15 Migration, Basic Concepts, Measurements and Consequences

Atreyo Mondal and Gautam Kshatriya

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Contents

    1.       Introduction

2.       General Terms and Concepts of Migration

  • Internal Migration
  • International Migration
  • Immigration and Emigration
  • In-migration and Out-migration
  • Migratory Movement
  • Place of Origin/ Place of Departure and Place of Destination/ Pace of Arrival
  • Gross and Net Migration
  • Migration Streams

3.  Source of Data for Migration

  • Census
  • Surveys
  • Population Register

4. Methods of Measuring Internal Migration

4.1. Direct Techniques

  • Migrants or Lifetime Migrants
  • Non-migrants

    4.2. Indirect Techniques

  • Using Vital Statistics Method
  • The use of Estimates of the Probability of Survival

5.  Internal Migration in India

6.  Theories of Migration

6.1. Everett Lee in his A Theory of Migration

6.1.1. Factors Associated with the Area of Origin

6.1.2. Factors Associated with the Area of Destination

6.1.3. Intervening Obstacles

6.1.4. Personal Factors

6.2. Duncan’s Theory

6.2.1. Economic and Technical Cause

6.2. 2. Social Causes

6.2.3. Personal Causes

6.2.4. Natural Causes

6.2.5. Other Causes

7.    Consequences of Migration

7. 1. Positive Effects

7.2. Negative Effects

8. Summary

    Learning Objectives

  • To know about the To know about general terms and concepts of migration
  • To know about the source of data for migration
  • To know about the methods of measuring internal migration
  • To know about different theories of migration

    1. Introduction

 

According to the “Recommendations on Statistics of International Migration” by the United Nations Statistics Division (1998), long-term migrants are persons who move to a country other than that of their usual residence for a period of at least one year, so that the country of destination effectively becomes their new country of usual residence. Short-term migrants are persons who move to a country other than that of their usual residence for a period of at least three months but less than one year except in cases where the movement to that country is for purposes of recreation, holiday, visits to friends and relatives, business, medical treatment, or religious pilgrimage (UN Statistics Division 1998).

 

The duration threshold that identifies migrants varies across countries (Lemaitre, Liebig, and Thoreau 2006). For example, under the United Nations. (UN) definition, international students who study in the receiving country for more than one year would be considered migrants. The International Migration Outlook (OECD 2006) made a first attempt to characterize migrants by “reasons for movement” and to harmonize statistics among Organisation for Economic Co-operation and Development (OECD) countries.

 

The United Nations Multilingual Demographic Dictionary defined migration- “Migration is a form of Geographical mobility or spatial mobility between one geographical unit and another, generally involving a change in residence from the place of origin or place of departure to the place of destination or place of arrival. Such migration is called permanent migration and should be distinguished from other forms of movement which do not involve a permanent change of residence”.

 

Migratory movements are therefore a product of social, cultural, economic, political and/physical circumstances in which individuals and societies find themselves. “It is thus”. a response of human organisations to economic, social and demographic forces in the environment.(Bogue., 1969).

 

Nomadic movements are normally not regarded as migrations as there is no intention to settle in the new place and because the movement is generally seasonal. Only a few nomadic people have retained this form of lifestyle in modern times. Also, the temporary movement of people for the purpose of travel, tourism, pilgrimages, or the commute is not regarded as migration, in the absence of an intention to live and settle in the visited places.

Source: http://kids.britannica.com/kids/article/Human-Migration/353465

   More than 215 million people, or 3 percent of the world population, live outside their countries of birth. Current migration flows, relative to population, are weaker than those of the last decades of the nineteenth century.

 

The top migrant destination country is the United States, followed by the Russian Federation, Germany, Saudi Arabia, and Canada. The top immigration countries, relative to population, are Qatar (87 percent), Monaco (72 percent), the United Arab Emirates (70 percent), Kuwait (69 percent), and Andorra (64 percent).

 

The United States has seen the largest inflows of migrants between 2005 and 2010. There was a surge of migrant flows to Spain, Italy, and the United Kingdom, mainly from Eastern Europe as well as Latin America and North Africa. The six Gulf Cooperation Council countries (Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and the United Arab Emirates) have also seen a significant increase in migrant flows in the past few years, mostly from South Asia and East Asia. However, new migration flows in all regions have weakened because of the global financial crisis.

