Measurements & Trends and Patterns of Migration

• Migration is the spatial movement of population. It needs quantitative indicators for its volume, direction, intensity and effect on population change.
• Measures allow comparison between regions and periods, and show labour mobility, urbanisation and regional imbalance.
• Migration is the hardest of the three components of population change to measure. Unlike a birth or a death, a move has no single moment, can be repeated, and depends on boundaries and time limits that differ between sources.

Measurement of Migration

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Basic Concepts

• Stock and flow:
  • A migrant stock is the number of migrants present at one date, such as those counted by a census.
  • A migration flow is the number of moves in a period, such as a year or a decade.
• Lifetime migrant (place of birth): a person enumerated somewhere other than where they were born. This measure misses intermediate moves and return migration.
• Migrant by place of last residence: a person whose previous usual residence differs from the place of enumeration. It captures the latest move and is the better guide to current migration.
• Period (interval) migrant: a migrant by last residence who arrived within a stated duration, for example 0–9 years before a census. This gives a decade’s flow.
• Gross and net migration:
  • Gross migration = in-migrants + out-migrants. It measures turnover.
  • Net migration = in-migrants − out-migrants. It measures the balance.
• Return migration and circular migration (repeated to-and-fro moves) are poorly captured by one-time questions.
• Emigration and immigration are used for international moves; out-migration and in-migration for internal ones.

Sources of Migration Data

• Population census:
  • India’s census has recorded place of birth since 1872.
  • In 1961 it added the rural or urban status of the birthplace and the duration of residence.
  • In 1971 it added the place of last residence.
  • Since 1981 it has recorded the reason for migration: work, business, education, marriage, moved after birth, moved with household, others.
  • Census 2011 is the latest. The next census has a population reference date of 1 March 2027.
• Sample surveys:
  • National Sample Survey rounds on migration (the 64th round, 2007–08, was the last full one).
  • The Periodic Labour Force Survey (PLFS) 2020–21, which also measured temporary visitors after the COVID-19 lockdown.
• Population registers in the Nordic countries, the Netherlands and Japan record every change of address, giving exact flows.
• Administrative records: visas, residence permits, border crossings, passports, India’s eMigrate emigration clearances, refugee registrations (UNHCR).
• New data: railway ticketing, mobile-phone roaming and bank data. A 2024 study for the Economic Advisory Council to the Prime Minister used these to track domestic flows between censuses.
• International estimates: UN DESA’s International Migrant Stock (based on foreign-born or foreign-citizen counts) and the UN’s World Population Prospects (net migration).
• Limitations:
  • Definitions of migrant, time threshold and boundary differ between sources.
  • Boundary changes inflate counts: new districts and states turn short moves into “inter-district” or “inter-state” ones.
  • Only one reason is recorded per migrant, usually the woman’s marriage or the head of household’s job.
  • Seasonal and short-term moves are missed by census-type questions. Irregular migrants are undercounted.

Direct Measures (Rates)

• All rates are expressed per 1,000 of the mid-period population (P) of the area. IM = in-migrants, OM = out-migrants.

• In-migration rate:
  • High in urban centres, industrial regions and growth poles.
  • It reflects pull factors: jobs, education, infrastructure.
• Out-migration rate:
  • High in rural, drought-prone and backward areas.
  • A high rate often signals distress migration from poverty, unemployment or environmental stress.
• Gross migration rate (turnover):
  • A high rate means high mobility, typical of economically dynamic or transitional regions. A low rate means a stable population.
  • It does not tell whether the area gains or loses.
• Net migration rate:
  • Positive for net gainers (metropolitan states such as Delhi and Maharashtra); negative for net losers (Bihar, Uttar Pradesh).
  • It is a crude measure: it ignores the age, sex and skill of migrants, so two areas with the same net rate can be affected very differently.
• Migration effectiveness (ME):
  • It ranges from −100 to +100.
  • ±100 means a one-way flow (only in- or only out-migration), the most effective redistribution.
  • Near 0 means large flows that cancel out, as with circular or exchange migration between similar places.
  • It separates circulation from permanent redistribution.
• Migration ratio: in-migrants per out-migrant.
• Immigration and emigration rates apply the same logic to international moves. They are used in policy planning and in population projections.
• Age- and sex-specific migration rates show selectivity. Rates usually peak at ages 20–29, with a smaller peak among children moving with parents, and sometimes a retirement peak.

• The table uses inter-state migrants by last residence who moved in 2001–11, per 1,000 population of 2011 (Census 2011).
  • Bihar’s effectiveness of −81 means its exchange with other states is almost entirely one-way: for every person who came in, about nine left.
  • Maharashtra and Gujarat gain about three in-migrants for each out-migrant.
  • Kerala loses on balance to other states, but its larger flows go abroad, which these inter-state rates do not show.

Spatial and Structural Measures

• Origin–destination (O–D) matrix: a table of flows between every pair of regions. It is the basis of stream analysis, of gravity models and of maps of migration corridors.
• Migration field: the area from which a place draws most of its migrants. Delhi’s field covers the Ganga plain, Haryana and Rajasthan; the Gulf’s covers Kerala, the Ganga plain and Telangana.
• Distance measures: the mean or median distance moved, and the share of moves within the district, within the state and across states. These test distance decay.
• Stream composition: the shares of rural–rural, rural–urban, urban–urban and urban–rural moves, and of each reason for moving.
• Selectivity measures: the age–sex structure of migrants, the sex ratio of migrants, and their education and occupation compared with the population at origin and destination.
• Intensity indices: the crude migration intensity (all moves in a period as a share of the population) allows countries with different boundary systems to be compared.

