International Migration: Deﬁnition, Causes and Effects

: This paper explores the concept of migration, and its causes and effects, with a focus on international migration. Various journal articles, reports, and policy documents are reviewed to address the controversies concerning the concept and key issues of migration. The paper indicates that migration is not only a contested concept, but migration research has resulted in different outcomes. It is mainly affected by personal, socio-economic, and political factors associated with the origin and host countries. Similarly, scholars have been asking the question, “who is a migrant?” for decades without a deﬁnite answer. It is also important to consider “what would happen after migrants obtain host country citizenship”: would they continue to be migrants, the host countries’ citizens, or both? This paper contributes to advancing our knowledge and broadening our understanding of the concept of migration and key issues associated with it. It also serves as a base for further discussion.


Introduction
This paper reviews relevant literature on the concept of migration, and its causes and effects, to provide a broad understanding of the concept and key issues associated with it (Hart 1998).Furthermore, the literature review is expected to advance knowledge by facilitating theory development and identifying areas where excessive/little research and/or controversies exist (Hart 1998;Webster and Watson 2002).The current paper is drawn from a bigger research project on the socio-cultural integration of migrants.The basic argument of this paper is that not only is the concept of migration controversial (Skeldon 2017), but it also creates many controversies (Crawley et al. 2008;Skeldon 2017;Spencer 2011).Hence, I searched and read various resources, including journal articles, reports, and policy documents, to develop a thorough understanding of these issues.The following two research questions are used to guide the paper: (1) what is international migration, and (2) what are the causes and effects of international migration?
This paper discusses the concept and key issues of migration, with a focus on international migration.Research indicates that migration is a complex concept with multiple dimensions (Fussell 2012;Skeldon 2017).For instance, the spatial dimension of migration describes the pushes and pulls in origin and destination countries, which will be explained later in this paper (see also Fussell 2012).However, most of the definitions of migration are bounded by time and space (Skeldon 2017).They are not comprehensive enough to include the different types of migration and satisfactorily address the question of "what is a migrant" (Skeldon 2017).Moreover, it is important to note that there is a connection between different types of migration, such as internal and international migration.For instance, the rise in the number of internally displaced people contributes to the increasing number of refugees and asylum seekers, which in turn affects the increasing number of international migrants.Continued conflict has been the main reason for the displacement of people in several countries such as the Democratic Republic of Congo, Ethiopia, Syria, and Myanmar (UNHCR 2018b).It deteriorates the socio-economic and political conditions of countries, affecting the safety of millions of people.This paper discusses the causes of migration in detail.
Another important aspect of migration is its effects.Various studies came with distinct outcomes regarding the effects of migration due to contextual social, economic, and political factors.For example, migration could help the economy of some developing countries by taking the surplus manpower and reducing unemployment (Beine et al. 2001;Bhattarai 2011) and harm others by taking the limited skilled human resources (Appleton et al. 2006;Brown and Lauder 2006;Kellner 1997;Suárez-Orozco 2001).In this paper, I explore the effects of migration by focusing on the individual migrants, and the origin and host countries.

Methodology
This is a review article based on a systematic search and evaluation of reports, policy documents, journal articles, and other publications.Several keywords including "migration", and "refugee" were used to search potential resources on Google, Google Scholar, EBSCOhost, and migration journals and websites (such as the Journal of International Migration and Integration, the International Organization for Migration, and UNHCR).However, not all of the resources I found and read are included in this paper, as I carefully selected my literature review based on the focus of the paper.I followed Hart's (1998Hart's ( , 2018) ) steps for writing a literature review: searching for relevant sources, reading with a purpose, extracting materials on a theme basis, and finally writing up the review.In doing so, I was able to "acquire an understanding of the topic, of what has already been done on it, how it has been researched, and what the key issues are" (Hart 1998, p. 1).Furthermore, through careful literature review and analysis, this paper advances knowledge and scholarship (Webster and Watson 2002).

