Selection of Communities
A variety of communities have been sampled in order to provide a basis for comparative study and generalization. These communities have been chosen to provide a range of different sizes, regions, ethnic compositions, and economic bases. The process of selecting communities for the LAMP has traditionally relied on anthropological methods. Communities are chosen after a personal reconnaissance of the geographic area to be studied by the principal investigators.
The only demographic fact regularly considered was the community’s sex ratio, which offer general picture of the intensity of the process of international migration. After an initial round of fieldwork, investigators compared their preliminary data with census statistics and formation available from bibliographic sources. However, the LAMP has never explicitly sought to survey only communities with high rates of out-migration. Investigators simply seek to corroborate that there is some migration from the community in question before proceeding. Then they select four specific locations to represent each of four levels of urbanization: rural area, with fewer than 2,500 inhabitants; pueblos (towns), having 2,500 to 10,000 inhabitants; mid-sized cities containing 10,000 to 100,000 inhabitants; and finally, a metropolitan setting, usually a particular neighborhood within in a state’s capital city or some other large city.
In the pueblos and small rural areas, investigators conduct a complete census of dwellings and undertake random selection from the resulting list. In mid-sized cities and urban metropolises, investigators generally chose a traditional, well-established neighborhood–one not dominated by recent rural-urban migrants. As a result, the urban samples are in reality samples of urban n neighborhoods or specifically demarcated quarters. In all cases, the neighborhood must have at least 1,200 enumerated dwellings, from which a random sample of 200 is taken.
The methodology of the LAMP thus yields results with a high degree of representativeness at the community level, and in some of the smaller pueblos and ranchos investigators have been able to survey every household in the community. Given that the sample is not targeted to migrants per se, but surveys the community as a whole, the project needs a fairly large sample size to generate a significant number of migrants. Traditional methods of cluster sampling generally survey small numbers of respondents across a large number of areas, but this generally yields small numbers of migrants to study an inability to make generalizations at the community level. For example, rather than interviewing 20 households in five communities we interview 100 households in one community, thereby enabling us to make generalizations about migratory processes at the community level. If the frequency of migration is 30%, on average the surveys would contain only six migrants in each of the five communities, rather than 30 migrants in one community.