Many older adults miss life-saving influenza vaccines each winter, especially in low- and middle-income countries. We conducted a factorial randomized controlled trial testing three interventions: (i) a U.S.-style reminder nudge, (ii) one-off multi-valued subsidies ranging from USD 1.50 to 15, and (iii) cost information introduced after re-randomization. The reminder nudge and cost information had no impact on vaccination behaviors. One-off subsidies substantially increased both vaccination intentions and behaviors, with small incentives (from USD 3 upward) more than doubling uptake. Subsidies also raised re-vaccination the following year. Returns to vaccination were heterogeneous, with greater medical cost savings among individuals with lower unobserved resistance. On average, influenza vaccination saved USD 431 in medical expenses, yielding a benefit–cost ratio of 40.

Opioid addiction is a major problem in several countries, but effective medicationassisted treatment is underused. Beyond issues of self-control, a key factor contributing to poor treatment adherence may be the lack of positive self-image, perhaps because of social isolation and a sense of exclusion. We examine the determinants of treatment adherence by studying a randomized controlled trial of two interventions aimed at improving adherence to Methadone Maintenance Treatment (MMT) and their impacts on health and other quality-of-life measures. The first (benchmark) intervention (T1) offers cash incentives conditional on individual attendance and leads to better adherence and health during the incentive period. The second (social) intervention (T2) offers a much weaker financial incentive to the individual but strengthens social identity, particularly for those randomly assigned to high-performing teams. Despite offering substantially lower per-person financial incentives, T2 nearly matches T1’s impact on attendance (and surpasses it for those in the high-performing teams), highlighting the effectiveness of social identity for motivating treatment adherence.

This paper proposes a two-step ``\emph{test-feedback}" intervention focused on aligning parental beliefs with their children’s abilities and interests. The intervention includes two treatment arms: self-learning information (T1) and online teacher-guided information (T2). We involved nearly 4,000 students and their parents from four middle and high schools in western China. Over six months, both treatment arms led to a 0.12 standard deviation decrease in students' CES-D scores, equivalent to a 5 percentage point reduction in depression. Treated students also experienced less stress and improved self-esteem. We find that enhanced alignment between parental beliefs and their children's needs indeed plays a role in driving these outcomes.

According to UNESCO, one-third of the world’s youths are victims of bullying, which deteriorates academic performance and mental health, and increases suicide ideation and the risk of committing suicide. This paper analyzes a four-month parent-directed intervention de- signed to foster empathy in middle schoolers in China. Our implementation and evaluation study enrolled 2,246 seventh and eighth graders and their parents, whom we assigned, at the classroom level, to the control or intervention condition randomly. We measured, before and after the in- tervention, parental investments, children’s empathy, and self-reported bullying perpetration and victimization incidents. Our analyses show that, in the short run, the intervention increased invest- ments and empathy. More importantly, the program also indirectly reduced bullying incidents. In the longer run, additional evidence suggests that the reduction in bullying persisted for one year. The program also moved up treated students’ percentile rank in the high school entrance exam by 1.4 in two years. We measured costs and found that it costs $16.30 for our intervention to reduce one bullying incident. Our study offers a scalable and low-cost strategy that can inform public policy on bullying prevention in other similar settings.

The phenomenon of parents’ Middle-School Blues is widespread yet often overlooked. We find that parental mental health is “V-shaped” throughout children’s developmental stages, reaching its nadir during middle school. We then leverage data from a four-month parental involvement program on empathy and positive parenting. We find the program has a significant positive effect on parental mental health, measured by GHQ-12 score, by 0.17 standard deviation. The effect is large enough to help parents combat Middle-School Blues. We attribute the program’s effect on mental health to the improvement in parental skills, time inputs, and children’s non-cognitive ability. The mediation analysis suggests that these three factors interact and account for over 62% of the total program effects, and that the improvement in parental skills is the key driver of promoting parental mental health.

This paper examines the impact of a randomized experiment in Macedonia in which program applicants were assigned to receive a job interview and the employers were subsidized when job and worker were matched. The interview led to more than 25 percentage point increase in employment in the first 6 months, and the average effect persists, at around 15 percentage points after the subsidies has expired.

In many societies, parents prefer sons over daughters, but the well-being effects of child gender, especially in later life, are less studied. Using the latest two waves of the China Health and Retirement Longitudinal Study (CHARLS), this paper evaluates the impacts of having daughters on older parents' subjective well-being (SWB) in China, which has a rapidly aging population and the traditional preference for sons. Studying the cohort of parents whose child gender is as good as random, we find that having more daughters promotes older parents' SWB, especially overall life satisfaction, satisfaction with health, and satisfaction with children. Our results suggest that the increase in SWB is achieved through better health, more financial support from daughters, more spending on leisure and a lower probability of working. The positive SWB effects of daughters are found to be more salient among more vulnerable groups, including those who are older, less educated, and with fewer children. 

Is the rising perceived cost of childrearing discouraging fertility? How do people’s fertility plans respond to potential fertility subsidies? In two separate large field survey experiments in China, we answer both questions and propose potential interventions for boosting fertility in developing countries. Interestingly, we find that people with one or no child expect high costs of a second or third child, while people with more than one child manage to raise children inexpensively. TOT estimates show that a higher perceived cost of child leads to lower birth planning, suggesting that the high perceived cost for the low-birth population partially contributes to the low fertility rate. 

Bullying is on the rise among young people but the cause is unknown. This paper provides a first empirical study on the cause of being a bully by focusing on the within-class socioeconomic status (SES) inequality.