Understanding Migration: Definition and Types
Migration is an integral part of human history.Human beings have been moving from place to place for social, economic, or political reasons from their earliest days (Koser 2016).Broadly, migration is usually explained in terms of time and space.It is defined as the movement of people that involves a change in usual residence across an administrative boundary such as a village, town, district, or country (Kok 1999).Migration can be in the form of immigration, which is described as the number of people entering a receiving area, or emigration, which refers to the flow of people from a country over a given period of time.Moreover, there are two types of migration: internal, when migrants move within their country; and international migration, a situation in which migrants live outside of their country of birth for at least one year (Poulain and Perrin 2001).Skeldon (2017, p. 2) argued that migration in general, and international migration in particular, is a complicated concept because "its measurement depends entirely upon how it is defined in time and across space".However, the International Organization for Migration (IOM) has provided a better definition of international migration or a "migrant" by avoiding time and territorial limitations.
A migrant is any person who is moving or has moved across an international border or within a State away from his/her habitual place of residence, regardless of (1) the person's legal status; (2) whether the movement is voluntary or involuntary; (3) what the causes for the movement are; or (4) what the length of the stay is (IOM 2019).
The above definition to some extent considers the multifaceted nature of the concept of migration.However, the question is not only related to the length of time individuals should reside or the distance they should travel to be recognised as migrants, but it is also connected to their long-term status after receiving citizenship in their host country.It is important to ask what would happen after they obtain their new citizenship: would they continue to be migrants, the host countries' citizens, or both?In addition, Koser (2016) stated that defining a migrant as "someone living outside their own country for a year or more" does not provide a complete answer to the question "who is a migrant?" for various reasons: First, the concept "migrant" covers a wide range of people in a wide variety of situations.Second, it is very hard to count migrants and to determine how long they have been abroad.Third, just as important as defining when a person becomes a migrant is to define when they stop being a migrant.Finally, it has been suggested that, as a result of globalisation, there are now new "types" of migrants with new characteristics, for example, comprising transnational communities or diaspora (Koser 2016, p. 14).
The term "migrant" comprises a wide range of people, including those who are forced into exile, and this connects to the idea that people migrate voluntarily or involuntarily for socio-economic and political reasons (Bauman 1996;Kempf 2006;Batista-Pinto Wiese 2010).Some people migrate voluntarily-these are referred to as "Tourists" in Bauman's (1996) terms.Nevertheless, many are forced to leave their country due to war, persecution, and extreme economic hardships in their home countries (UNHCR 2018b).The UNHCR (2018b) further stated that such migrants carry out dangerous border crossings and experience extreme displacement and hardship in transit countries.Yet, the world is not hospitable to forced migrants or, in Bauman's terms, the "Vagabonds" (Bauman 1996).They can be victims of xenophobic violence (Misago 2016) and strict immigration control, including detention and even deportation (Kritzman-Amir and Shumacher 2012).
Furthermore, migrants are categorised according to different labels based on the cause and destination of their movement and their legal status in their country of destination.Accordingly, the term "migrant" encompasses displaced people: "individuals who are forced to move against their will" (Shamsuddoha et al. 2012, p. 18).People are also classed as internally or externally displaced depending on whether they crossed their countries' borders or not.Internally displaced people flee their homes, but they remain within their country of origin.They might receive a supply of relief materials such as food, medicines, and other basic facilities, but they are not entitled to refugee status under the UN convention (International Committee of the Red Cross 2010).Refugees often cross international borders due to a lack of protection from their government.The 1951 Geneva Convention highlights the distinctive features of refugees.
A person who is outside his or her country of nationality or habitual residence; has a well-founded fear of being persecuted because of his or her race, religion, nationality, membership of a particular social group, or political opinion; and is unable or unwilling to avail him or herself of the protection of that country, or to return there, for fear of persecution (UNHCR 2011, p. 3).Thus, the broad concept of migration includes refugees, who are externally displaced people, and other individuals who move from one place to another for socio-economic and political reasons.However, it is important to note that not all migrants are refugees.As can be understood from the above definition, refugees face a threat of persecution and lack the protection of their own country.In contrast, non-refugee migrants usually leave their country for employment, family reunification, or study, and enjoy their governments' protection even when they are abroad.Based on the Geneva Convention, many countries have set eligibility criteria for determining the refugee status of individuals.For example, the Home Office (2016) states that individuals must satisfy two requirements to stay in the UK as refugees.First, they must be unable to live safely in any part of their own country due to racial, religious, and political persecution and other human rights violations.Second, they must have failed to obtain protection from their government.Therefore, anyone without one or more of these features is not recognised as a refugee.In such cases, countries recognise these migrants as asylum seekers, pending acceptance or rejection of their international protection.Asylum seekers are individuals who are seeking international protection in other countries but have not yet received any legal recognition or status (Phillips 2011).

