Recording of data of bihs and deaths in a community continuously after 6 months survey is known as

Sample registration system Sample Registration system (SRS) - staed in 1960 * SRS provide reliable estimated of bih rate at national and state levels. * It is dual record system Enumerator : Continuous enumeration of bih and death rate. - Independent survey : Survey every 6 month by investigator supervisor. * It cover entire country major source of death information. Census : It taken usually at intervals of 10 year Civil Registration system : It is deficient in India. * Estimation to missing event by enumerator and supervisor using well defined technique know as "CHANDRASEKHARAN DEMMY FORMULA"