Sunghun Lim and SongYi Paik (2022), “Immigration Enforcement and Agricultural Employment,” Applied Economics. [Link]

Abstract: Immigration enforcement often brings unintended consequences in domestic labor markets. Using the universe of administrative immigration data from 2005 to 2019, we uncover evidence that the E-Verify, an employment verification mandate, exacerbates the ongoing farm labor shortage in the US. Relying on the newly developed staggered difference-in-differences method, we find that the E-Verify policy restricts the employment of undocumented farmworkers. Our results indicate that domestic workers are not being replaced with declined undocumented workers wherein the inflow of the H-2A visa migrants still remains. Our finding advances a more nuanced picture of the US labor shortage driven by the E-Verify policy. This paper contributes to the rising policy debate on reforming nationwide E-Verify enactment and the H-2A visa program in the US.

SongYi Paik, Dung Le, Lien Nhu, and Bradford Mills (2020) “Salt-tolerant rice variety adoption in the Mekong River Delta: Farmer adaptation to sea-level rise,” PLoS ONE 15(3):e0229464. [Link]

Abstract: Rice production in the Mekong River Delta of Vietnam (MRD) is endangered by sea-level rise and an associated increase in the incidence of salinity intrusion. This paper examines the diffusion of salt tolerant rice varieties in the MRD that were promoted through Consortium for Unfavorable Rice Environments (CURE) activities. Factors associated with adoption of CURE-related varieties are estimated using a random utilty model and a dataset of 800 farm households with rice fields in salinity prone areas of the MRD. Results suggest that there has been widespread adoption of CURE-related varieties in salinity-prone areas. Further, multivariate analysis reveals that environment and location characteristics, rather than household characteristics, are the most important determinants of adoption. In particular, CURE-related varieties are more likely to be adopted in high-salinity-risk areas that are not protected by salinity barrier gates. Neighbhors’ adoption decisions also strongly influence household decisions to adopt CURE-related varieties. The contracting of mechanization, particularly for land preparation and harvest, requires the coordination of village households in timing of planting, harvest and varietal duration. This coordination appears to extend to choice of CURE-related varieties. Finally, CURE-related varieties and other varieties generate similar net revenues in a year with low salinity exposure, suggesting that CURE-related varieties are a low-cost insurance policy against salinity inundation in high risk areas. Combined, these results highlight the need to address complex factors beyond current economic profits, like environment, community choices, and risk mitigation, when designing technologies and policies that support farmer adaptation to climatic change.


SongYi Paik, “The Agricultural Minimum Wage, Guest Workers, and US Workers.” [Link]

Abstract: American agricultural employers have relied on guest workers but are required to pay them at least the minimum wage, known as the Adverse Effect Wage Rates (AEWRs). Using a border discontinuity approach, I find that the AEWRs led to an increased employment of less-educated agricultural workers, especially for citizen Hispanics but had insignificant effects on other groups of agricultural workers. Further analysis indicates a consistent pattern in the outcomes for hours of work and hourly wages. This suggests that higher AEWRs do not adversely affect American workers and may attract less-educated citizen Hispanics who were previously receiving lower wages. Moreover, higher AEWRs are unlikely to discourage the hiring of guest workers, potentially due to a lack of viable substitution options for employers. While employers can hire more workers, they need to bear higher labor costs.

SongYi Paik, “Slow Violence of Waste: Evidence from Chinese Environmental Policy in Waste Trade.” [Link]

Abstract: Since the 1990s, China has been the largest importer of waste in the world. However, in 2018, China changed its policy to prohibit the import of plastic, paper, and textile waste. This change in policy raises the question about where the waste will go now. Using a difference-in-difference approach, this study analyzes the effects of the 2018 Chinese policy change on global waste exports and re-exports. The evidence suggests that this policy has a positive impact on both the extensive margin (probability of waste export) and the intensive margin (quantity of waste export), particularly with substantial effects on the intensive margin of exports and re-exports to upper-middle-income countries and the East Asian & Pacific regions. This paper also uncovers evidence of pollution haven effects, indicating that waste is exported to countries with lax environmental regulations, potentially affecting residents in those regions.


Sunjin Kim, SongYi Paik, and Doojin Ryu, “Military Alliance, Geopolitical Risk, and Global Energy Trade.”

"The US Farm Labor Shortage during Covid-19 and Farmers' Adaptation" with Terry Hurley