Secondary data

Also called: Secondary source of data · Topic: Geographical Data: Sources, Compilation and Processing · NCERT: Class 12, Ch 1 "Data - Its Source and Compilation"

Meaning

Secondary data are data that someone else has already collected, and that you take from published records (printed or put online) or unpublished records (kept in offices, files or registers). They matter because no geographer can count a whole country alone. Large studies of population, land use, climate and development depend on data that bodies like the Census, the NSS, IMD and the UN have already gathered.

Explanation

What makes data "secondary"

• The key question is who collected the data, not what the data are.
• Primary data: you collect them yourself, first-hand, through a field survey, an interview, a questionnaire or by measuring something.

• Secondary data: someone else collected them. You only take them from their records.

• The same table can be primary for one user and secondary for another.

• For the Census office, which counted the people, a Census table is primary data.

• For a student who copies that table from a Census report, it is secondary data.

• Two ways secondary data reach you:

• Published source: a record printed or put online for the public, such as a report, yearbook, bulletin or website.
• Unpublished source: a record kept in an office, file or register and not released to the public, such as a patwari's land register or a company's internal files.

Published sources: six groups

• 1. Government publications (Union and state governments)
• Census of India: published by the Office of the Registrar General of India. It counts the whole population: size, age, sex, literacy, work, housing and migration. The first Census was in 1872. Since then it has been a decennial census (held about every ten years). It gives data down to the village and town level.
• National Sample Survey (NSS) reports: the NSS began in 1950 [2]. It is a sample survey (it visits a carefully chosen sample of homes, not every home, and uses them to estimate figures for the whole country). Today the National Statistics Office (NSO) runs these surveys in rounds of one year or six months [2]. Rounds have covered consumption spending, employment, health and migration [2].
• IMD (India Meteorological Department) weather reports: daily, monthly and seasonal data on rainfall, temperature and the monsoon.

• State Statistical Abstracts (yearly figures for each state), District Bulletins (data for each district) and commission reports.

• 2. Semi- or quasi-government publications

• A quasi-government body is set up by the government by law but runs partly on its own.

• Examples: urban development authorities (master plans, land-use data), municipal corporations (city data on water, waste, roads, housing) and zila parishads (district-level panchayats, with rural development data).

• 3. International publications (UN bodies such as UNESCO, UNDP, WHO, FAO)

• Demographic Yearbook (UN): the UN Statistics Division has collected official figures for it since 1948. Each year it sends questionnaires to over 230 national statistical offices [3]. It covers population size and make-up, births, deaths, marriage and divorce [3].
• Statistical Yearbook (UN): general social and economic figures for the world's countries.

• Human Development Report (UNDP): ranks countries by the Human Development Index (HDI), one score built from health (life expectancy), education and income.

• 4. Private publications: yearbooks, surveys and reports from newspapers and private organisations.

• 5. Newspapers and magazines: fresh data on rainfall, floods, crop output and elections. They often repeat official figures, so check the original source.
• 6. Electronic media, especially the internet: now the biggest source of secondary data. Census, MoSPI/NSO, IMD and UNSD data are online. Online data are still secondary and published.

Unpublished sources: three groups

• 1. Government documents
• Patwari: the village-level revenue official who keeps the village's land records.
• Revenue (land) records show who owns each plot, its area, and its land use (which crop was grown, whether it is irrigated).

• They are the most detailed village-level data on land use and farming. Because they stay in registers, they are unpublished secondary data.

• 2. Quasi-government records: development plans and reports of municipal corporations and district councils that have not been published.

• 3. Private documents: records of companies, trade unions, political and non-political (apolitical) organisations and residents' welfare associations (RWAs). They help small, local studies, such as the workers of one factory or the households of one colony.

