C.P. Blacker' demographic transition model

There many demographer and have difference perspective on transition stages. C.P. Blacker has presented five stages of transition phase. These are as follow:

1. High stationary population: This stage is similar to Thomson and Notestein's high potential growth. In a very underdeveloped economy and traditional social system, the difference in the birth and death rates is negligible and therefore the population is almost stationary with irregular fluctuations. Famine and epidemic regularly take heavy tolls on life. He said that 22 percent of world population was at this stage till 1930.
2. Early expansion stage: fulfillment of food supply brought by higher yields in agriculture and better transportation prevent death due to starvation. Frequent famine and epidemic were under some control, medical facilities were extended to common man, preventive medicines put some check on infections diseases, death rate started to fall slowly but birth rate however continues to stay almost at the biological limit. As a result, the population starts to growth. C.P. estimated that 40 percent of world population was at this stage in 1930.
3. Late Expanding stage: birth rate starts declining quite sometime after death rate has dropped perceptible. As death rate started to decline fast, population started to grow fast as well. People started to realize that higher number of births in a family is no longer required. As children death rate continues to fall and income rise, parents become increasingly confident that fewer children will suffice to help in family business and care for them in old age. The cost of children to parents rises by the introduction of legislation for compulsory education.  The public opinion and propaganda by the state were in favor of adoption of a small family.

4. Low stationary stage:  both birth and death rates are very low. Like stage 1, the population almost is stationary with a large base. Increasing female literacy and employment lower the uncritical acceptance of childbearing and motherhood. Working women have less time to raise children. Birth control measures are universally accepted so increase the standard of living is very high. The result changes in the age structure of the population include a reduction in the youth dependency ratio and eventually population aging. By 1930, 14 percent of the population was in this stage (Blacker).

5. Declining population: highly developed countries are very high per capita income, are at this stage of transition. Whenever death rate exceeds the nearly stable birth rate, the country face under population. Such a situation experienced in stage 1 and could be replicated after stage 4. The population in these countries generally have adopted one-child norm. This negative growth rate is a temporary phenomenon and continuation of the situation may encourage immigration to support the production processes.