Economists use a couple of terms that are very important for this concept.
The term convergence is the term that is used to
convey a narrowing of the proportionate gap of
a poor country and a richer comparison country.
Is the proportion of income per person in the poor
country relative to the rich country rising?
Is the poor country closing that gap?
If so, the poor country is said to be converging with the higher income country.
The opposite is divergence.
Divergence means that the poorer country in relative terms is
becoming even poorer when compared to the rich country.
Maybe the poorer country is making progress.
Maybe it's income per person is rising 1% per year.
But if the richer country is making even faster economic growth say,
2% per year, then the poorer country will have
a declining relative size in gross domestic product
per person relative to the higher income country.
So, we want to study whether countries are converging or diverging.
That will tell us a lot about whether overall differences of material life.
Life expectancy, health, education levels,
degree of urbanization are tending to narrow between the rich and
the poor countries or tending to widen.
I would say in this very complicated question with a very
diverse record of now 193 countries around the world,
so no one storyline that fits all.
We could say in broad terms that one part of the period of modern economic growth
has tended to be characterized by a kind of divergence.
And more recently, by a pattern of broad convergence.
What do I mean by that?
We're going to be studying how modern economic growth took of in
the Industrial Revolution.
And we know that until the Industrial Revolution began,
most of the world was poor.
Most of the world was rural.
The gaps of rich and poor countries were quite narrow not like the huge gaps today,
and then a take off started with the Industrial Revolution.
And with that take off, certain part of the world, relatively small part of
the world starting in England spreading to Great Britain more generally.
Spreading to Western Europe, the United State, Australia.
A very few other places initially experienced that
industrialization in the first part of the 19th century.
Most of the rest of the world remained poor and rural,
and the overall process was one of divergence.
The rich were becoming richer, because they were industrializing,
the poor were like they always were.
Eking out a survival in peasant farming in most of the world,
relatively untouched by the new inventions of the steam engine or
the railroad or the telegraph or the other technological advances
that help to set off the process of long-term economic growth.
One could say that the rich were getting richer and
the poorer were kind of stuck at the bottom and
the relative gap between the two was tending to widen,
then came a huge political phenomenon and that is the phenomenon of imperialism.
Because as Western Europe became industrial and quite powerful,
it took political control over more and more of the world.
We'll see that the British Empire spanned the world.
We'll see that other European powers took on more and
more imperial possessions, notably in Africa and in Asia.
This I think was a big setback to the potential of convergence.
Because when countries are dominated by other countries,
it's very hard for those who are in that subservient
position politically to undertake the kinds of
steps improving the infrastructure of the country.
Raising education levels that are crucial for achieving economic development.
And often, the imperial masters are not so
interested in the economic development of their possessions.
Rather, they're interested in taking out as many of the resources of those
countries as they can for the development of their own home industries.
I think it's fair to say that from the period of around 1850 to 1950,
the world was broadly characterized by economic divergence where a few
parts of the world were becoming richer and richer, more and more industrialized.
More and more militarily powerful.
Other parts of the world were stuck in poverty and many parts of
the world were stuck as the imperial possessions of European imperial powers.