Published papers

Despite the vast literature on birth-order effects in developing countries, there has been little research on their long-term changes. This study uses three population censuses of Cambodia to investigate how birth order affects educational attainments and how its effects changed over time. We estimate regressions with family fixed effects and cohort fixed effects, and present four findings. First, later-born children are less likely to enroll in primary school and gain literacy skills, and end up with fewer years of schooling than first-born children. Second, controlling for gender differences in education, we find smaller birth-order effects for girls. Third, there is a strong relationship between the gender composition of siblings and birth-order effects. Finally, not only have these birth-order effects attenuated over time but the relationship between the gender composition of siblings and birth-order effects has also changed. In the 1998 census, if the firstborn child is male, his sisters’ educational outcomes are influenced more by their birth order compared with his brothers. In contrast, in the 2019 census, if the firstborn child is male, his sisters' educational outcomes are less susceptible to birth-order effects compared with his brothers. Our findings indicate gendered economic disparities within households and their long-term changes.

We examined the effects of Vietnamese enterprise zones, under the initiative of the central government, on local businesses across different types of ownership of zone infrastructure developers (ZIDs). We constructed a panel of communes during 2000–2007 using data on zone-based firms, local firms, and zones. We found that zones led to an increased number of firms and increased employment in the communes hosting the zones, even after excluding zone-based firms. Our findings also suggest that private partnerships in ZIDs worked best in attracting firms to the zones. The spatial spillover effects of the zones occurred up to a distance of 14 km.

Orphanhood has long-term adverse effects on human capital formation but its short-run effects are mixed. We examine the short-run effect of improved access to safe water on orphans’ outcomes in rural Zambia. We utilize a unique dataset collected in a quasi-experimental setting from a groundwater development project and employ a difference-in-differences approach. We do not detect any immediate effect from new water access on health and educational outcomes. However, we observe a larger increase in time spent on water collection and water-related household chores for orphaned girls than for non-orphans living with their biological mothers. We conclude that orphaned girls are disadvantaged in that they are more responsible for collecting water and related household chores under improved access to safe water, although the availability of safe water per se benefits the whole population.

Lack of access to high-quality education remains a serious concern in many developing countries. This is especially the case for rural areas, including islands suffering from a shortage of skilled teachers and sufficient educational equipment. We examine the impact of introducing TV-aided model lessons in class to enhance the quality of teaching (the EQUITV project) on the national examination test scores of Mathematics and “Combined Subject” (a comprehensive subject comprising 30% science and 70% social studies and other topics) as well as English in the final year of primary education in Papua New Guinea. We employ a panel event study to capture the different timings of the intervention across schools over multiple time periods. We find that the project significantly and robustly improved test scores for girls only in English 3 years after the introduction of the project, but no improvement was seen for boys.

Access to safe water sources remains scarce in sub-Saharan African countries. We estimate the economic value of safe water from newly constructed boreholes in rural Zambia. Our quasi-experimental setting allows us to estimate the revealed preference measure of new safe water sources in a causal way, empowered by precise information on water collection and distance to new facilities. We show that the share of time value for water collection in total expenditures was about 10% at the baseline survey, which was reduced to about 3% at the end-line survey, but the difference-in-differences analysis reveals that the project did not reduce the time burden for collecting water due to the greater demand for safe water. The main net benefit of the project lies in improved productivity due to decreased diarrhea incidence among working-age adults. The estimated internal rate of return of the project is not large. However, the project is likely to have additional dynamic health benefits due to the decrease in disability-adjusted life years (DALYs), corresponding to 192.3 USD per DALY and 6.88 USD per household.

Using an unbalanced panel of 539 Vietnamese districts from 2000 to 2010 and the corresponding politicians’ profiles, we examine firm behaviour in response to favouritism by top-ranking politicians towards their districts of birth. Results show that the number of firms tend to increase in the home districts of politicians after they assume office. This favouritism is particularly pronounced for private domestic firms, construction firms and rural areas. However, state-owned firms are indifferent. We discuss the non-response of state-owned firms, potential mechanisms and channels behind the statistical results.

Farmland degradation caused by excessive use of agrochemicals is a serious environmental concern, and thus the use of organic fertilizers is encouraged for sustainable agriculture in Vietnam. However, the adoption of organic fertilizers among farming households has been slow, spontaneous, and fragmented. The absence of credible information and advisory sources is reported to be a critical constraint. The sharing of information and experiences among social networks is expected to play an important role in overcoming this constraint, although strong causal evidence remains scarce. Therefore, this study employs an instrumental variable approach with observational village-census data to identify the causal impacts of social networks on the adoption of organic fertilizers and explores the underlying information-sharing mechanism within social networks, providing rich information about existing social networks for both men and women separately. The estimation results show that in farming households, the wife's social networks have a positive and significant effect on the diffusion of organic fertilizers. Our findings highlight the role of information exchange, experience sharing, and agricultural collaboration among groups of women in enhancing pro-environmental agricultural practices in suburban villages of Central Vietnam.

Incorporating the internet-based measure of discrimination obtained by Google Trends into state-level panel data, we conduct a fixed-effect model estimation to elucidate the relationship between racial discrimination and depression among Black people. We find that the deterioration of mental health among Black people, measured as the percentage of Black people with depression, is closely associated with our measure of discrimination.

