The term demographic gap5 signifies the difference

The term 'demographic gap' refers to the difference between the birth rate and the death rate within a population. This concept is central to the Theory of Demographic Transition, which describes the historical shift of these rates from high to low levels. During the transition, the death rate typically declines first due to improved medical facilities and food availability, while the birth rate remains high [1]. This creates a widening gap between the two rates, leading to rapid population growth or a 'population explosion' [2]. As a country progresses through the stages of demographic transition, this gap eventually narrows when the birth rate also begins to decline, eventually reaching a new equilibrium of low birth and death rates [4]. This asynchronous timing of mortality and fertility declines is what drives the demographic dynamics of a nation.

Sources

1. [1] Indian Economy, Nitin Singhania .(ed 2nd 2021-22) > Chapter 19: Population and Demographic Dividend > Stage I > p. 559
2. [2] Indian Economy, Nitin Singhania .(ed 2nd 2021-22) > Chapter 19: Population and Demographic Dividend > STAGES OF DEMOGRAPHIC TRANSITION > p. 558
3. [3] Indian Economy, Nitin Singhania .(ed 2nd 2021-22) > Chapter 19: Population and Demographic Dividend > POPULATION AND DEMOGRAPHIC DIVIDEND > p. 557
4. [4] Indian Economy, Nitin Singhania .(ed 2nd 2021-22) > Chapter 19: Population and Demographic Dividend > CHAPTER SUMMARY > p. 576