Yes, that’s essentially the stylised model I use – i.e. I understand the long-run history of GDP per capita growth at the frontier as a transition from stagnation (/a very low rate) into sustained growth at a roughly constant rate. And it is very stylised (and I allow that the take-off may have been quite gradual), but I still think it works quite well as a basic framework.
And I agree that Romer’s backwards projection implies that the rate of GDP per capita growth at the frontier has increased over time; but it doesn’t prove that this took the form of a constant acceleration across all of history, rather than a roughly discrete acceleration (described above).
I don’t yet think that the Maddison data supports the idea of accelerating frontier growth across millennia. I think we need better country and year coverage to establish that claim. Better country coverage because the country at the frontier changes over time. Even if we see constant acceleration in country X’s GDP per capita growth rate between (say) 1-1800AD, it is unlikely that it was consistently at the frontier. We need to splice together data from various countries to get a timeseries of frontier growth. And better year coverage to avoid us relying on data points which may just so happen to be at a low or high point in a fluctuating cycle. We might have a higher estimate of GDP per capita in country Y for AD1000 than AD1, but I’d need more convincing to interpret that as long-run growth rather than our data point for AD1000 incidentally being a good year (or at the high point of a cycle which may span generations) and/or our data point for AD1 incidentally being a bad year (/low point in a cycle).
Nice piece, thanks. I hadn’t noticed HC’s latest video, but am also a fan so look forward to watching the full thing.
An initial thought, though: there seem at least a couple of places where one can grant his facts yet argue his interpretation of these as “good” is backwards.
For instance, one can argue that lower preindustrial working hours reflect chronic underemployment and unemployment, one of that society’s chief problems, and that industrialisation alleviated this problem (and even that this was one of the great initial benefits of industrialisation).
And HC’s following point ought to be seen as evidence against the superiority of preindustrial life:
Essentially he’s just pointed out that living standards were so low that the majority of budgets had to be spent just on food.