Economic Growth and Development

Population: the basic concepts

The total fertility rate (TFR) measures the number of children born to a woman
during her lifetime if at each age she were to bear children in accordance with
the currently prevailing age-specific fertility rate. For simplicity the TFR is
calculated assuming that there will be no future changes in age-specific fertil-
ity rates so the measure will inevitably be an overestimate in those parts of the
world where fertility rates are likely to continue falling. The mortality rate is
the number of deaths per 1,000 per year of a defined population, infants, chil-
dren, or adults. Migration is the difference between arrivals and departures in
a particular geographic region. So population growth is the total impact of
fertility minus mortality and net migration.
Migration has a big influence at certain times. Between 1820 and 1920 60
million people migrated from Europe to the Americas, Australasia and
Southern Africa. Britain in the 2000s experienced its biggest wave of inward
migration since the seventeenth century. An estimated 500,000 people
migrated from Poland to the UK when Poland joined the European Union (EU)
and border restrictions were lifted. Migration is not relevant for the world as a
whole, and does not have the same systematic relationship with economic
growth as fertility and mortality, so is usually left out of demographic models.

Population growth and the economy: the negative

Numerous theoretical arguments link rapid population growth to adverse
economic outcomes. Families may reduce savings to sustain consumption for
each household member. For the whole economy, lower savings reduces the
pool of investible resources which must be more thinly spread. For example
increasing primary school places rather than deepening education into second-
ary and tertiary levels. High fertility (repeated pregnancies) may undermine the
health of mothers and their ability to work outside the household to supplement

Population and Economic Growth/Development 81

Figure 4.1 Population growth as a proximate determinant of

economic growth

Figure 4.1

GDP growth

Investment

See Chapter 3

Household

savings

Population growth

fertility/mortality