Causes of Migration: The Push-Pull Factors
People migrate because of certain factors that push them away from their origin countries or attract them to the host countries.Everett Lee is one of the scholars who contributed to theories of migration and the push-pull model in particular.Despite its original focus on labour or economic migration, the "push-pull" model has been expanded to a different group of migrants, including refugees (James and Mayblin 2016).Lee (1966, p. 50) identified four sets of factors that influence people's decision to migrate: 1.
Factors associated with the area of origin.2.
Factors associated with the area of destination.3.
Personal factors.
Factors associated with the area of origin or push factors trigger migrants to leave their country.As indicated above, conflict and economic insecurity facilitate international migration (Sirkeci 2005;UNHCR 2018b).This suggests that it is not a coincidence that Syrians, Eritreans, and Afghans have been among the top ten nationalities for asylum seekers in the last decade.War and political turmoil in Afghanistan and Syria, and the Ethiopian-Eritrean border war greatly contributed to the exodus of people from these countries (Cummings et al. 2015).Moreover, as Tessema and Ng'oma (2009) noted, deteriorating economic conditions and lack of peace, stability, and good governance are the main factors that cause the migration of individuals from many developing countries.Tessema's and N'goma's points particularly relate to the socio-economic and political development of African states.The majority of the countries are rich in resources, but ordinary people have not benefitted due to conflict, corruption, and bad governance (Mlambo et al. 2019).Thus, many people flee their countries to save their lives as well as improve their economic conditions (Martin and Zürcher 2008;Parkins 2010).
In most cases, migrants, particularly refugees, end up in neighbouring countries (UNHCR 2018b).However, some continue their journey to other countries selected for various reasons such as socio-economic and humanitarian reasons (Kempf 2006;Martin and Zürcher 2008;Parkins 2010; Batista-Pinto Wiese 2010).For example, refugees mainly choose their destination country based on the recognition rate-the probability of being granted asylum in the country (James and Mayblin 2016).Their safety is the primary concern when choosing their destination.Of course, they also consider socio-economic factors such as better job opportunities and wage levels to improve their economic condition and support their family (Docquier and Rapoport 2008).They look for countries where their careers could thrive and their professional work is recognised (Brǎdǎţan and Kulcsár 2014).Hence, many refugees prefer economically developed countries that could grant them asylum and better living standards (Martin and Zürcher 2008;Parkins 2010).However, identifying such destination requires knowledge of the country and possibly of other countries that could serve for comparison.
Technological globalisation, through the internet, television and other networks, has allowed people to learn about the socio-economic and political life of other countries (Adam et al. 1997;Stanojoska and Petrevski 2012).Migrants can access the information they need to identify the advantages and disadvantages of going to a particular country.They also use the information to compare their origin and destination countries.Accordingly, they decide to travel towards a particular place when the evidence in favour of the move is enough to overcome their current situation and other sets of intervening factors (Lee 1966).Nevertheless, it is important to note that not all their information is complete or reliable (Lieber and Weisberg 2002).They just use the information they have to decide where to go because, in most cases, they travel a long, risky and costly journey to reach their destination place (Laub 2016;Tsegay 2022;UNHCR 2018a).Most of them understand that the intervening factors such as distance and cost of the journey could be barriers, but they pay a huge price, in some cases their lives, to make their dream a reality: to escape war, human rights abuse, and economic hardships.Some studies criticise the push-pull model for various reasons (for example, see European Communities 2000; James and Mayblin 2016).According to European Communities (2000, p. 3), the model does not explain "why within regions some people move and others stay".Nonetheless, this is well captured within the push-pull model.The model is not independent because there are personal factors that influence how people respond to push and pull factors (Lee 1966).These factors affect the individuals' decisions to migrate.For instance, as shown above, information about other parts of the world and personal networks are important elements that influence individuals' decisions to migrate or not.In addition, sensitivity or resistance to change is a significant factor as some people migrate for little provocation while others wait until they are forced into exile.
