We conducted large-scale lost letter experiments in Beijing, a megacity with more than 21 million residents, to test if the observed altruistic attribute of the letter recipient would induce more passersby to return the lost letters. The treatment letters were addressed to a nationally renowned...

We estimate the effects of early childhood malaria exposure on education and health at older ages by exploiting variations in malaria exposure risk around birth that resulted from a universal malaria eradication campaign in colonial Taiwan in the early 20th century. We find that malaria exposure...

We conducted a large-scale lost letter experiment with a novel design across all seasons in Beijing to study whether ambient air pollution influences helping behavior. We assessed air pollution by PM2.5 and PM10. Our novel design allowed us to collect real-time granular data from the streets. To...

We identify the causal effect of teacher qualifications on parents' investments in their children. Exploiting a unique, high-stakes educational setting in which teachers are randomly assigned to classes, we show that parents react to more qualified teachers by increasing their financial...

Using a natural experiment in Taiwan, this paper shows that exposure to male-biased sex ratios at the marriageable ages is associated with a greater likelihood of death in later life. Half a million soldiers from Mainland China who retreated to Taiwan after a civil war in the late 1940s were...

For decades, the debate on using DDT to control malaria has focused on the balance between immediate public health gains and ecological costs, ignoring DDT's long-term harmful effects on humans. Using data from the large-scale indoor residual spraying of DDT that took place in Taiwan in the...

We draw attention to two identification issues with previous studies that utilized tertiary education expansion to estimate the causal effect of education on fertility: (i) the mis-categorization of women past the usual college-entry age as "unexposed" to the expansion, and (ii) a possible...

Sexual activities between consenting adults of the same sex are still criminalized in more than one third of the countries in the world despite a global wave of decriminalization in the past sixty years. This paper empirically investigates the effect of sex ratios, i.e. relative number of men to...

University students have been particularly affected by the COVID-19 pandemic. We present results from the first wave of the Global COVID-19 Student Survey, which was administered at 28 universities in the United States, Spain, Australia, Sweden, Austria, Italy, and Mexico between April and...

The Vietnam War occurred when Vietnam was divided into two states with contrasting institutions. North Vietnam was characterized by a command economy under a stable political regime, whereas South Vietnam experienced a market economy and prolonged political instability. This paper uses this...