 

The volume of South–South migration (migration between developing countries) is larger than migration from the South to high-income countries belonging to the Organisation for Economic Co-operation and Development (OECD). High-income non-OECD countries such as the Gulf countries are also major destinations 6 for migrants from the South. South–South migration is significantly larger than migration Highlights x Highlights from the South to high-income OECD countries in Sub-Saharan Africa (73 percent) and Europe and Central Asia (61 percent) (Migration and Remittance Factbook. 2011).

 

Migration is the third component of population change, the other two being mortality and fertility. The nature of migration as a factor affecting population size is different from that of mortality and fertility. Migration is not a biological variable, while both mortality and fertility operate within the biological framework, though social, cultural, economic and political factors do exercise some influence on it. Migration is entirely determined by the wishes of the persons involved, though in exceptional cases this may not true. Usually, each migratory movement is deliberately made an element of human volition is involved in the decision to move. Terms such as death disease births abortion etc are easily understood by the public for scientific and commonly understood meanings of these terms do not differ much from each other. On the other hand terms such as change of place, migration communication, mobility emigration, immigration, immigration, out migration may connote different meanings to different persons, for their meanings in scientific language and common parlance may differ.

 

Migration may be considered as a symptom of basic social change. In most countries it has been observed that industrialisation and economic development have been accompanied by large scale movements of people from areas of town, from towns to towns to other towns, and from one country to the other.

 

Countries like Asia, Africa, Latin America, which are at present undergoing technological changes are experiencing some type of migration from rural to urban areas, and these streams of migration have given rise to metropolitan cities. In case of India the side effects of unprecedented population growth as well as industrialisation and economic development is a rapid increase in internal migratory movements. The emergence of such a massive population phenomenon especially that of rural-urban migration has attracted the attention of planners and policy-makers to the problems arising out of migration.

 

Sociologists and social psychologists study migration because they are interested in studying the social and psychological problems associated with it, specially those concerning migrants, the people who live in areas from which these migrants come (sending areas) and those who live in areas where migrants arrive (receiving areas). Data on the age sex, mother tongue, education and occupation of the migrants are useful to sociologists and social psychologist, for these data enable them to plan programmes in order to solve or control the problems arising out of migration which are social and psychological in nature. (Bhende.,& Kanitkar. 2000).

 

2. General Terms and Concepts of Migration

 

The collection and analysis of migration data are carried out on the basic of a standard set of definitions of concepts.

 

Migration study resolves around

 

1. Internal migration

Internal migration is the migration of persons within a country

 

2. International migration

International migration refers to the movement of people from one country to other.

 

3. Immigration and Emigration

The terms immigration and emigration refer respectively to movement into or out of a particular territory, and are used only in connection with the international migration.

 

4. In-migration and Out-migration

In- migration is movement into particular area while Out-migration is movement out of particular area. In these cases the movement takes place internally within a country.

 

5. Migratory movement

The term is used in case when a section of population movement occurs due to migration process.

 

6. Place of Origin/ Place of Departure and Place of Destination/ Pace of Arrival

The place from where a move is made is the place of origin or departure. The place of arrival or the place of destination refers to the place at which the movement terminates.

 

7.  Gross and net migration

The total of the arrivals of the immigrants and in-migrants and departures of emigrants and out-migrants is known as gross migration or the volume of migration. Net migration is the difference between the total number of persons who arrive and the total number of persons who leave. This is also referred to as the balance of migration.

 

8. Migration streams

The total number of moves made during a given migration interval which have a common area of origin and a common area of destination.

 

3. Source of Data for Migration

 

9. Census

 

The most important source of data on migration in most countries is the national census. These data may be obtained through the census directly by asking questions on migration or may be estimated indirectly. The usual direct questions on internal migration cover the following items: place of birth, place of last residence, duration of residence in the place of enumeration, and place of residence on a specified data before the census. Of the various questions asked to obtain direct information on migration, the question on the place of birth is most widely asked. In India, up to 1961, census data on migration were obtained through particulars of the birth place. In 1971, however an additional question was asked to obtain information on migration and this question concerned the place of last usual residence. In 1981 census, in additional to the pervious questions, information also obtained about the reasons for migration from place of last residence and duration of residence at the place of enumeration. Information on migration was collected on a sample basis.

 

10. Surveys

 

Direct information on internal migration are also be obtained from sample surveys, which are useful in supplementing the information obtained from a national census. Such surveys provide information on the characteristics of the migrants, their motives of migration, their attitudes towards migration, etc. such data are useful in studying the question of internal migration in dept.

