In a case of l’esprit de l’escalier, I just worked out the perfect parenthetical addition to this piece that was published in Inside Story, responding to a string of pro-natalist pieces in the New York Times and elsewhere. The central point is that the economic model in which strong young workers support elderly retirees is outdated and will only become more so.

A sharp fall in births during 2020 has provoked a wave of handwringingabout the implications of an ageing population. The decline can’t be attributed solely to the pandemic, since most of the babies born in 2020 were conceived before the pandemic began. However, it appears to have accelerated as the impact of the pandemic has been felt.

Some of the complaints reflect old-fashioned, not to say primitive, concerns about birth rates as an indicator of national ‘vitality’. But the main focus of concerns reflects a 20th century understanding of the economy that is deeply embedded in our ways of thinking and economic measurement, even though it is now almost completely obsolete.

The central assumption underlying these concerns is based on economic model in which “societies are organized around the notion that a surplus of young people will drive economies and help pay for the old”.

The model in which the young supported the old emerged in the 20th century, and ended with the 21st. For most of human history, old people were expected to work as long as they could, just as children were put to work as soon as they were able. The very young and the very old depended on their families to support them.

The welfare state which emerged at the end of the 19th century changed this radically. On the one hand, children were excluded from the workforce and required to attend school until the official leaving age, typically around 14. Governments paid for the schools, but, for the most part, required parents to support their children as in the past.

On the other hand, the introduction of old age pensions meant that old people (most commonly those over 65) were now entitled to public support, sometimes though not always, subject to a means test. Pensions were paid out of taxes or contributions to social security schemes. Either way, the cost was borne by the population of ‘working age’, defined as 15-64. With a high birth rate, the age distribution of the population appeared as a pyramid, with a large working age population supporting a small group of retirees.

The model underlying the desire for a population pyramid is one in which physical work predominates. Young and strong, needing only on-the-job training, workers leave school at 14 and immediately start contributing to the economy. By 65, they are worn out and ready for retirement. In this model, the more young people, the better.

To see that this assumption is problematic, we need only to look at US data on employment by age. At the turn of the century, the assumption described above looked reasonable enough. Around 60 per cent of young people aged 16-24 were employed compared to barely 30 per cent those aged 55 and over.

But by 2019, before the pandemic, the gap had mostly closed. Just over 50 per cent of people 16-24 were employed, compared to 39 per cent of those over 55. Many of the jobs held by young people are part-time and low-waged. By contrast, older workers are, on average, just below their peak lifetime earnings, reached around age 50.

Taking these facts into account, it seems likely that mean earnings per person are already higher for the old than for the young.

The reality of a modern economy is quite different from that underlying the population pyramic. To become a productive member of the community, young people need post-school education, whether academic or vocational. That implies a large expenditure of resources, which may be paid for by government, parents or through loan schemes like HECS. Taking all these together, the proportion of national income allocated to education is stable or increasing in developed countries like Australia and the US, even as the proportion of young people in the population declines.

https://www.acer.org/au/discover/article/three-charts-on-how-much-australia-spends-on-all-levels-of-education

https://ourworldindata.org/grapher/us-education-expenditure-as-share-of-gdp-public-and-private-institutions?country=~USA

A return to high birth rates over the next few years would imply the need for a large increase in education spending. The payoff in terms of a more productive workforce would not be fully realised until the second half of this century, when the expanded age cohort entered the prime-age workforce in their late twenties and early thirties.

At the other end of the age distribution, official retirement ages have been abolished, and the eligibility age for the pension has been pushed to 67, with further increases in prospect. There is still a substantial group of manual workers for whom physical exhaustion makes retirement a relief. Attitudes that under-value older workers are still prevalent, with the result that many are pushed into retirement whether they like it or not. But for a large group of white collar workers, working past 65 is an increasingly attractive economic option.

A realistic model of the future workforce is one in which productive workers are mostly aged between 25 and 70. It’s unlikely that life expectancy will ever be much above 95. On that basis the typical person will spend about half their life in the working age population and the other 50 years evenly divided between education and retirement.

