Kupiszewski, Marek, Jakub Bijak, and Anna Kicinger. "The Use of International Migration Theories in Migration Forecasting — A Practical Approach". In International Migration and the Future of Populations and Labour Force Resources in Europe, edited by Marek Kupiszewski, 35-57. Dordrecht, Netherlands: Springer, 2013.

Kupiszewski, Marek, Jakub Bijak, and Anna Kicinger. "The Use of International Migration Theories in Migration Forecasting — A Practical Approach". In International Migration and the Future of Populations and Labour Force Resources in Europe, edited by Marek Kupiszewski, 35-57. Dordrecht, Netherlands: Springer, 2013.

• The first attempts to create a theory of migration date to the end of the 1800s, with the work of Ernst Georg Ravenstein, a German-English cartographer. Mr. Ravenstein asserted that migration was essentially motivated by economics, particularly observed in the flow of migrant from poor rural areas to wealthy and growing urban areas (35).
• Several scholars have attempting since Mr. Ravenstein to develop increased perspectives on geographical, historical, and political reasons for migration but since so many factors are involved in the decision to migrate, no general theory has emerged. The most basic theoretical tool remains 'push' and 'pull' factors (35-36).
• Historically, most research on migration focused on internal migration, with international migration only become the subject of scholarly attention in recent decades (36).
• Economic reasons for migration are based on Adam Smith's assertion that migration provides the means for the transfer of labour from areas of supply to areas of demand, meaning that immigration occurs between areas of high unemployment to areas of lower unemployment (36). This was disputed by John Hicks in 1932, who asserted that differences in wages was a larger determinate in migration than levels of unemployment (36-37).
• Neoclassical theories of economic migration capture both of these elements, arguing that migrants want to maximize the value gained through their migration, meaning that they factor in both higher wages and lower levels of unemployment in the decision to move and in choosing a destination, as well as different barriers or costs associated with migration (37).
• All of these economic theories of migration fail to account for social and cultural factors in motivating migration, and falsely assume that non-economic factors play a limited part. On the contrary, research shows that social, cultural, and political factors are extremely important, especially in explaining why people decide to emmigrate, an issue not dealt with in economic theories of migration (37-38).
• In an attempt to incorporate social elements into economic theories of migration, the school of 'new economics' has argued that households rather than individuals are the primary actors in migration, with individual members sent to supplement household income or cushion the household from local fluctuation in the economy through diversification (38). Unfortuntely the data needed to use this theory in calculations is ususally unavailable (38-39).
• The dual labour market theory claims that social status and cultural perceptions of work also play a part, if not a larger role, than wages differentials in motivating migration. Migrant will seek not only higher paid work, but also work with higher social status, with the relative value of these concepts depending on the immigrant group (39).
• Sociological theories of migration are based on a 'push-pull' model of migration factors, in which migrants emmigrate due to negative 'push' factors in their home areas and immigrant due to positive 'pull' factors in destination areas. The nature of these factors depends on the exact situation, and the influence of 'push' or 'pull' in migration affects the types of migrants produced (40).
• Research has shown that the most influential 'pull' factors are not actually economic, but the presence of networks of family or friends in the destination area. The availability of networks, either physical infrastructure or illegal trafficking networks, between states is also crucial in determining destinations (40-41).
• The cumulative causation theory argues that migration can be explained as a consequence of changing cultural and social circumstances at destination and source. This explans why migrants with new wealth from migration decide to return, despite doing so resulting in lowered wages, because they are able to return in a privileged social and economic position relative to that prior to migration (41).
• Politics plays a massive, and often unrecognized, position in determining migration simply through the creation of restrictions on immigration. Additionally, conflicts or crises causing massive out-migration have political origins (41). Changes in these political situations, especially changes to the laws governing immigration, have significant consequences for migration flows (42).
• There are a number of difficulties associated with actually predicting future migration patterns based on theories of migration. Most theories are not comprehensive enough to explain most forms of migration, rendering them inapplicable to the real world. Additionally, forced migration from conflict cannot be reasonably predicted (43). Those neoclassical theories which claim to be predictive through economic modelling tend to have extremely high levels of error (44).
• Push and pull factors determining migration can either be 'hard' or 'soft', with hard push factors necessitating emmigration to avoid armed conflict or starvation, and soft push factors being persecution, poverty, or any other non-life-threatening condition. In Europe, most push factors have been soft with the notably exceptions of emigration from Yugoslavia and the North Caucasus (45).
• Most of the political conditions for migration in Europe have been the process of democratization, which triggered simultaneous immigration of former emigres, and massive out-migration in cases where exit visa regimes had existed. The direction of these flows has been mainly determined by liberal immigration regimes in Western Europe, allowing  poor Eastern Europes to migrate there following the collapse of Communism (45).
• Discrimination also provide a large motivation for migration during the 1990s, as Russians immigrated from Eastern Europe to Russia and Belarus to avoid discrimination in newly independent states, as did Turks in Bulgaria and Romania (46).
• Future changes in European immigration policy are also likely to have a major effect on migration flows within Europe, especially considering the current trends towards policies more responsive to the perceived labour market needs of employers, curbing illegal immigration, and attempting to raise the skill-level of migrant workers (46-47).
• Currently, some of the largest employers in Europe remain the agricultural sector and heavy industry in Eastern Europe, the privatization of these sectors -- which are generally inefficient and in need of investment -- could led to a large migratory wave due to unemployment, likely heading from Eastern Europe to Western Europe (48).
• This pattern would make sense cosidering previous migrations within Europe, during which the greatest number of immigrants came from poor countries with inefficient economies to work in wealthy countries with the greatest efficiency. For this reason, rural parts of post-Communist Eastern Europe provided the most immigrants and urban areas of Western Europe received the most immigrants (49-50).
• Ethnic minorities have been an important immigrant group in Europe since the end of World War II, in particular the migration of Germans from Eastern Europe and Russia to West Germany. Since the end of the Cold War, these and other ethnic minority movement have decreased dramatically, with the exception of the Balkans (52). The other significant exception is the Roma, who will likely continue to migrant to Western Europe to escape the discrimination and violence against them common in Central and Eastern Europe (52-53).
• Economic factors can useful for predicting migratory patterns, but depend on accurate selection of statistics. For this reason, GDP per capita is a less useful economic predictor than average wage adjusted for purchasing power, which more accurately captures information of interest to potential migrants. Unemployment is another important factor, but still dependent on sectors of unemployment (47-48).