Indirect Measures

• Used where direct migration data are lacking, as for many countries and for small areas between censuses.
• Vital statistics (residual) method:
  • Net migration = (P2 − P1) − (B − D), where P1 and P2 are the populations at two censuses and B and D the births and deaths between them, that is, total population change minus natural increase (births minus deaths) over the period.
  • Its accuracy depends on complete registration of births and deaths and on comparable census counts.
• Survival ratio methods:
  • The census survival ratio or life-table survival ratio estimates how many people of each age group should survive from one census to the next.
  • The difference between expected and enumerated survivors gives net migration by age.
• Place-of-birth tables of two censuses can be compared to estimate lifetime net migration between regions.

Trends and Patterns of Migration

World

• Long history:
  • Migration is as old as humanity. Homo sapiens dispersed out of Africa from roughly 60,000 years ago.
  • Large historical movements followed: European settler migration, the Atlantic slave trade and Asian indentured labour.
  • The Great Atlantic migration of the 19th century took tens of millions of Europeans to the Americas. The 1840s saw mass flight from Ireland (the potato famine) and Germany.
• Drivers of change: environment (climate, physiography, food supply) and human factors (war, slavery, persecution, political upheaval, economic opportunity).
• Growth of the stock:
  • International migrants rose from 154 million in 1990 to 304 million in 2024.
  • Their share rose only from 2.9% to 3.7%: international migration grows roughly in step with world population.
• South–North and South–South:
  • Europe (94 million) and Northern America (61 million) hold half of all migrants.
  • Much migration is regional: 45% of migrants live in their region of origin.
  • Central and Southern Asia sends most of its emigrants out of the region, chiefly to the Gulf.
• Net gainers and losers, 2015–2024 (UN World Population Prospects 2024):
  • Largest gains: the USA (about 14 million), Germany, Canada and the UK (3–5 million each), Russia, Syria (returns), Colombia (Venezuelan arrivals), South Africa, Spain and Japan.
  • Largest losses: Pakistan (about 14 million), Bangladesh (8.5 million), India (5.8 million), Ukraine and Venezuela (about 5 million each), China, Nepal and the Philippines.
  • Two kinds of loss stand out:
    • labour-driven, temporary and economic, from Bangladesh, Nepal, the Philippines and India;
    • conflict-driven, from Ukraine, Venezuela, Afghanistan and Syria.
• Migration as the driver of population change in developed countries:
  • In many high-income countries, deaths now exceed or approach births. Net immigration is the main or only source of growth.
  • Immigration is projected to be the main driver of population growth in 52 countries and areas through 2054, including Australia, Canada, Qatar, Saudi Arabia and the USA (UN World Population Prospects 2024).
  • In Germany, Italy, Japan and Russia, population peaked earlier than it would have without immigration.
  • Immigration slows ageing but cannot reverse it: migrants also age, and their fertility converges towards native levels.
• Other features:
  • Feminisation: women are about 48% of international migrants, and more women now migrate independently for work.
  • Skill differentiation: low-skilled labour migration and high-skilled knowledge migration coexist.
  • Forced migration has grown to 117.8 million displaced people (end-2025).
  • Temporary and circular migration is rising.

India

• Historical:
  • Emigration began on a large scale with indentured labour after Britain abolished slavery in 1833. Indians went to Mauritius, Fiji, the Caribbean, Natal and Malaya.
  • The Partition of 1947 caused one of the largest mass migrations in history.
• Internal migration trend (Census, by last residence):
  • 231 million migrants in 1991.
  • 314 million (30.6%) in 2001.
  • 456 million (37.6%) in 2011.
• Recent estimates:
  • PLFS 2020–21: migration rate 28.9% (rural 26.5%, urban 34.9%).
    • Women migrate far more than men (about 48% of women in both rural and urban areas).
    • 86.8% of female migrants moved for marriage.
    • Men moved mainly for employment: 22.8% in search of work, 20.1% to take up work.
  • The 2024 EAC-PM study estimated about 40 crore migrants in 2023 (28.9%). It suggested that migration has slowed as roads, housing, electricity and jobs have improved at the origins.
• Patterns:
  • Short-distance: 61% of 2011 migrants moved within the district; only 11.9% crossed a state boundary.
  • Female-dominated, because of patrilocal marriage.
  • Rural–rural is the largest stream; urban–urban grew fastest in 2001–11.
    • Among migrants whose origin is classified, rural–rural moves fell from about 64% in 1991 to about 54% in 2011.
    • Urban–urban moves more than doubled in 2001–11, helped by the creation of some 2,500 new census towns.
  • Inter-state migration is a small but rising share. Inter-state migrants who moved in 2001–11 numbered about 2.2 crore, up from 1.7 crore in the previous decade.
  • Recent movers are more male and more work-driven than the stock as a whole: the share moving for work rises sharply with distance, to nearly half of male inter-state migrants.
• International:
  • India is the largest country of origin (18.5 million emigrants in 2024) and the largest recipient of remittances (US$ 137.7 billion in 2024).
  • Gulf countries draw semi-skilled and unskilled workers from Kerala, Uttar Pradesh, Bihar, Tamil Nadu and Telangana. Western countries draw professionals, students and nurses.
  • North India (Uttar Pradesh, Bihar) sends mainly semi-skilled and unskilled labour to the Gulf. South India (Kerala, Tamil Nadu) sends a higher share of skilled and educated migrants, including health workers.
  • India is also a destination: about 4.8 million immigrants (2024), mostly from Bangladesh, Nepal and Pakistan.
• Indian migration combines push factors (unemployment, poverty, population pressure) with pull factors (higher wages, global opportunities). Skilled brain drain and brain circulation coexist with continuing low-skilled labour migration.