Furthermore, James and Mayblin (2016, p. 6) concluded that the pull elements may not be applicable to certain migrants, particularly "in the case of asylum seekers".However, this conclusion overlooks the "refugees' dreams".Indeed, refugees might not decide upon their destination place at their initial displacement, but they later do so because, like anyone else, they have dreams.As indicated above, they pay a high price to reach their destination and live their dreams.For instance, in 2015, about 153,842 migrants arrived in Italy by sea (International Organization for Migration 2017).Nevertheless, many of them did not stop there.They continued their journey to seek asylum elsewhere.The case of Eritrean arrivals is a clear example.In 2015, out of 36,838 Eritreans who arrived in Italy, only 475 of them applied for asylum, while the rest travelled to and sought asylum in Switzerland, Germany, Netherlands, Sweden, Norway, and the UK (Llanni 2016).In fact, it is important to understand the specific reason why they choose one European country over another.

Effects of Migration
There is an ongoing debate on the effect of migration both at individual and national levels.Some of these scholarly and policy debates are related to migration and development (for example, see Arslan et al. 2014;De Haas 2010, 2011;Docquier and Rapoport 2008;Dustmann et al. 2008).However, issues of national security have affected policy debates on migration, especially since 9/11.Schüller (2016) explained that 9/11 had a negative impact on people's attitudes toward migrants not only in the USA but also in other countries such as Canada and Germany.Many countries established more restrictive immigration policies, while xenophobic violence towards immigrants increased (Castanho Silva 2018).Generally, migration has a significant socio-economic and political effect on migrants, and source and destination countries (Appleton et al. 2006;Vinokur 2006;Zembylas 2012).
As indicated, many migrants travel through long and risky routes which expose them to mistreatment and even death (Laub 2016;Tsegay 2022;UNHCR 2018a).Such situations are prevalent for vagabonds, who often flee their countries to avoid harsh conditions (Bauman 1996).For instance, Eritrean migrants cross many countries' borders to reach their destination, such as Israel and the UK (Laub 2016).In the past decade, many Eritreans suffered and died at the hands of human traffickers and the Mediterranean Sea on route to their destination countries.According to Van Reisen and Rijken (2015), many Eritreans were killed, tortured, and raped by human traffickers in Egypt's Sinai Peninsula.Moreover, the UNHCR reported that thousands of people die or go missing while crossing the Mediterranean Sea (UNHCR 2015, 2018a).For instance, about 13,457 people died or went missing at sea from 2014 to 2017 (UNHCR 2018a).The number of dead and missing people in the Mediterranean Sea also increased due to Italy's moves to prevent rescue ships from picking up migrants offshore Libya (Tondo 2019).Non-governmental organisations (NGOs) were making a big contribution to minimising the death of migrants along the Central Mediterranean Sea route.Nevertheless, "in July 2017, Italy drafted an EU-sponsored code of conduct" aimed at regulating migrant rescuing NGOs operating offshore Libya (Cusumano 2019, p. 106).This took away the little hope and support that migrants had of crossing the Mediterranean safely.In fact, even those who made it safely are often tormented by the harsh experiences they encountered on their journey and suffer from common mental disorders such as posttraumatic stress disorder (PTSD), depression, and anxiety (Hollifield et al. 2018).Moreover, the extreme human rights abuse and risky journey negatively affect their psychological and emotional wellbeing (Boccagni and Baldassar 2015).
However, migration could also be a means of scientific networks and a source of income for many immigrants and source countries (Beine et al. 2011;Tsegay 2021).As discussed above, migrants in general, and refugees, in particular, leave their country in pursuit of a better life.They look for a place that provides them with protection and economic opportunity.Therefore, they use these prospects to develop themselves and support their families who remain in their country of origin.In addition, migrants contribute to the economic growth of their destination countries (Beine et al. 2011;Docquier and Rapoport 2008).They had been a driving force for the economic growth of the USA by adding manpower to the labour force and creating jobs through their small businesses (Ko Chin 2013).For instance, remittance and diaspora tax are the main sources of income for many families and the government in Eritrea, respectively (Kirk 2010;Laub 2016).Similarly, Pettinger (2017) explained that immigration benefited the UK economy by increasing labour force, aggregate demand, and real Gross Domestic Product (GDP) and reducing the dependency ratio.At the same time, migrants can find better-paid jobs and improve their economic condition.Nonetheless, migration takes the limited human resources of many developing countries and deepens patterns of inequality (Appleton et al. 2006;Brown and Lauder 2006;Kellner 1997;Suárez-Orozco 2001).Furthermore, not all immigrants are welcomed and feel at home in their new environment.They may face xenophobic acts and other violations of human rights from the host population (Kritzman-Amir and Shumacher 2012; Misago 2016).