 

11.   Population Register

 

In some countries, information on internal moves involving residential changes is constantly recorded in the continuous population registers. Data available from such population register are useful for an analysis of interval between each interval migration. Such population registers are available in Korea, Taiwan, Sweden, etc.

 

4. Methods of Measuring Internal Migration

Generally for estimation of internal migration is done by following processes –

 

4.1. Direct Techniques

 

This process is based on the data obtained from asking direct questions which are asked during a census on the movements of person.

 

Questions like- The place of birth of the person, the last previous place of residence of the person, the duration of stay of a person at the present place of residence.

 

On the basis of question – “The place of birth of the person” the information can classify the population on two groups-

 

12.   Migrants or lifetime migrants

Mainly those who have enumerated in a place which is different from the place where they were born.

  • Non-migrants

    Those who have enumerated in the place where they are born.

 

There are several advantages as well as disadvantages of using information of the place of birth to measure lifetime internal migration. The question on place of birth is easily understandable, simple and is expected that a person would remember his/her place of birth and thus the information from this question is accurate and complete.

 

But in some cases inaccuracy creeps in because of boundary changes in political regions of which the respondent becomes unaware and in some social practises introduces artificial biases in the information on the place of birth.

 

In India, girls usually go to parents home for their first delivery. The child born at the home at the home of mother’s parents by definition becomes a lifetime migrant, although being a non migrant. It has therefore been suggested that for a proper analysis of migration information, the usual place of residence of the parents should be taken as the place of birth of such a child rather than the place where the birth actually occurred.

 

It is therefore be concluded that though it is comparatively easy to collect information on the birth place of persons and to estimate the volume of lifetime migration on the basic of such data, there are many limitations for this approach.

 

On the basis of question –“Duration of Residence” the information obtained through this question forms another approach to the study of migration. Persons who have lived in the place of enumeration all their lives are treated as non migrants. The following categories are included as migrants on the basis of their duration of residence at the place of enumeration, and these include “all who have ever migrated: i) Those born outside the area of enumeration ii) Those born in the area of enumeration who had at sometime lived outside it (return migrants).

 

The duration of residence approach fills a serious gap in the place of birth approach; it is customary in many countries to differentiate migrants from non migrants on the basic of birth statistics. The most important aspect of the data on duration of residence is the information of the timing of the last move of lifetime migrants. In this approach the time or the year of the move is a differentiating variable in contrast to the distance or the political boundary used in the place of birth approach.

 

In many countries it is customary to differentiate migrants from non migrants on the basic of place of birth statistics and then classify the migrants (defined on the basic of the place of birth data) according to the duration of residence in the place of enumeration. Such type of analysis is helpful in the study of migration.

 

There is however problems associated with the accuracy of the data on duration of residence. The person, usually the head of the household, who gives the information, may not know exactly the duration of residence of each person in the household.

 

It has been observed that the percentages of those for whom information on duration o residence is not available are higher for females than for males.

 

On the basis of question – “Place of last residence” data may be used to measure migration in exactly the same way as data on the place of birth are used. The data on the last residence are cross-classified with the data on enumeration with a view to obtaining the volume of in migration, out migration and net migration between the place of origin and place of destination. The data on last place of residence are more useful for analysis of migration, when cross-classified with the data on duration of residence.

 

The advantage of the data on the place of residence in the study of migration is that it reflects a direct movement from the place of origin to the place of destination.

 

On the basis of question – “Place of residence at a fixed prior date” some countries a specified date is included in the census questionnaire. Any measurement of migration on the basic of residence at a fixed prior date is simple and specific. Thus it is considered by many demographers to be more satisfactory and useful measure for migration analysis than measure based on place of birth data or last residence data. The drawback for this approach when creeping of inaccuracy happens due to recall lapse.

 

4.2. Indirect Techniques

 

This technique of estimation on migration do not require asking questions, the final estimation is done through total counts of census and the available age sex distribution of the population.

 

Addition to the measurement of migration based on information obtained through direct techniques, indirect techniques takes account of estimating net intercensal (between two census) migration by using the population counts from two successive census operations.

 

The growth in the population of any area of region is basically due to natural increase of excess of births over deaths and migration movements.

