It has been suggested that migrants are not representative samples of their population of origin. Migrants are likely to be positively selected when they respond to pull factors in the country of destination and negatively selected in respond to push factors in the country of origin (Lee, 1966). With regards to health, this leads to the so called “healthy migrant effect”. In general, people that are younger and healthier are more willing and able to migrate (Jasso et al., 2004). The elderly and people that are ill tend to stay in their country of origin. So, this selection results in migrants that tend to be healthier.
