THRESHOLD HYPOTHESIS
Threshold hypothesis is an offshoot of demographic transition theory (DTT). According to DTT, changes in mortality and fertility are caused by development and modernization. Yet, one may argue that in ancient society minor improvements may not have led any change in mortality and fertility. Improvement in people's condition must be substantial and perceptible. Thus threshold hypothesis attempts to operationalise how much improvement in socio-economic indicators is required for fertility to start declining or to decline to a given level.
According to Berelson there are certain threshold values of socio-economic indicators which should be achieved to lower birth rates. They are given in the table below:
Indicator |
Threshold value for Crude Birth Rate |
|
30 per thousand population |
20 per thousand population |
Adult literacy (percent) |
70 |
93 |
School enrolment, age 5-10 years (percent) |
55 |
69 |
Life expectancy (years) |
60 |
69 |
Infant mortality rate (per thousand) |
65 |
32 |
Non-agricultural labor force (percent) |
55 |
80 |
Per capita GNP (US $) |
450 |
1080 |
Females, never married, age 15-19 years (percent) |
80 |
100 |
|
|