 

Having population counts of an area at two points of time are available and if the number of births and deaths, which had occurred in that area, is also known then it is possible to count tentatively the expected population at the end of interval in absence of any kind of migration. The difference between the observed (actual population count at the end of the period) and the expected population gives the estimate of the net change due to migration.

 

The tools to arrive these estimations are-

  • Using vital statistics method

    Countries where reliable information on the birth and death of inhabitants is available, the estimation of a natural increase between two successive census operations can be obtained. The estimation of net migration can also be done subtracting the natural increase from the total population change.

 

In developing countries the data on births and deaths obtained from vital registration systems re not accurate and adequate, hence are poor quality. The errors in reporting of births and deaths therefore affect the estimation of net migration based on this approach.

  • The use of estimates of the probability of survival

   The approach for estimating the net internal migration for the period between two census operations is based on the survivorship probabilities obtained from existing life tables. The basic information needed is the age distribution of sex as enumerated in each area in two successive census operations and a set of survivorship ratios which may be applied to the population of the first census in order to derive an estimate of the number of persons expected to survive to the second census. The differences between the enumerated populations give the estimation of net internal migration.

 

5. Internal Migration in India

 

For a large country like India, the study of movement of population in different parts of the country helps in understanding the dynamics of the society better. At this junction in the economic development, in the country, especially when many states are undergoing faster economic development, particularly in areas, such as, manufacturing, information technology or service sectors, data migration profile of population has become more important.

 

The main source of the study of internal migration in India is provided by the decennial population census. In each census since 1881, a question has been asked from each person about his/her place of birth. The reply to this question provides the basic for an analysis of internal migration in India. In 1961’1971’1981 census operations, the scope of enquiry was widened. In the 1961 census, in addition to collecting information on the place of birth with reference to rural-urban residence, information on the duration of residence at the place of enumeration was also collected. In 1971, a question on the place of last residence was asked in addition to the question on the place of birth with reference to rural-urban residence. Information regarding District and State of the birth of place was also collected in 1971 census. In 1981 the question on migration were further expanded to elicit reasons for migration.

 

In India, as per census 2001, about 307 million person have been reported as migration by place of birth. Out of them about 259 million (84.2%), migrated from on part of the state to another, i.e., from one village or town to another village or town. 42 million (2%) from out side the country. The data on migration by last residence in India as per Census 2001 shows that the total number of migrants has been 314 million. Out of these migrants by last residence, 268 million (85%) has been intra-state migrants, those who migrated from one are of the state to another. 41 million (13%) were interstate migrants and 5.1 million (1.6%) migrated from out side of the country.

 

TABLE 1: NUMBER OF MIGRANTS BY PLACE OF BIRTH – INDIA 2001

 

TABLE :2 NUMBER OF MIGRANTS BY PLACE OF LAST RESIDENCE – INDIA 2001

 

Opportunities in urban areas for employment, education, etc have been a pull factor attracting migrants from rural to urban areas and from smaller towns and cities to larger urban areas. There is also migration in the opposite direction from urban to rural areas due to various reasons.

 

The migration during the last decade, i.e., migrants with duration of residence of 0-9 years at the place of enumeration, by various migration streams are summarized in the following table:

 

TABLE 3: NUMBER OF INTRA-STATE AND INTER-STATE MIGRANTS IN THE COUNTRY (DURATION OF RESIDENCE 0-9 YEARS) BY RURAL URBAN STATUS – INDIA 2001BY RURAL URBAN STATUS – INDIA 2001

   Out of about 98 million, total intra-state and inter-state migrants in the country during last decade, 61 million have moved to rural areas and 36 million to urban areas. Migration stream out of rural areas(73 million) to another rural areas was quite high (53million) in comparison to from rural to urban areas (20 million). About 6 million migrants went to rural areas from urban areas. On the basis of net migrants by last residence during the past decade, i.e., the difference between in – migration and out – migration, in each state, Maharastra stands at the top of the list with 2.3 million net migrants, followed by Delhi (1.7 million), Gujrat (0.68 million) and Haryana (0.67 million) as per census. Uttar Pradesh (-2.6 million) and Bihar (-1.7 million) were the two states with largest number of net migrants migrating out of the state. There are various reasons for migration as per information collected in Census 2001 for migration by last residence. Most of the female migrants have cited ‘Marriage’ as the reason for migration, especially when the migration is within the state. For males, the major reasons for migration are ‘work/employment’ and ‘education’.

