The Economist’s Free Exchange column drops in on the question of an economic motherhood penalty from childbirth. It is nice to see that the Economist correctly distinguishes between two distinct economic motherhood penalties, both of which can be traced to the interplay between evolutionary forces and modernity, where the latter in this case is defined as an environment with rapidly increasing returns to investment in human capital and education. The first, between fathers and mothers, emerge because the cost of child-rearing especially in the early part of a child’s life overwhelmingly falls on the mother, a conclusion which follows from Trivers (1972). This is true in terms of the cost during pregnancy and immediately after too. It is also true before we consider the possibility that the resource allocation trade-off for many women shifts in the wake of motherhood. The second motherhood penalty occurs between women. Put simply, in an economic structure where childless women have the ability to devote all their resources to somatic investment and take advantage of the above-mentioned increasing returns to human capital investment, the wage and wealth divergence between women who have many children and those who have none will widen significantly, at least in theory. For more on this, I cover the theory in more detail in my essay on fertility and sexual selection; see here.
Read MoreI had the opportunity earlier this week to sit down with the IIEA and Dan O’Brien to discuss the decline in global birth rates, population ageing and what it all means. Thanks to the IIEA for hosting me.
Read MoreThis 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.
Read MoreThis is the landing page for my most ambitious non-fiction project to date. My writings on demographics are scattered all over this blog—though my master’s thesis is a baseline for a lot of my thoughts—and so, incidentally, is the work of my late friend Edward Hugh on the same matter. Randy McDonald has been stalwartly keeping the old Demography.Matters blog up to date, an effort which is badly in need of a new more modern and well-publicised platform.
I have been thinking about and studying demographics and population dynamics for well over 10 years, and this is my attempt to synthesise my thoughts. I will warm up with a simple account of the demographic transition, posted below, before moving on to the principal components of this process; mortality and fertility. I will then, eventually, examine how demographics drive economic processes, principally via the effect of ageing on growth and capital flows, expanding on the work that I have already done. I will post this work in piecemeal fashion inviting comments as I go along before combining everything into a coherent volume. When Google first introduced its Blogger platform it did so, I believe, under the banner of perpetual beta, a spirit that I agree with. I will post a final, and fully edited, volume eventually, but I also want to draw back the curtain slowly and gradually, if only to keep up the publishing cadence on this site. The meaning of “landing page” in this context is no more than a repository for the list of references and the individual chapters, both of which will be updated here as I go along. Each chapter, however, will have its own independent permalink too.
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