Disability and Older Age Return Migration: Evidence Against the Salmon Bias

Mexican immigrants make up an increasing proportion of the US population 65 and older. Whereas this population has among the lowest rates of disability at working ages, there is growing evidence of high rates of disability at older ages, findings which contradict what mechanisms of selection, namely the “salmon bias,” would predict. However, largely due to data limitations disability rates between those who stay in the US into older ages and those who return to Mexico are rarely compared. Here two waves of data from the US based Health and Retirement Study and the Mexican Health and Aging Study are combined to create a novel dataset that enables an interrogation of the widely held assumption of negative selection on health among return migrants. Investigating three measures of functional limitation and disability, results show higher prevalence of disability for stayers as compared to both younger and older returnees. These results are robust to controls for childhood background, adult socioeconomic status, and migration related variables and hold for those who immigrated during different immigration policy regimes. These findings are novel not only because they stand in opposition to previous assumptions about the direction of health selective return migration, but also because they mean that those remaining in the United States into older ages are among the most vulnerable.

Salmon bias effect as hypothesis of the lower mortality rates among immigrants in Italy

Compared with natives, immigrants have lower all-cause mortality rates, despite their lower socioeconomic status, an epidemiological paradox generally explained by the healthy migrant effect. Another hypothesis is the so-called salmon bias effect: “statistically immortal” subjects return to their country of origin when they expect to die shortly, but their deaths are not registered in the statistics of the country of residence. This underestimation of deaths determines an artificially low immigrant mortality rate. We aimed to estimate the potential salmon bias effect on differences in mortality rates between Italians and immigrants. We used a national cohort of all Italians registered in the 2011 census and followed up for mortality from 2012 to 2016. Mortality data were retrieved from the Causes of Death Register, which included all deaths occurring in the country and the Resident Population Register, which collects also the deaths occurring abroad. We assumed as a possible salmon bias event the death of an immigrant resident in Italy that died in his/her country of origin. Considering the deaths occurring in the country of origin, we observed an 18.1% increase in the overall mortality rates for immigrants and an increase of 23.7% in the age-standardized mortality rate. Mortality rates of immigrants resident in Italy, calculated without taking into account the deaths occurring in the country of origin, are certainly underestimated. However, the salmon bias only partly explains the difference in mortality rates between immigrants and Italians.

The Citizenship Advantage in Psychological Well-being: An Examination of the Hukou System in China

Given that Chinese migrants with rural hukou status are not considered full citizens in their urban destinations, rural-urban hukou conversion signifies full citizenship attainment in urban China. We assess causal effects of three major types of urban hukou attainment—merit-, policy-, and family-based hukou conversion—on migrants' psychological well-being in middle- and later-life. We further examine how hukou matters—how periods and hukou destinations alter the values of specific urban hukou and their psychological health implications for individuals. We use the China Health and Retirement Longitudinal Study (2015 data) and life history data (for 2014) for analysis. To assess the extent to which the salmon effect contributes to estimation bias for migrants, we compare results from a sample with current migrants and one with current and returned migrants. To address for selection into hukou conversion, we adopt inverse probability–weighted regression adjustment methods. We show that the salmon bias significantly dampened causal estimates. Merit- and policy-based hukou conversion has protective effects on psychological well-being. Policy-based converters have better psychological health than other types of converters. Hukou conversion in the pre-1978 period conveys greater psychological benefits than that in the post-1998 period, when economic and social values of urban hukou have decreased. Hukou converters in the cities with the most resources enjoy better psychological well-being than their counterparts in other cities. Our study joins the emerging literature in investigating how citizenship conveys advantage in health and well-being. We discuss these results in the global context as well as the context of China's decades of evolution of hukou policy and the urbanization process.

Has Rural-Urban Migration Promoted the Health of Chinese Migrant Workers?

The relationship between health and migration has always been an important theme in immigration research. This research develops a new approach to test the healthy migrant hypothesis and the salmon bias hypothesis in China by examining an interaction term combining agricultural hukou and migrant status, non-agricultural employment history, and subsequent area of residence. Based on two Chinese micro-databases, CGSS 2015 and Harmonized CHARLS, we conducted an empirical test on the relationship between migration and health. Our empirical evidence suggests that the initial health advantage among Chinese rural migrant workers was largely due to self-selection rather than migration effects. After controlling for demographic and socioeconomic characteristics, this advantage disappeared. After their health deteriorated, migrant workers returned to their original location. This could exacerbate the contradiction between the allocation of medical resources and the demand in rural and urban China, further intensifying the already widening health status gap between rural and urban residents.

Impact of Occupation and Family Burden on Psychological Adjustment in Returning Migrants

Background: Recently, increasing returning migrants in China accompany the massive rural-urban migration, but little information on mental health is available. Methods: A cross-sectional survey was conducted in 2,100 households from seven provinces to examine the effect of return migration on mental health and its association with entrepreneurial experience, occupation, and family burden compared with local rural non-migrants. The 12-item General Health Questionnaire (GHQ-12) was used to measure mental health status, and factor scores were extracted through factor analysis to gauge three sub-domains of loss of confidence, social dysfunction, and anxiety. A general linear regression model was used to analyze the data for the association. Results: Returning migrants were more likely to have elevated levels of anxiety compared with rural non-migrants when adjusting for social and demographic variables. Entrepreneurial experiences reduced loss of confidence and social dysfunction but increased anxiety; started but not currently running a business, and having older adults at home to care seemed growing concern in returning migrants but not in the rural non-migrants. Conclusion: Our study supports the salmon bias effect, but that occupation, entrepreneurship, and family burden may have non-negligible impacts on the anxiety in returning migrants. The findings may have implications for promoting social integration for returning migrants.