 

TABLE 4: REASONS FOR MIGRATION OF MIGRANTS BY LAST RESIDENCE WITH DURATION (0-9 YEARS) INDIA 2001

 

6. Theories of Migration

 

Generalization about selectivity in migration is universally not true, except for age selectivity; the study of motivational factors of migration becomes even more complex than the study of the behavioural and psychological aspects of the other two factors of population change, namely, fertility and mortality. Hence our present theoretical and empirical knowledge of the phenomenon of migration is only very elementary. Many researches in migration are empirically oriented and contain only a factual description of migration streams and flows or at the most deal with the characteristics of migrants. Due to deficiencies of migration data and the problems inherited in them, demographers have devoted their attention mainly to methodological problems of the measurement of internal migration. This explains why a majority of studies on internal migration lack generalization or at least attempt to build theories of the phenomenon of migration.

 

Those who have tried to generalise about migration phenomenon, or have attempted to study the factors affecting internal migration movements, have adopted two distinctly different approaches. The first approach is mainly situation oriented in terms of push and pull factors, in the sense that it attempts to study the conditions and situation outside that attract persons on the other. The second approach attempts to formulate empirical generalisations and describes patterns to formulate empirical generalisations and describes patterns of migration, preferably in the form of mathematical models which are valid as universal laws.

 

6.1. Everett Lee in his A Theory of Migration

The factors that determine the decision to migrate and the process of migration into four categories:

 

6.1.1. Factors associated with the Area of Origin

Here are many factors which motivate people to leave their place of origin to outside area. They are push factors.

 

6.1.2. Factors associated with the Area of Destination

There are very attractive forces at the area of destination to which the proportion of “selectivity” migrants is high. According to Lee, such forces are found in metropolitan areas of a country. Pull factors are present in such areas.

 

6.1. 3. Intervening Obstacles

There are intervening obstacles like distance and transportation which increase migrant selectivity of the area of destination. These obstacles have been lessened in modern times with technological advances. Lee also refers to cost of movements, ethnic barriers and personal factors as intervening obstacles.

 

6.1.4. Personal Factors

Lastly, it is the personal factors on which the decision to migrate from the place of origin to the place of destination depends. In fact, it is an individual’s perception of the ‘pull and push forces’ which influence actual migration. He categorises these forces into “pluses” and “minuses” respectively. In other words, pluses are pull factors and minuses are push factors. In between them are “zeros” which balance the competing forces.

 

These are explained in Fig. 1, where the first circle represents the area of origin and the second circle the area of destination. The sign plus represents the forces that attract people to a place (pull factors) and that of minuses represents the forces that push people from the area. Zeros represent the indifference of the people towards migration. In between these forces are the intervening obstacles.

Source- http; // www. sociologydiscussion.com/wp-content/ upload/2016/07/clipimage00-tumb2-1.jpg

 

According to Lee, it is the personal factors such as age, sex, race and education which along with the pull-push factors and intervening obstacles that determine migration. Further, there are sequential migrants such as children and wives of migrants who have little role in the decision to migrate.

 

6.2. Duncan’s Theory

 

O.D. Duncan, in his book, The Theory and Consequences of Mobility of Farm Population, has presented a theory regarding the mobility of population engaged in agriculture. His theory is the combination of microscopic and macroscopic active forces in the process of migration.

 

According to Duncan, whatever effects are created by changes in structural factors of the country, the same effects are caused by migration. Thus, for achieving many structural aims, migration is the functional alternative to social change (http://www.sociologydiscussion.com).

 

Generally, the following factors are responsible for migration

 

6.2.1. Economic and Technical Causes:

 

They relate to the changes occurring in the technique of production, in methods and structure of agricultural operations, in market structure, in price situation, in specialisation, in production, and in relative changes in the wage level, etc.

 

6.2.2. Social Causes:

 

The social causes are development of institutional structure, policies regarding public land and production, development of transport and communication systems, population growth, increase in knowledge and its expansion, class-conflicts and competition, disarrangement coming in social degradation and structure of administration, changing needs of maintenance of family, etc.

 

6.2.3. Personal Causes:

 

In personal causes are included unsatisfied needs, increase in the intelligence of persons and expanding horizon of knowledge, health, emotions of alienations, views regarding neighbours, imagination power, nature, emotions, etc.