Japan has faced a decline in fertility since the coronavirus disease 2019 (COVID-19) pandemic. This study aimed to investigate the rate of pregnancy postponement and its contributing factors, with a particular focus on economic- and COVID-19 infection-related indicators. This study used data from 768 observations of married women aged 18 to 50 years with pregnancy intentions. The data were obtained from two rounds of a large web-based survey conducted by the Japan COVID-19 and Society Internet Survey (JACSIS) in 2020 and 2021. A generalised estimating equation (GEE) model was employed, as well as Poisson regression models for sub-sample analysis divided by year to estimate the year differential magnitude of the contributing factors' impacts. Approximately 20% of married women with childbearing intentions postponed their childbearing. The analyses revealed that declining income and anxiety about future household finances were significantly related to delayed childbearing, while fear of COVID-19 and infection rate were not. Additionally, the adverse effects of unfavourable economic conditions were stronger in 2021. Notably, age did not influence the decision of pregnancy postponement. Older women postponed pregnancy just as much as younger women. In conclusion, this study confirmed that the COVID-19 pandemic, particularly its related adverse economic conditions, contributed to Japan's current baby bust. Considering that advanced maternal age is already common in Japan, this decreased fertility may result in the long-term negative consequence of further population decline.

We examine the possible impacts of enterprise zones (EZs) on local Vietnamese households between 2002 and 2008, using differences-in-differences and a panel-event study. We layer four waves of household surveys using a census of EZs in 2007, based on the same commune identity for our household and individual analyses. Within 5 years of EZ establishment, we find they are associated with higher household incomes, an increase in private property prices, and an increase in working hours. However, we do not find a significant impact on household living expenditure or school attendance/working probabilities among members aged between 7 and 17 years. Neither do we find a significant impact on health outcomes.

We examine the impacts of improved rural roads on villagers, using panel data of Cambodian villages (2006–2021). We apply econometric methods to deal with multiple treatment timings and multiple time periods in an event study. We find an association between the wealth of villagers and the improvement of rural roads. A higher minimum price for rice at the farm gate may be one of the reasons for the increase in wealth. We also find impacts of improved rural roads on (reducing) illiteracy rates among villagers. However, we do not find any statistically significant impacts on the school enrollment rate, structural change, or internal migration. Instead, improved rural roads lead to a higher share of families being subjected to environmental pollution. Our findings suggest that policymakers should have cautious expectations regarding the feasible impacts of improved rural roads.

We examine whether religion influences sex-selection behavior under a persistent son preference. Specifically, we investigate whether religion promotes a different sex ratio among children under 5 years of age and whether religiosity has externalities on secular households, using whole-population census data and religious establishments in Vietnam. The results show that the ratio of boys is lower among religious households in both commune fixed effects and the instrumental variable (IV) approach. Furthermore, using the 1955–1974 North–South Vietnam division that reallocated religious communities for another commune-level IV, we find that a higher pious follower ratio leads to a lower ratio of boys in the secular population.

© 2018 John Wiley & Sons Australia, Ltd We decompose the gender wage gap in terms of wage distribution in Vietnam during 2002–2014 using two methods. The first method uses two estimated counterfactual distributions; the second uses an estimated recentred influence function. We focus on the formal sector and find evidence for a consistent gender wage gap, with the price of skills being the main contributor. In contrast, labour market discrimination does not have a crucial influence. Some gender equality gained by the distribution of skills can be explained by the rise in women's education and women's participation in specific industries, occupations and the growing private sector.

© 2018 Walter de Gruyter GmbH, Berlin/Boston. In literature, there is limited direct evidence regarding the effect of health insurance coverage on firm performance and worker productivity. We study the impacts of health insurance on medium-and large-scale domestic private firms' performance and productivity in Vietnam, using a large firm level census dataset. We find statistically, but suggestive, positive health insurance effects on both aggregate profit and profit per worker for both complying and non-complying firms when using the full sample. We further restrict the sample to specific industries. The positive health insurance effects could exist for both complying and non-complying firms in the heavy manufacturing and construction sector, while such positive effects could be only significant for complying firms in the wholesale/retail sectors. We could not find any evidence of positive health insurance effects in the light manufacturing sector. These results imply that the impacts of health insurance could be industry specific.

© 2018 Elsevier Inc. This study provides the first evidence on a variety of life course outcomes of birth weight in Japan by employing new datasets covering the middle and older generations. We have several interesting observations. First, low birth weight is significantly associated with adverse outcomes in early life including school performance and self-rated health. Second, no negative effect of low birth weight is found on educational attainment or primary job status. Third, health outcomes due to low birth weight at older ages are not negatively affected except for difficulty in mobility and higher risk of diagnosis with hypertension or diabetes. Overall, our findings suggest that the negative effect of lower birth weight seems to fade out over the life course.

© 2017, © 2017 Informa UK Limited, trading as Taylor & Francis Group. We investigate how rice farmers’ risk preferences affect the adoption of post-harvest technology in Cambodia, focusing on moisture meters. We find that risk-averse farmers are more likely to adopt moisture meters, although the degree of farmers’ loss aversion or the extent to which they tended to overweight small probabilities do not affect the adoption. In the setting of our study, the effects of farmers’ risk preferences on agricultural technology adoption can be described by using expected utility theory. However, controlling for loss aversion and probability weighting improves the precision of examining the effects of farmers’ risk preferences on adoption.