Session 9 migration techniques


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Session 9 migration techniques

  2. 2. INTRODUCTION Uneven distribution of human population in space- undergoes changes over time Modern times- uneven distribution disproportionately higher for urban areas Migration is the third basic factor affecting change inthe population of an area Important element in growth of labour-force Demography of migrants and non-migrants- its importance in socio-economic, development aspects
  3. 3. KEY CONCEPTS IN MIGRATION STUDIES Migration is a form of geographic or spatial mobility involving a change of usual residence between clearly defined geographic units. It involves two areas, place of origin and place of destination.  Two specific lacuna in the definition, i.e, excludes-  Short-term or cyclical or Circulatory or temporary movements  non-comparability overtime due to change of boundary Migrant: person who has changed his usual place of residence from one migration-defining area to another at least once during the migration interval (usually, interval may be one year, five years, or ten years, or inter-censal period)
  4. 4. CONTINUED… Migration Interval:  Fixed-term or period migration: The interval may be definite, e.g. one year, five years, ten years, the inter-censal period.  Life-time: or indefinite i.e.,- life-time migrant Place of Origin: starting point of ‘migration’ i.e.,  a) an area of residence at the beginning of migration interval, or,  b) an area of residence from which last move was made for the current migration interval Place of Destination: terminal point of ‘migration’, at end of the migration interval
  5. 5. CONTINUED… In-migration: ‘move’ in respect to place of destination. International move- Immigrant, within country- In-migrant Out-migration: ‘move’ in respect to place of origin. International move- Emigrant, within country- Out-migrant Gross Migration: data referring all migration (in/out) in respect to specific origin/destination, over a specific interval Net Migration: data referring to only ‘balance’ of movement in opposite directions, in respect to specific origin/destination, over a specific interval Migration Stream: group of people moving during a given migration interval that have a common area of origin and of destination Lifetime Migration: A person whose place of residence at census/survey date is different from his place of birth is a lifetime migrant
  6. 6. TYPES OF MIGRATION International migration- takes place across international boundary. Refers to socio-economic and political conditions, especially immigration and emigration laws and policies Internal Migration- occurs within a country. Refers to socio- economic spatial situations within a country. Further grouped into; I. Rural to Rural migration II. Rural to Urban migration III. Urban to Rural migration IV. Urban to Urban migration R-U: most important. Contributes to transfer of labour force from the traditional agricultural sector to the urbanised industrial sector Each of these migration streams has different premises, causes and consequences.
  7. 7. TYPES OF MIGRATION Migration Stream may be further categorized into-  Intra-district migration  Inter-district migration  Inter-State migration  International migration Categories based on reasons for migration:  Marriage migration;  Labour migration or migration of people for work, employment, etc.;  Migration for prosperity;  Refugee migration arising due to political or other reasons  Migration due to natural calamities;  Return migration; and  Brain-drain, migration of professionals from developing to developed countries. ‘Single migration’ & ‘Family migration’
  8. 8. SOURCES OF DATA- MIGRATION Analyzing changes in pop-structure and labor force of an area: number and characteristics of persons entering or leaving an area is required, together with census data on population size and vital statistics. Three most vital sources of migration data-  Censuses  Surveys  Population Registers Basic migration data and their characteristics  Place of birth data: difficulties in collection and interpretation, i.e., return migrants  Place of last residence: Data on the place of last residence also suffer from absence of a definite time reference  Duration of residence: return migrants and provides the timing of last move
