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POPULATION AND HEALTH : TECHNIQUES OF ANALYSIS AND

POLICY PERSPECTIVE

MIGRATION CONCEPTS AND TECHNIQUES OF ANALYSIS

MA (SDP), 2nd Semester, 2012

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

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)

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

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

CONTINUED…

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 migrationII. Rural to Urban migrationIII. Urban to Rural migrationIV. 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.

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’

TYPES OF MIGRATION

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

CENSUS-INDIA, 2011, HOUSEHOLD SCHEDULE B

POPULATION AND HOUSING CENSUS- BHUTAN 2005

DETERMINANTS AND CONSEQUENCES OF INTERNAL MIGRATION

Determinants:i) Development/Underdevelopment and Migrationii)Spatial disorganization and Internal Migration

Consequences: 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

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

MEASURES IN MIGRATION Measurement and analysis of migration for

population estimates and projections-I) Estimation of lifetime from place of birth data

1) Out-migration from A, x1= A12+A13+A14

2) In-migration to A, y1: A21+A31+A41

3) Non-migration for A: A11

4) Therefore, net-migration for A = (y1-x1)

Place of Birth

Place of Enumeration

A B C D

ABCD

A11

A21

A31

a41

A12

A22

A32

A42

A13

A23

A33

A43

A14

A24

A34

A44

II) Estimation of Inter-censal Migration from place of birth dataEstimated by subtracting the survival of migrants counted in the first census from the migrants counted in the second census

Indirect 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 will survive during the inter-censal period.

CALCULATING OF SURVIVAL RATIO Pn+, t+n

S = Pt

Where, Pn+, t+n= population aged n and above at time t+n

n = interval between the two censuses

Or, from life-table available for intercensal period, Tn

S =To

where, Tn and To are stationary population above age n and o respectively.

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 1.3.2001

Period of in-migration

Less than one year

1 to 5 years6 to 10 years11 years and above

1.3.2000 to 1.3.2001

1.3.1996 to 1.3.20001.3.91 to 1.3.1996before 1.3.1991

IV) Estimation of Migration from Place of Residence at a Fixed Prior Date Data

Place of

Origin Recent migration stream 1986 - 91

Life-time migration stream 1991

  To place P

From place P

Net Balance

To place P

From place P

Net Balance

A1

A2

A3

A4

A5

I1

I2I3I4I5

O1

O2

O3

O4

O5

+ N1

+ N2

+ N3

- N4

- N5

I11

I21

I31

I41

I51

O11

O21

O31

O41

O51

- N11

+ N21

- N31

+ N41

- N51

  I O + N I1 O1 + N1

Life-time and Current Migration Streams to and from Place P

INDIRECT MEASURES:

I) National Growth Rate method:

Where, Pt, Pt+n denotes the national population at time t

and t+n. Pt

i, Pit+n denotes the population of area i at time t

and t+n.

Assumptions,

1) Pop-growth is equal everywhere

2) Closed to international migration

100 P

P-P - P

P-P = mt

tn+t

it

it

in+t

i

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 areaB and D are the number of births and deaths occurred to the residents of the area in intercensal period

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 population

Net migration among survivors of persons aged x for area i:

 

Px+n, t+n

Net Mi (x) = Pi, x+n, t+n - Pi, x, t

Px, t

where,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 age group.

REFERENCES:

Methods and Materials, Chapter 19 and Chapter 18

DPS Migration Module, IIPS