with much of the medical profession. So why the need to put on a show to make it seem otherwise and give a distorted picture of the evidence to the public?
Even Harvard professors are not safe from censorship around sensible medical advice.
When making unscientific claims, media often refer to "health officials" or "experts" without citing anyone. I challenge @Twitter to name vaccine experts believing that everyone, including children and those with prior immunity from natural infection, MUST be Covid vaccinated. pic.twitter.com/tYhCjdKzgf
No one cares about killing poor children elsewhere
We know that the rollout of childhood vaccination programs has been delayed and disrupted, especially in the poorest countries. There is a huge cost to this in the form of avoidable child deaths. One estimate suggests that the disruptions due to border closures, logistics, and prioritising other vaccines and health supplies will cost the lives of over a million children aged under five. The longer lockdowns go on, and the more we devote health and science resources to COVID above other health issues, the higher this toll.
Are the figures in this study correct? I do not know. Their value is in providing a sense of balance. COVID is just one disease amongst many. Attempting to estimate the potential scale of other health issues that have been neglected is something that should have been front and centre of the policy response in Australia and globally.
Economic development makes people live longer
The investments that make people live longer are not usually direct healthcare investments. They are instead things like clean water, dealing with city waste, functional sewerage systems, reducing urban and local pollution, and clean food supplies. These have been proven time and time again to be what makes people living longer.
Now consider the cost of locking down India. Each year investments in these types of basic services create enormous health improvements of around 0.25yrs of additional life expectancy across the population (i.e. every four years life expectancy increases one year). Delaying this process with lockdowns is hugely costly there. A one year delay costs 0.25 life-years x 1.37 billion population = 342 million years of life—an astronomically high figure compared to even the worst-case COVID death toll.
The commentary on Australia’s economic performance is also amiss. The fact that economic activity recovered to its previous level does not mean lockdowns and border closures were economically costless. The counterfactual is where we would be today with no lockdown but with the stimulus actions we have seen, as the policy option to stimulate economic activity has always been available.
The stylised chart below shows what I mean. Comparing point A and B to show there is no economic cost is silly. Comparing point C and B is the only sensible approach.
The coming debate about COVID deaths vs lockdown deaths
Soon we will have a heated debate about how many lives were saved because of lockdowns. We will only have the debate about how many lives lockdowns actually cost in private, as those discussions will continue to be censored for a while yet.
Here is a quick overview of some of the mistakes of logic we can expect to see.
If recorded deaths by COVID are below excess deaths over the 2020-21 period, then that gap will be typically attributed to “missed COVID deaths”. This attribution is a wrong assumption. There will certainly be missed COVID deaths, and over-counted COVID deaths, but the gap can arise for multiple reasons, including lockdown deaths.
The Economist has already been implying these are all uncounted COVID deaths (see image below). They all seem to come from Asia and Africa (puzzling). I will be very interested to check back on their modelling exercise in 12 months time when we have more accurate records of what happened. Looking at how past predictions turned out is a great way to sense check claims, but something that the media rarely does.
This is an excerpt from a new paper of mine available here.
What is the source of rezoning gains?
The answer to this question relies on understanding the nature and extent of property rights. A core right of a property owner is to exclude others. A right holder of this type usually also has a residual claim to income generated in the space over which they have exclusionary rights (“pay to use this space or I’ll exclude you from it”).
But these rights are limited. They evolve as the law evolves, including zoning and planning law. Rights to access and sell minerals within a property’s exclusive space, for example, are not part of the private property rights bundle in Australia. They are instead owned collectively by States.
The value of private property rights is primarily determined by how much revenue can be generated above costs (excluding property rights costs) on a site at a particular location. The value of property rights is a residual, just as other assets like shares in company ownership represent residual claims on income. Whichever use of a site generates the largest residual income is its highest value use.
The revenue potential of private property rights is affected by market conditions, location-specific features, fixed improvements, and the nature and extent of the property rights bundle itself. Investing in new fixed improvements, like buildings and earthworks, can add to property value because they remove a cost to gaining revenue (remember, property value is revenue minus costs needed to earn that revenue at that location). The value of fixed improvements becomes “attached” to the property as they cannot be separated physically or legally from the property right to a location.
However, the value of private property rights can also increase due to external factors that are not due to investments made by the property rights owner. When this occurs, it is known as betterment. For example, new public works that improve the accessibility of a location will increase the value of those sites because they reduce the transport costs of using those sites to generate revenue. Similarly, when the law changes the nature or extent of property rights in a way that increases the revenue-generating potential of that site, such as with rezoning, the resulting increase in value of the property rights bundle is betterment.
Planning rules coordinate property uses across locations by defining property rights bundles. For this coordination role to affect property uses it must legally restrict some uses so that the highest value legal use is different to what might occur with a “no zoning” property rights bundle. Hence, there is an inherent conflict between maximising the value of any individual property and coordinating the location of property uses across a region.
The diagram in Figure 1 shows how betterment arises conceptually and how a tax on betterment transfers value to the public that would otherwise accrue to private property owners.
Figure 1: Betterment in the residual model of property value
The left column shows the value of the property rights at a site, such as agricultural or industrial land. That value is determined by the revenue that can be made from exclusively using that site, minus the necessary costs. The site’s property rights value is the residual.