Moreover, migration affects the emotional conditions of migrants and members of the receiving country (Zembylas 2012).Many migrants deal with negative emotions associated with loss, suffering, hardship, and even abuse.Simultaneously, some members of the host country experience fear, anger, and resentment towards migrants who come to their country.It can be argued that both the migrants and members of the receiving country have their reasons for such emotions.For the migrants, it is a strain to integrate into the socio-cultural, economic and political environment of the new country.Moreover, many migrants face enormous socio-emotional difficulties as they emigrate from their country of origin.Studying the emotional suffering related to migration, Crocker (2015) stated that fear and trauma are the two most commonly mentioned experiences related to a border crossing.Crocker (2015) further explained that immigrants identified fear of criminal extortion and kidnapping as heightened anxieties.These situations are highly prevalent for vagabonds who experience human rights violations and other dangers on the route to their destination place.In such a situation, many migrants experience extreme fear and worry, as well as outbursts of strong emotions, nightmares, and other sleep problems (Crocker 2015;UNHCR 2018b).Discourses of competition for jobs (Brown and Lauder 2006) and potential terrorism (Huysmans and Buonfino 2008;Martin and Martin 2004) often circulate among the receiving population.Such phenomena can increase the fear and hatred of the receiving people and sometimes lead to racial and ethnic oppression and violation of the human rights of migrants by the host people (Kempf 2006;Suárez-Orozco 2001;Zembylas 2012).
People's emotions are related to their life trajectories within a particular environment.They are connected to socio-cultural relationships that people make within their social and ethnic boundaries (De Leersnyder et al. 2011).Moreover, Boccagni and Baldassar (2015) stated that the emotional life of migrants is an indication of their socio-cultural interactions and constructions throughout their life trajectories.This suggests that people's emotions might change with a change in life trajectories initiated through different means, including a change in environment.For example, people's emotions change as they migrate from their home countries to other places (Boccagni and Baldassar 2015).In this way, migration requires necessary cultural and psychological adjustments of individuals, affecting their cultural identities (Batista-Pinto Wiese 2010).When migrants leave their original location, where they have built their first and essential cultural and psychological identifications, they often adjust their identities to the new culture in a process of acculturation and deculturation (Kim 2001).However, this change or adjustment is not usually a smooth process, as emotional concordance with the host culture might create unpleasant feelings.

Conclusions
This paper analyses the concept of migration with a particular focus on its definition, types, causes, and effects.Although migration is an integral part of human history, the concept of migration has been complicated over time and space (Skeldon 2017).Hence, this paper explores the complexity of the concept of migration to provide a better definition of migration or a migrant beyond time and space limitations.Moreover, through Lee's (1966) push and pull model, the paper indicates that migration is caused by local and global factors.
This paper also outlines the distinctive features of refugees from other migrants such as economic migrants.Refugees are left with no option but to flee their original place for their safety (Bauman 1996).However, many choose their destination country based on the asylum recognition rate (James and Mayblin 2016) and socio-economic opportunities (Brǎdǎţan and Kulcsár 2014;Docquier and Rapoport 2008) the country offers.Hence, they undertake a long, risky, and costly journey to reach those countries (International Organization for Migration 2017; Llanni 2016).On the other hand, this paper argues that migration has socio-economic and psychological effects on the individual migrants and their origin and host countries.
Migration has long been an extensively researched concept but remains a source of debate among scholars, politicians, and other groups affecting millions of migrants, particularly refugees and asylum seekers.The paper contributes to advancing knowledge and increasing people's understanding of international migration by interrogating the concept, and its causes and effects.It is also expected to instigate further discussion on related issues that are not adequately discussed in this paper.For instance, it is important to further study the specific features and identities associated with the lasting concept or identity of "migrant" after naturalisation or adoption of another citizenship.