In all of this, I’ve focused on the age distribution of the population. Despite the concerns that have been expressed, the age distribution associated with a lower birthrate is unlikely to cause major problem.

By contrast, the implications of a lower birth rate for the the size of the world’s population are unambiguously beneficial. The world is already overcrowded, and the needs of a growing population are straining the capacity of the planet to support us. Even with falling birth rates, the worlds population is certain to rise between now and 2050.

By 2100, population might return to the current level of eight billion or perhaps a little fewer. The idea that we should push people to have more children in order this number, rather than making marginal adjustments to the economic institutions we have inherited from the 20th century, is simply nonsensical.

Here’s my latest email news.

Once again, I’m trying to combine exercise and fundraising, in this case for the MS Brissie to the Bay Appeal.

Please donate to help me raise $2500 for multiple sclerosis research and help for patients and their families .I’m running a marathon in June, so I’m going to go with virtual fundraising, instead of taking part in the physical ride. My aim will be to run 300km and cycle 500km over May and June, and to raise $2500. Feel free to suggest challenges I could undertake to encourage donations.

Vaccinations against Covid-19 have started in many countries. In lots of places, it’s been a chaotic mess but Israel has already vaccinated 10 per cent of its population. Meanwhile, in Australia we not only have to wait for an approval process, but for a lengthy planning period to manage such an exercise. I’m not a public health expert, but I could see the need for such a capability 15 years ago (see post below). How can we have missed the boat so badly on this?

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The most memorable answer to this question came from science fiction writer Harlan Ellison, who said “Poughkeepsie” (on checking Wikipedia, I learn that he died a couple of years ago).

But in the context of discussions about remote work, I’m interested in the claim that random physical meetings (the archetypal example being corridor or water-cooler encounters with colleagues) are an important source of ideas, and therefore a reason for not working remotely.

This seems to be the kind of topic for which the data will consist mostly of anecdotes and introspection. A marginal improvement is too look over my own list of publications to see if I can identify any where the source arose from some particular interaction.

Looking at my 100 most-cited papers in Google Scholar, most collaborations are the result of planning rather than chance. In pre-Internet days, most of my collaborations started from seminars and conferences I spoke at or attended because the topic was of interest, or else from direct approaches by a colleague, usually in the same department. From the early 1990s onwards, direct approaches mostly came by email, and work has been done the same way. In several cases, I have written joint papers before ever meeting my co-author(s), though in other cases in-person collaboration with one or two co-authors works better.

More interesting to me, are the cases where the idea has come from blogging. Some notable examples

• My Zombie Economics book. Starting with blog discussions, the idea for a book came from blog commenter Max Sawicky, and was picked up by Seth Ditchik at Princeton UP, who also commissioned Economics in Two Lessons and my current book-in-progress Economic Consequences of the Pandemic
• Cross-disciplinary collaborations with Henry Farrell and LA Paul both arising from my involvement with Crooked Timber
• This paper, which started with a comment on a blog post to the effect that “future generations” are in fact already alive (At least I think that’s how it happened. I could never locate the comment to acknowledge the source.)

It seems to me that that these are much more like the kind of serendipitous links that are supposed to be generated by water coolers.

Of course, academic research is a special kind of work, and I’m much more involved with the Internet than most of my colleagues (or, at least, a few years ahead of the general adoption trend). So, I’d be interested in anecdotes from others and links to actual research, if there is any.

There’s been some good news on the local vaccine front, with a UQ vaccine project passing safety tests and showing early indications of effectiveness. With so many projects going ahead around the world, it seems likely we will have some usable vaccines by next year. On the other hand, based on past experience with similar diseases like influenza, it seems unlikely that vaccines will be perfectly effective. So, we’ll be living with some kinds of restrictions for the foreseeable future.

