Research

Abstract: The Vietnam minimum wage unification policy was implemented in 2011 to unify the minimum wage levels for domestic and foreign-owned establishments. However, the policy brought an unintended consequence, as only formal sector workers are affected by this policy, leaving the workers in the informal sector unaffected. This study uses the Vietnam Household Living Standard Survey (VHLSS) 2010 - 2020 panel data to investigate the impact of the policy on the income gap between formal (treated) and informal (control) sector workers. Using the difference-in-differences approach as an identification strategy and the propensity score matching (PSM) as a robustness check, the study shows that the policy increased the household income of formal sector workers by 6.3 percent compared to their informal sector counterparts. The more pronounced impact is found among females, young adults, non-Kinh people, low-skilled workers, and people in the lower-tail income distribution.

Abstract: In 2011, the Vietnam government implemented a unique minimum wage policy that unified the regional minimum wages of domestic firms and foreign establishments. Using three panel data sets—the Vietnam Enterprise Survey (VES: 2007-2018), the Small and Medium Enterprises Survey (SMES: 2009-2015) and the Vietnam Household Living Standards Survey (VHLSS: 2008-2018)—the paper identifies a comprehensive effect of the minimum wage unification policy on both individual and firm-level employment. The results show that the policy has affected businesses at both the extensive and intensive margins. The minimum wage unification policy has reduced employment while increasing the working hours of those who remain employed. Companies responded quite differently, depending on their characteristics. In particular, small and medium-sized enterprises are more likely to replace regular and full-time workers with irregular workers and workers without formal labor contracts. As a result, workers were affected differently according to gender, industry, type of work, working status, firm size, and other factors. The increase in minimum wage of domestic firms also affected people who were not initially covered by a minimum wage, such as unpaid family workers. These results are robust across several sensitivity checks. 

Abstract: The study used a sample of 2,466 adults, including 1,543 wildfire-exposed residents of Maui and 923 unexposed residents from other Hawaii counties, to estimate the causal effects of wildfire exposure and disaster-induced displacement on depression, anxiety, and suicidal ideation among adults. Data were collected from January through December 2024 through the Maui Wildfire Exposure Study and the UHERO Rapid Health Survey. Residential addresses at the time of the fires were geocoded and linked to official burn zone perimeters to classify exposure. The results showed that wildfire exposure was associated with markedly increased odds of depression (odds ratio [OR], 2.85; 95% CI, 2.19–3.70), anxiety (OR, 3.39; 95% CI, 2.47–4.66), and suicidal ideation (OR, 3.06; 95% CI, 1.38–6.82) compared with matched controls. Elevated risk was also observed among residents outside the burn zone but within Maui, indicating a graded psychological impact. Displacement to temporary housing substantially increased risk, whereas employment was strongly protective. Findings were robust across multiple sensitivity analyses.

Abstract: This study aims to investigate and decompose the effect of peers on work performance through two specific channels: peer performance information and peer communication. The participants performed a real-effort task of adding the two highest numbers from a pair of 4x4 matrices and were paid by piece rate under four different treatments. The treatments differed in whether peer performance information on a randomly matched other participant was provided, and whether the matched participants could communicate via chatbox. Overall, I found that the presence of both peer information and communication increases individual productivity. Peer presence significantly raises the productivity of low performers, but has no effect on high performers. Peer presence significantly increases the productivity of both males and females; a stronger effect is found in the female group. My experimental results also connect to the literature on gender differences in the competitive environment.

Abstract:  We examined the effect of peer information and peer communication on individual performance under four different compensation schemes that are used in organizations: individual piece rate (based on individual performance), perfect substitutes (based on the average team performance), weakest-link (based on team members’ worst performance by task), and best-shot (based on the team members’ best performance by task). The participants performed a real-effort task of adding the two highest numbers from a pair of 4x4 matrices under four different treatments. In the overall sample of 154 experimental participants, we found that compared to the individual piece rate, the individual productivity, the group productivity, and the payoff per period are lower in the perfect substitutes. Given a higher initial capacity, the individuals exerted less effort in performing the task in the social dilemma. The social dilemma is driven by a free-riding mechanism among women, whereas the sucker effect mechanism is behind among high performers and competitive individuals. We also found that individuals in the weakest-link have lower individual productivity, lower group productivity, and lower payoff per period than those in the individual piece rate. In contrast, the individuals in best-shot have higher group productivity and higher payoff per period than those in the individual piece rate. The participants also utilized the chat box to divide and specialize the task to increase their payoffs in the best-shot. Due to the high opportunity cost of communication, people are more likely to focus on their own task in the individual piece rate. We also found that performance is influenced by participants’ individual preferences: people who are classified as competitive group have a better productivity than non-competitive people.