  10. 10. DETERMINANTS AND CONSEQUENCES OF INTERNALMIGRATIONDeterminants:i) Development/Underdevelopment and Migrationii)Spatial disorganization and Internal MigrationConsequences: Consequences on Rural Areas  Effect on rural incomes and its distribution  Effect on rural capital formation and technological change  Effect on modes of rural production  Effect on rural fertility
  11. 11.  Consequence on urban areas:  Effect on wages and unemployment  Effect on labour force participation  Effect on availability of urban amenities  Effect on urban income distribution  Effect on urban development  Effect on demographic structure of urban population
  12. 12. MEASURES IN MIGRATION Measurement and analysis of migration for population estimates and projections-I) Estimation of lifetime from place of birth data Place of Birth Place of Enumeration A B C D A A11 A12 A13 A14 B A21 A22 A23 A24 C A31 A32 A33 A34 D a41 A42 A43 A441) Out-migration from A, x1= A12+A13+A142) In-migration to A, y1: A21+A31+A413) Non-migration for A: A114) Therefore, net-migration for A = (y1-x1)
  13. 13. II) Estimation of Inter-censal Migration from place of birthdataEstimated by subtracting the survival of migrants counted in the first censusfrom the migrants counted in the second censusIndirect estimate of inter-censal net-migration:NM = (It+n - Ot+n) - (SIIt - So Ot)Where It - number of lifetime in-migrants at time t in a particular area, It+n - number of lifetime in-migrants at time t+n in that particular area, Ot - number of lifetime out-migrants at time t from that particular area, Ot+n - number of lifetime out-migrants at time t+n from that particular area, NM - net inter-censal migration.SI and SO are intercensal survival ratios indicating what proportions of It and Ot that willsurvive during the inter-censal period.
  14. 14. CALCULATING OF SURVIVAL RATIO Pn+, t+n S = PtWhere,Pn+, t+n= population aged n and above at time t+nn = interval between the two censusesOr, from life-table available for intercensal period, Tn S = Towhere, Tn and To are stationary population above age nand o respectively.
  15. 15. III) Estimation from Duration of Residence Data Question asked: How long have you been living in this place? In-migration can be decided as follows: Duration of residence as on Period of in-migration 1.3.2001 Less than one year 1.3.2000 to 1.3.2001 1 to 5 years 1.3.1996 to 1.3.2000 6 to 10 years 1.3.91 to 1.3.1996 11 years and above before 1.3.1991
  16. 16. IV) Estimation of Migration from Place of Residence at a Fixed Prior Date DataLife-time and Current Migration Streams to and from Place P Place of Origin Recent migration stream 1986 - 91 Life-time migration stream 1991 To place From place P Net To place P From place Net P Balance P Balance A1 I1 O1 + N1 I11 O11 - N11 A2 I2 O2 + N2 I21 O21 + N21 A3 I3 O3 + N3 I31 O31 - N31 A4 I4 O4 - N4 I41 O41 + N41 A5 I5 O5 - N5 I51 O51 - N51 I O +N I1 O1 + N1
  17. 17. INDIRECT MEASURES:I) National Growth Rate method: i i Pt + n - Pt - Pt + n - Pt mi = i 100 Pt PtWhere, Pt, Pt+n denotes the national population at time t and t+n. Pti, Pit+n denotes the population of area i at time t and t+n.Assumptions,1) Pop-growth is equal everywhere2) Closed to international migration
  18. 18. II) Vital Statistics Method (Residual Method)Net intercensal migration = (Pt+n - Pt) - (B - D)Where, Pt, Pt+n are the total population at two successive censuses of the area B and D are the number of births and deaths occurred to the residents of the area in intercensal period
  19. 19. III) Census Survival Ratio Method (CSR Method): Is the ratio of the population aged x+n at a given census to the population aged x at the earlier census taken n years earlier CSRs are computed for a nation as a whole for a closed populationNet migration among survivors of persons aged x for area i: Px+n, t+nNet Mi (x) = Pi, x+n, t+n - Pi, x, t Px, twhere, Pi, x, t = Population in the ith area in a particular age group x at the first census (time t) Pi, x+n, t+n = Corresponding population in the ith area n years older at the second census (time t+ n). Px, t and Px+n, t+n = Corresponding population of the country as a whole in the two successive censuses (time t and t+n respectively).Net Mi (x) = Estimate of net migration in the ith area in a particular agegroup.
  20. 20. REFERENCES: Methods and Materials, Chapter 19 and Chapter 18 DPS Migration Module, IIPS