The Sample Registration System (SRS) in India is the largest demographic survey in the world covering about 1.5 million households and 7.3 million population. It has continued to be the main source of information on fertility and mortality indicators both at the State and National levels. Apart from the large sample size and geographical spread in most of the Districts, the system has a unique feature of dual recording, which involves collection of data through two different procedures viz., continuous enumeration and retrospective half-yearly surveys. The continuous enumeration and retrospective surveys are followed by the process of matching of the two records and subsequent field verification of unmatched and partially matched events. The system provides a cross check on the correctness and completeness of the events of birth and death listed by the two independent functionaries.