The prospect of a vaccine has, unsurprisingly, raised a lot of concern about anti-vaxerism and vaccine hesitancy, not helped by Scott Morrison’s short-lived suggestion that the vaccine should be mandatory. While there has been a fair bit of handwringing on this topic, our experience with varying levels of restrictions means that we have a fairly straightforward solution to the problem.

The characteristic of a pandemic is that everyone poses some level of risk to everyone else with whom they come into contact. Restrictions impose costs but reduce that risk.

The same is true of vaccines. As well as protecting those vaccinated to some extent, vaccines help to reduce the risk that we will infect others. On the other hand, they hurt, they pose a (probably small) risk of side-effects, and even if they aren’t actually dangerous, they are scary.

The crucial implication of this is that restrictions and vaccines are substitutes. A vaccinated person leading a normal, pre-Covid life poses a risk to others that can be matched by an unvaccinated person operating under some of the restrictions we have all experienced so far. Similarly, a vaccinated person who observes the basic restrictions (social distancing, masks, handwashing) might be comparable to an unvaccinated person on Level 2 or Level 3 restrictions (no bars, restaurant dining, large family groups and so on).

Assuming that we can get an expert assessment of the risks, we can make vaccination a matter of personal choice: the vaccine and low-level restrictions, or no vaccine and higher restrictions. Just as with that other highly risky activity, driving, this could be implemented through a license. But of course, starting from scratch, most of us wouldn’t need a physical license – this could be done with a QR code stored on phones, something much simpler than the ill-fated CovidSafe app.

Of course, there will still be objectors, like those who refuse both vaccines and other measures like masks, not to mention unlicensed drivers. But we are already working out how to deal with mask-refusers, border-hoppers and others. Even if compliance isn’t perfect, we will have a solution that works for most.

Following up this CT post on health living,, everyone has their own story and their own health. That’s true, but we are all subject to the same physical laws. So, here’s my story and some thoughts on the physics.

I managed to lose about 12 Kg over a couple of years, almost entirely through exercise.

The basic physics is simple
(1) weight loss = (kilojoules burnt – kilojoules consumed)*k,
(2) kilojoules burnt = base metabolism + work done

where k ≃ 0.025 is a constant reflecting the rate at which your body converts kilojoules of food energy into kilograms of fat. If you can alter the right hand side of (1) through any combination of diet and exercise then you will lose weight.

The problem is that altering either of these, or even altering while holding the other constant is really hard. Dieting makes you tired and slows your metabolism. Exercise increases your appetite, and also encourages you to flop once you stop exercising. All that’s because your body isn’t evolved to lose weight easily. Hunger and fatigue are both adaptations to stop you doing that. And, even if you can shift (1) enough to lose some weight, (2) puts a limit on how much you can lose. Balance is restored by the fact that your lighter body takes less energy to maintain and move around.

The crucial thing is to find some change for which you have both the willpower to adopt it initially and the willingness to maintain it indefinitely. For me, as I said, that’s been exercise. I aim to burn 4000 kj (about 1000 calories) a day in addition to base metabolism, which implies about 100 minutes of vigorous aerobic exercise. That’s logistically feasible for someone with flexible working hours and no kids at home, but very difficult otherwise. And it takes a long while to get to the point where you really enjoy it. That’s why the experts mostly recommend working on diet. But, if you can manage it, I think exercise is the better way to go.

Now that the World Health Organization has finally endorsed a recommendation for wearing masks in public, it’s time for Australia to do the same.

The most important case is that of public transport including air travel. Urban public transport is vital, but until we take the necessary steps on masks, we will be stuck with recommendations to avoid peak hour travel, guaranteeing a return to private cars and congestions

The airlines have been the biggest transporters of the pandemic and have continued to behave irresponsibly, packing planes as full as possible without any requirement for masks. It’s time for government to step in and order them to require masks as a condition of travel.

Update: I checked and Rex is doing the right thing here, upsetting some passengers who want to be free to infect fellow passengers https://www.abc.net.au/news/2020-06-03/regional-express-passengers-upset-forced-wear-face-covid19/12312358