The National Sample Survey (NSS) is a foundational statistical concept and a continuous program of large-scale sample surveys in India, initiated in 1950 to address critical data gaps for national income estimation and socio-economic planning. The first survey round covered only rural India, with urban areas included in the third round in 1951. The program was founded on the recommendation of Professor P.C. Mahalanobis, who is considered the father of modern Indian statistics, to provide reliable data on poverty, employment, and living standards for evidence-based governance.
The mechanism involves conducting nationwide sample surveys on a scientific basis, with a historical ten-year survey cycle that included quinquennial (five-yearly) surveys on employment-unemployment and consumer expenditure. The institution responsible for the surveys was the National Sample Survey Organisation (NSSO), formally established in 1970 under the Department of Statistics. A major change occurred on May 23, 2019, when the Government of India merged the NSSO with the Central Statistics Office (CSO) to form the National Statistical Office (NSO), which now operates under the Ministry of Statistics and Programme Implementation (MoSPI).
The NSS connects to key economic concepts like the estimation of Gross Domestic Product (GDP) and the Consumer Price Index (CPI), with recent reforms including the revision of the GDP base year from 2011-12 to 2022-23 and the CPI base from 2012=100 to 2024=100. Recent changes also include the adoption of digital platforms like Computer Assisted Personal Interview (CAPI) and the e-SIGMA system, which have reduced the data release time from 8-9 months to 45-90 days. Furthermore, the sampling design was modified from January 2025 to include a provision for generating district-level estimates, making the district a basic stratum for more granular data-driven planning. The surveys are now conducted under the legal framework of the Collection of Statistics Act, 2008, as amended.