 

6.2.4. Natural Causes:

 

The natural causes pertain to environment and atmosphere, frequent existence of diseases, floods, earthquake, droughts, malaria, seasonal changes, land erosion, etc.

 

6.2.5. Other Causes:

 

There are some miscellaneous causes which affect migration. They are labour problems, strikes, riots, increase in real wealth, search of new means or ending up of the supply of old resources, etc.

 

7. Consequences of Migration

 

7. 1. Positive Effects

 

Rural people covert for city goods and as they yearn for them they also try earn for them. Migration favourably alters the values system of the rural communities and the augmented contacts may introduce in the rural societies better awareness towards such things as hygiene, immunization, importance of education of girls, healthy and balanced diet.

 

Migrants from the rural areas are usually in skilled for the jobs in the “Urban formal” sector and hence may pick up sundry jobs in the “urban informal sector”. Such jobs are low paying but also help in warding of hunger, which the migrants would have faced in their original setup. Initially many unskilled migrants take up jobs of mental and manual workers or as petty helpers, assistants or as peddlers of goods. Some migrants may earn good amounts even by such jobs thus the productivity of per capital income and employment increases as mainly migrants move from “zero sum” or even “negative sum” to “positive sum” activities. Thus socio economic productivity goes up.

 

The great advantage lies in the migrants giving better education and training to their second generation.

 

7.2. Negative Effects

 

Negative effects can be experienced in the rural as well as the urban areas. The young persons of rural areas who get education and training in urban areas seldom return to rural areas to improve the next generation of rural people. On the other hand administrative personnel who may be posted in rural may not have the type of commitment needed for developing the rural areas.

 

The urban areas get flooded with surplus labour from the rural areas and the shanty houses can be termed as “graves of over migration” the population of the slum areas degrades the health environment for the poor and the rich alike (Srivastava., 1998).

 

8. Summary

 

Migration is a form of Geographical mobility or spatial mobility between one geographical unit and another, generally involving a change in residence from the place of origin or place of departure to the place of destination or place of arrival.

 

Migratory movements are therefore a product of social, cultural, economic, political and/physical circumstances in which individuals and societies find themselves. “It is thus” a response of human organisations to economic, social and demographic forces in the environment.

 

Nomadic movements are normally not regarded as migrations as there is no intention to settle in the new place and because the movement is generally seasonal. Only a few nomadic people have retained this form of lifestyle in modern times. Also, the temporary movement of people for the purpose of travel, tourism, pilgrimages, or the commute is not regarded as migration, in the absence of an intention to live and settle in the visited places. Such migration is called permanent migration and should be distinguished from other forms of movement which do not involve a permanent change of residence.

 

Migration is the third component of population change, the other two being mortality and fertility. The nature of migration as a factor affecting population size is different from that of mortality and fertility. Migration is not a biological variable, while both mortality and fertility operate within the biological framework, though social, cultural, economic and political factors do exercise some influence on it. Migration is entirely determined by the wishes of the persons involved, though in exceptional cases this may not true.

 

More than 215 million people, or 3 percent of the world population, live outside their countries of birth. Current migration flows, relative to population, are weaker than those of the last decades of the nineteenth century.

you can view video on Migration, Basic Concepts, Measurements and Consequences

 

References

  1. 2001 Census of India
  2. 2011. (2nd Eds). Migration and Remittance. The International Bank for Reconstruction and Development / The World Bank.
  3. Bhende, A., & Kanitkar, T., (2000). Principles of Population Studies. Himalayan Publishing House.
  4. Bogue, J. D., (1961). International Migration,In Philip M. Hauser and Otis Dudley Duncan, The Study of Population,New Delhi: Asia Publishing house,1961.
  5. Bogue, J. D., (1969). Principals of Demography, New York: John wiley and Sonms.
  6. Migration and Remittances Factbook 2011.
  7. Srivastava, S. O., (1998). Demography and Population Studies. Vikas Publishing House.
  8. United Nations, Mannual VI, Methods of Measuring Internal Migration.
  9. http://www.sociologydiscussion.com/demography/migration-demography/top-3-theories-of-migration/3148

    Suggested Readings

  1. Survey of Research in Demography by P.B. Desai.
  2. An Introduction to Population by O.W Kenneth and Kammeyer.
  3. Dynamics of Population and Family Welfare in India by Srinivasan and Mukerjee.
  4. Principals of Population Genetics by , A., Bhende and T. Kanitkar.