Suppose the market value of the output being produced increases, such as the value of crops on an agricultural property, but all input costs remain the same. In that case, the site value rises to reflect the higher residual value of production on that site. The new site value and its betterment component from these external factors is shown in the second column of Figure 1. Another example is if the rent of a residential dwelling rises, but the costs of operating that dwelling remain constant. This increases the property value. Where a property tax system exists, some of the value gains accruing to property rights from higher market prices of production are shared with the public.
The third column of Figure 1 shows what happens if there is a change in the nature or extent of the property rights through rezoning. For example, if the previous highest value use of a site was industrial only because zoning laws prevented other higher value uses such as residential, then rezoning will change the highest value legal use of the site and hence its value. The difference between the “before” site value (V1) and the new “after” site value (V2) is betterment.
A flexible planning system presents opportunities to increase revenue from development by exceeding codified density limits and hence offers another way to generate betterment for a landowner. The betterment gained from exceeding codified planning density limits is just as real as the betterment gained from rezoning. It is why, despite cost, risk, and time involved, many property owners seek planning dispensation instead of complying with codes and gaining fast approvals.
Here is a useful way to conceptualist betterment. Rezoning adds an additional private property right to the previously owned bundle. The value of this new right is betterment, and it reflects what the market would pay if these new property rights were instead auctioned for sale to existing property owners.
The effect of a tax on betterment arising from rezoning is illustrated in the fourth column of Figure 1 using the 50% tax rate proposed in Victoria. A share of the betterment value is transferred from the private property owner to the public, reducing the private payoff from rezoning decisions and increasing the public’s share.
The size of betterment from rezoning can be extraordinarily large, often many multiples of the previous site value. For example, a well-situated industrial site in Sydney’s inner west was bought for $8.5 million, rezoned high-density residential, then sold again just a few years later for $48.5 million.
Rezoning at Fishermans Bend in Melbourne led to numerous sites trading at values many multiples of their previous industrial use values. At 320 Plummer Street, Port Melbourne, the 7,468m2 site formerly used as the Rootes (Chrysler) factory transacted in 2009 for $1.7 million with industrial zoning rights. After rezoning to high-density residential, an application was made and approved for the development of three towers containing 443 dwellings and 908m2 of commercial floor area. The property was subsequently purchased for over $11 million. Even after inflating the 2009 sale price to $3 million to reflect sale prices in 2015 for similar industrial properties, the windfall rezoning betterment is roughly $8 million, with the site trading for nearly four times its previous value.
Notably, betterment is not an additional cost to housing development. The value of property rights is a residual; after all, there are no input costs to these rights. Betterment merely reflects the change in the market value of the residual claim on income of the property rights owner, and taxing betterment merely transfers this value from the property rights owner to the community.
There is a common thread between the boom in lumber prices in the U.S. and dynamic models of housing supply.
That common element is that lower interest rates make it optimal to both harvest trees slower and to build new homes slower. Let me explain.
Take a look at the diagram below representing a forest with trees at different stages of growth.
The stock of potential timber from trees at different stages of growth is marked as Q. So 10 tonnes of large trees, 7 tonnes or medium trees, and 3 tonnes of small young trees. A total of 20 tonnes of timber there.
But each stand of trees with a different maturity has a different rate it grows per year. Young trees accumulate timber faster (proportionally) than older trees. The growth rates for the trees in each stand are marked—the oldest grow at near enough to 0%, the next at 5%, and the youngest at 10% per year.
Given this forest with a stock of 20 tonnes of timber, how much is optimal to harvest each year?
The trick to thinking about this question is to realise that the trees are assets, quite literally growing in value each year. When you harvest a tree you are swapping a "tree asset" for a "cash asset". The way to tell what is optimal is to compare the return from the tree asset that you give up to get the return from the cash asset. For example, if you can earn a 7% return from cash, you won't harvest a tree that is growing in size, and hence value, by 10% per year. It's a losing trade to give up 10% to get 7%.
In this forest, we harvest 10 tonnes this year if the interest rate is below 5%, and 17 tonnes if it is above 5%.
When it comes to forest management, lower interest rates mean slower harvesting of timber. If interest rates fall from 7% to 3%, then all the trees growing at a rate between 3% and 7% per year should be left to grow rather than be harvested and replaced with saplings. This is well understood when it comes to harvesting forests.
But it is not well understood when it comes to "harvesting housing development opportunities".
Undeveloped urban land is a lot like a tree—it grows in value without being developed (harvested). Like our forest, we don't just develop all land as soon as the revenue exceeds the cost. We optimise the rate per period to maximise value from the site (or set of sites). This is why developers stage housing subdivisions as much as possible.
A lower interest rate changes the trade-off between owning undeveloped land and getting cash from development. It makes a slower pace of housing development optimal, all else equal.
Not all else is equal, obviously. The price adjustment to lower interest rates generates demand that new housing supply responds to—interest rates are not the only factor. In the last 20 years we have relied on this temporary demand-boosting effect of interest rate reductions to generate supply, but this has led to structural low-interest-rate conditions that will not encourage supply when demand falls.
In housing, optimal harvesting is called the "housing supply absorption rate". I explain it here.
