Collection of Vital Statistics
The following are the five methods normally adopted for collecting data related to various vital events:
(i) Civil Registration System
(ii) Census or Complete Enumeration method
(iii) Survey method
(iv) Sample Registration System
(v) Analytical method
Civil Registration System is the most common method of collecting information on vital events. It is an administrative procedure followed by governments, to record various vital events occurring in their population.
In this method, occurrence of the vital events such as births, deaths, marriages, migration etc., are registered. Many countries adopt this system. Registration is done with the Authorities appointed by the respective government. In India, registration of births and deaths are made compulsory by legislation, through an act viz., "The Registration of Births and Deaths Act, 1969”. It came into force throughout the country through a gazette notification published in 1970.
Census presents a comprehensive profile of the country’s population. Census is conducted in most countries at intervals of ten years. The complete enumeration method normally covers data regarding age, sex, marital status, educational level, occupation, religion and other factors needed for computing Vital Statistics. However, all these information are available for the census year only.
Ad hoc surveys are conducted in areas where the recording of births and deaths has not been done properly and periodically, particularly in those areas where registration offices have not been established. However, survey records help to provide Vital Statistics for that region only.
Vital rates are required to monitor population growth, especially for the purpose of evaluation of family planning programmes in terms of their ultimate objective of controlling fertility.
Sample Registration System is adopted at both national and state levels in India to collect the following information:
(a) Infant mortality
(b) Age specific mortality rates in rural areas
(c) Sampling variability of vital rates
(a) Differences in birth rates with respect to education, religion, parity
(b) Sex ratio
(c) Seasonality in birth and death rates
It is generally not possible to conduct ad hoc surveys to assess the population at any specific period between two consecutive census years. Population estimates of any vital event at a given time can be obtained without ad hoc surveys applying analytical methods which use mathematical formulae.
Calculation of Vital Rates
Generally, rate of a vital event is calculated using the formula
Rate of a vital event = [ Number of occurrences of the event during the spe c ified period / Size of the population exp osed to the risk of the event] ×1000
Rates of vital events are usually expressed ‘per thousand’.