The two-step test to classify a source

• Step 1: who collected it? You → primary. Someone else → secondary.
• Step 2: if secondary, is it released to the public? In print or online → published. Kept in a file or register → unpublished.
• Worked examples:
• Census report used by a student → secondary, published (government).
• A patwari's khasra register (the register of plots) used by a researcher → secondary, unpublished (government).
• Human Development Report → secondary, published (international).
• An RWA's member list → secondary, unpublished (private).
• Your own household questionnaire → primary.

Where it occurs

• Census of India: the whole country, down to every village and town. Run by the Office of the Registrar General of India since 1872.
• NSS household surveys: all-India sample surveys since 1950, now run by the NSO under MoSPI [2].
• IMD reports: all-India weather and monsoon data, used in climatology studies.
• State and district level: State Statistical Abstracts in each state, District Bulletins in each district, and zila parishad data for rural districts.
• Cities: municipal corporations and urban development authorities publish master plans and city data.
• Village level, across India: the patwari's revenue records.
• Going digital: DILRMP. The National Land Records Modernisation Programme began in 2008. It aimed to digitise written and map-based land records [4].
• In 2016 it was merged with older schemes to form the Digital India Land Records Modernisation Programme (DILRMP) [4].
• By January 2026, about 99.8% of records of rights had been computerised and about 97.4% of cadastral maps (maps showing the boundaries and owner of each plot) had been digitised [4].

• Modern record rooms lagged at 72.5% [4]. In Sixth Schedule areas of Assam, Meghalaya, Tripura and Mizoram, digitisation is harder because land is often owned by the community [4].

• World: UN bodies (UNESCO, UNDP, WHO, FAO) and the UN Statistics Division, which gathers figures from over 230 national statistical offices for the Demographic Yearbook [3].

Don't confuse with

• Primary data: collected first-hand by the user (field survey, interview, questionnaire, measurement). Secondary data were collected by someone else. The test is who collected it, not the type of table.
• Published vs unpublished secondary data: both are secondary. Published data are released to the public (reports, websites). Unpublished data stay in offices or registers (patwari records, company files).
• Government vs quasi-government sources: Census, NSS, IMD and District Bulletins are government. Municipal corporations, zila parishads and urban development authorities are quasi-government.
• Census (full count) vs NSS (sample survey): the Census counts every person. The NSS visits only a chosen sample of households and estimates figures for the whole country.

Prelims Hooks

• The Census of India is published by the Office of the Registrar General of India. The first Census was in 1872, and it is decennial.
• The NSS began in 1950. It is a sample survey, not a full count. Today the NSO runs it in rounds of one year or six months [2].
• The Human Development Report is published by UNDP, not by the World Bank or the UN Statistics Division. The UN Demographic Yearbook has collected data since 1948 from over 230 national statistical offices [3].
• Municipal corporations, zila parishads and urban development authorities are quasi-government sources. Records of trade unions and RWAs are private, unpublished sources.
• Trap: the patwari's village land revenue records are government, unpublished, secondary data for a student. They are not primary data.
• DILRMP was formed in 2016 by restructuring the 2008 National Land Records Modernisation Programme [4].

Mains Points

• Planning needs good secondary data (GS-I population and settlement; GS-III planning).
• The Census and NSS give data down to the village and household level.
• Plans for housing, jobs and migration depend on them.

• Gaps or delays in these surveys weaken planning based on facts.

• Land records link geography and governance (GS-III).

• Old paper-based patwari records lead to land disputes and delays in mutation (updating the record after a sale or inheritance).

• DILRMP has computerised about 99.8% of records of rights (Jan 2026). But record rooms, re-surveys and the linking of land records with maps are still incomplete. Community-owned land in Sixth Schedule areas makes the work harder [4].

• Limits of secondary data, and the role of the internet.

• Different sources may use different definitions, years and units. Private or newspaper reports may be biased. So a geographer must check the original source and make the data comparable before processing them.
• Online portals such as the UN Statistics Division make official data easy to reach and help studies across regions and countries [3]. Even so, unpublished local records are still needed for village-level studies.

Related concepts

• Unpublished sources of data

Read more

• Secondary sources: published and unpublished