Convergence Theory and the Salmon Effect in Migrant Health
This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Global Public Health. Please check back later for the full article.
For decades, researchers have been puzzled by the finding that despite low socioeconomic status, fewer social mobility opportunities, and access barriers to health care, migrants appear to experience lower mortality than the majority population of the respective host country, and possibly also of the country of origin. This phenomenon has been acknowledged as a paradox and, in turn, researchers have attempted to explain this paradox through theoretical interpretations, innovative research designs, and methodological speculations.
Specific focus on the salmon effect/bias and the convergence theory may help characterize the past and current tendencies in migrant health research to explain the paradox of healthy migrants. The first examines whether the paradox reveals a real effect or is a reflection of methodological error; and the second suggests that even if migrants indeed have a mortality advantage, it may soon disappear due to acculturation. These discussions should encompass mental health in addition to physical health.
It is impossible to forecast the future trajectories of present migration patterns and equally impossible to predict, with full accuracy, the physical and mental health outcomes of migrants/refugees who cannot return to their country of origin due to the current climate. However, the ability to follow individuals on their path to becoming acculturated in new societies can both enrich our understanding of the relationship between migration and health, and contribute to the acculturation process by generating advocacy for inclusive health care.