手法を比較

	Migrant Network Analysis	Diaspora Engagement Mapping
分野	Migration Studies	Migration Studies
系統	Process / pipeline	Process / pipeline
提唱年	1990	2014
提唱者	Douglas S. Massey	Alan Gamlen
種類	Network and feedback pipeline for migration self-perpetuation	Inventory-and-classification pipeline for state diaspora policy
原典	Massey, D. S. (1990). Social Structure, Household Strategies, and the Cumulative Causation of Migration. Population Index, 56(1), 3-26.	Gamlen, A. (2014). Diaspora Institutions and Diaspora Governance. International Migration Review, 48(s1), S180-S217.
別名	Migration Network Analysis, Social Capital Migration Analysis, Cumulative Causation Analysis, Network Prevalence Migration Model	Diaspora Institution Inventory, Emigrant Engagement Policy Mapping, Diaspora Governance Mapping, Origin-State Diaspora Policy Audit
関連	3	3
概要	Migrant network analysis studies the interpersonal ties — of kinship, friendship, and shared origin — that link prospective migrants to people who have already migrated, and treats these ties as a form of social capital that lowers the costs and risks of moving. Douglas Massey's 1990 article argued that once a few pioneers establish themselves at a destination, they reduce the difficulty of migration for everyone connected to them: relatives and friends can draw on their information, housing, job leads, and support, so each successful move makes the next one easier and more likely. This dynamic produces cumulative causation, a self-feeding process in which migration alters the social and economic context of the origin community in ways that promote still more migration, until flows acquire a momentum largely independent of the conditions that first set them off. Massey and colleagues' 1993 review codified network theory as one of the perpetuating mechanisms of international migration, distinct from the factors that initiate it. The analysis maps the network of ties, measures the prevalence of migration experience in a community, and models how that prevalence raises individual migration probabilities. It explains why migration streams, once begun, are so difficult to stop.	Diaspora engagement mapping is a systematic method for inventorying the institutions and policies through which states reach out to, claim, and govern their populations abroad. Alan Gamlen's 2014 work on diaspora institutions and diaspora governance showed that since the 1990s a striking number of states have created dedicated ministries, offices, councils, and programs aimed at emigrants and their descendants, turning the diaspora into an object of deliberate statecraft. The method catalogues these bodies and classifies what they do, distinguishing capacity-building (cultivating a diaspora identity and the institutions to reach it), extending rights (offering citizenship, voting, and protections abroad), and extracting obligations (mobilizing remittances, investment, lobbying, and taxes). By coding which instruments each state deploys and how they change over time, the analyst maps the evolving web of ties binding origin states to their emigrants. The product is both a descriptive atlas of who is governed how and an analytic tool for comparing diaspora-engagement strategies across countries and explaining why they spread.