The Sample Registration System (SRS) is a large-scale, continuous, panel household demographic survey, not an act or a scheme, that serves as India's primary macro-source for reliable annual estimates of fertility and mortality indicators. It was initiated on a pilot basis by the Office of the Registrar General of India (RGI) in a few states between 1964 and 1965 and became fully operational across the country during 1969-70. The SRS was created to solve the problem of chronic inadequacy and low coverage in India's statutory Civil Registration System (CRS), which, despite the backing of the Registration of Births and Deaths Act, 1969, was unfit for producing dependable vital rates.
The mechanism of the SRS is based on a dual-record system designed to maximize the completeness of vital event recording through cross-verification. The system operates through two independent components: first, a continuous enumeration of births and deaths in selected sample units by resident part-time enumerators, such as Anganwadi workers or teachers; and second, an independent retrospective survey conducted every six months by a full-time supervisor. The records from these two sources are then matched, and unmatched events are resolved through field re-verification to arrive at a near-complete count of vital events. The SRS provides annual estimates for key indicators like the Crude Birth Rate (CBR), Crude Death Rate (CDR), and Infant Mortality Rate (IMR) at the national and sub-national levels.
The SRS is conducted by the Office of the Registrar General and Census Commissioner of India (ORGI), which functions under the Ministry of Home Affairs. It connects to the decennial Census of India as its sampling frame is periodically revised and re-framed to align with the latest Census data, such as after the 2011 Census. Unlike the CRS, which aims for universal legal registration, the SRS is a sample-based statistical exercise. The SRS has been continuously updated, with its sample units being redrawn after each Census to maintain representativeness. For instance, the 2024 report utilized a sample covering approximately 8.9 million individuals across 8,839 sample units. The SRS also produces special bulletins, such as the one used to estimate the Maternal Mortality Ratio (MMR), which was reported at 97 per 100,000 live births for the period 2018–20.