Posts in Economic Theory and Acadmics
Things to think about #7 - Glenn Loury, Life History Theory, LatAm fertility and Substack economics

I am a big fan of US economist and academic Glenn Loury. He is smart, honest and well-articulated. He is also not afraid of an intellectual scrap if he stumbles upon one. He is an indispensable public commentator and intellectual whose ideas and influence go far beyond the confines of race, and associated social issues, in the US where he has staked his claim to fame and authority most comprehensively. Glenn has an impressive back-catalogue of writing and citations, but the best way to get a sense of him is by listening to his podcast the Glenn Show, which can be found on all the usual platforms. I am also a big fan of his co-conspirator, John McWorter, a US linguist and public intellectual, with whom Glenn runs a bi-weekly conversation on his podcast, and Q&A for paying subscribers. It is a must-listen. On this occasion, however, I want to recommend Glenn’s recent discussion with Larry Kotlikoff, a US academic economist, in which they discuss the economic policy ideas of the two candidates in the upcoming US presidential election ideas, and the US economy more generally. As the title of the podcast goes; if only we had an economist in the White House!

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The fertility wars

The political flurry in the US over the virtues of parenthood and a high birth rate is part of a much larger cultural moment in which the debate on the significance of falling global fertility is pitting two increasingly militant and unyielding sides against each other. We have trade wars, culture wars, even actual wars; we can now add fertility wars to the list. When Elon Musk, a US entrepreneur and businessman, calls Ms. Harris an “extinctionist”, because she has linked the reluctance of young people to have children to “climate anxiety”, he means it, just as he means it when he concludes that “the natural extension of her philosophy would be a de facto holocaust for all of humanity!”

How to get handle on this? With difficulty, but in the end, hopefully with precision and clarity. First, I will briefly show that the fertility wars have been fought for a long time. I will then draw the contours of three separate positions in the fertility wars today—on the Conservative right, on the left, and a feminist perspective—before offering a suggestion on where this discourse goes next, and where it ultimately ends up, if we are sufficiently unlucky or un-attentive.

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Portfolio optimization with US large cap equity sectors

I am still in a quant-mood at the moment, so today I will go through some work I’ve done on portfolio optimization with US large cap equity sectors. I am doing this to augment my current MinVar framwork, which I use for my own investments. A quick re-cap on the basics of portfolio optimization, with advance apologies to PMs reading this and lamenting that I’ve missed something. Finance has two workhorse models; the tangent portfolio, which places the investor on the efficient frontier, where risk-adjusted return—or the Sharpe ratio—is maximised. Or the minimum variance portfolio, which offers exposure to the combination of assets with the lowest variance, or standard deviation, regardless of return. These portfolios often are estimated given a set of constraints, as I explain below. Assuming most portfolio allocation decisions start with one of these ideal models in mind—you either want to achieve the best risk adjusted return or the lowest volatility—the difference between the textbook models and real-time allocations is governed by the following layers of complexity.

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Delayed Gratification - Why are global birth rates falling, and does it matter?

This is the final chapter in the first part of my long-running demographics project. In the previous chapter I described the quantum effect of fertility, which hypothesises a negative relationship between fertility and rising incomes as parents substitute quantity for quality in their reproductive decisions and child-rearing. But can the quantum effect explain why birth rates in one country after the other appears to be stuck below the replacement level, and why global fertility will soon drop below that same level? The answer is no.

To understand current and more recent post WWII global fertility trends—broadly since the 1970s—we need to introduce tempo effects to the analysis. Tempo effects describe the tendency of women to postpone the timing of their first child. By mathematical logic, prolonged tempo effects can drive significant population ageing, but a more fundamental question is whether birth postponement also has a lagged effect on quantum, or more precisely, cohort fertility. This chapter discusses these question in the context of the hypothesis of a Second Demographic Transition, SDT, and presents a number of case studies to explore the specifics of recent fertility trends in key countries and regions. The chapter finishes by discussing the idea of a fertility trap, and whether the increasingly accelerating decline in global birth rates are a problem, drawing on the recent polarisation in the debate on this issue.

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