Published papers

This paper examines the short-term impact of improved access to safe water on adult health and time allocation at newly constructed boreholes in rural Zambia. We employ a difference-in-differences estimation using a dataset collected under a quasi-experimental setting. We observe that improved access to safe water reduced diarrhoeal incidence among working-age adults and the resulting decrease in the number of days during which they could not perform their regular activities due to diarrhoea, although the economic benefits resulting from health impacts were very limited. With respect to time allocation, we find that improved access to safe water reduced time spent on water-related household chores of female adults. We do not observe any significant increase in time spent on income-generating activities. Instead, the time-gain benefit for working-age adults can be found in leisure time, particularly among females who live near the new boreholes.

This study measures the impact of the number of people who passed the Vietnamese imperial examinations (1075–1919) on the present-day quantity and quality of education in their home districts. Our analyses at the district and individual levels are based mainly on the data of successful imperial test takers, the 2009 population census, and 2009 National Entrance Exams to University test scores. We find a persistent legacy in educational attainment outcomes. Although there may be multiple channels that explain the long-term historical effects, a tradition of human capital investment and cultural elements are among the most important factors.

This paper examines long-term consequences of one of the most serious catastrophes ever inflicted on humankind: the atomic bombing that occurred in Hiroshima in 1945. While many victims died immediately or within a few years of the bombing, there were many negative effects on survivors in terms of both health and social/economic aspects that could last many years. Of these two life factors, health and social/economic aspects, the latter has largely been ignored by researchers. We investigate possible long-lasting effects using a new dataset covering the middle and older generations in Hiroshima some 60 years after the tragedy. Our empirical results show that Atomic Bomb Survivors did not necessarily suffer unfavorable life experiences in terms of the average marriage status or educational attainment but did experience significant disadvantages some aspects including the husband/wife combination of married couples, work status, mental health, and expectations for the future. Thus, survivors have suffered for many years after the catastrophe itself.

Background: The COVID-19 pandemic has affected every aspect of our lives, including the decision to become pregnant. Existing literature suggests that infertility and the decision to delay childbearing at a younger age are associated with a lower level of well-being and regrets when women start to desire a baby. Thus, the decision to delay childbearing due to the pandemic could negatively affect the well-being of women. This study focuses on how pregnancy decisions affect the well-being of women during the COVID-19 pandemic. Methods: From the Japan COVID-19 and Society Internet Survey, a nationally representative web-based survey, 768 observations of married women aged 18 to 50 years who had the intention of getting pregnant during the pre-pandemic period (conducted in 2020 and 2021) were used. Loneliness, severe psychological distress, and suicidal ideation were used as well-being indicators. For pooled data, a generalised estimated equation (GEE) model was used to estimate how pregnancy decision related to well-being indicators. For a sub-analysis, the sample was divided by the survey year and a Poisson regression model was used. Results: The GEE analysis showed an association between delaying childbearing and severe psychological distress, with the prevalence ratio (PR) being 2.06 [95% CI (1.40–3.03)]. Furthermore, loneliness and suicidal ideation that occurred after the beginning of the pandemic were significantly related to the decision to delay childbearing—1.55 [95% CI (1.03,2.34)] and 2.55 [95% CI (1.45–4.51)], respectively. Moreover, these PRs were larger for 2021 compared to 2020. Conclusion: During the COVID-19 pandemic, approximately one-fifth of married women who had childbearing intentions before the pandemic decided to postpone pregnancy. They exhibited a deteriorated mental health state. Furthermore, the negative associations were larger in 2021 compared to 2020. Loneliness has negative consequences for both mental and physical health, as well as elevated severe psychological distress and suicidal ideation among those who decided to postpone pregnancy. Therefore, the current results should not be overlooked by society.

Female sex workers (FSWs) are at considerable risk of developing mental disorders due to the potential for violence associated with their work. However, few studies have comprehensively investigated the types of violence and their impact on the mental health of FSWs. Using data collected from 403 FSWs in Yangon, Myanmar, we investigated how various types of violence perpetrated by clients, employers, and partners affect the severity of mental disorders (anxiety and depression) among FSWs. Our results indicate that economic violence perpetrated by clients and threats of violence from partners induce severe symptoms of anxiety and depression. Furthermore, sexual and economic violence perpetrated by employers results in severe symptoms of anxiety.

This paper explores the heterogeneous impact of a rural road improvement project on the economic activities and living standards of households in Morocco. Road pavement improvements are expected to promote better market access, encourage the transformation of traditional agricultural activities, and create opportunities for new economic activities. However, benefits may not extend evenly across different groups, and the distributional consequences call for careful empirical investigation. We employ a difference-in-differences (DID) estimation using a household-level panel dataset collected under a quasi-experimental setting in the 2010s. We classify households into three groups based on asset holdings (rich, middle, and poor). We provide several new findings. First, there was no significant transformation of agricultural production or sales for all groups. Second, rich households increased hired agricultural labor and began paid employment while middle households started new family businesses. Poor households, however, did not enjoy these new employment opportunities except for a marginal increase in family businesses. Third, due to shifts in employment, the rural road renewal project improved household consumption 3%–4% annually for rich and middle households, an impact not clearly seen among poor households. Thus, our findings show that the economic benefits of rural road improvement might not be well-inclusive.

Using data collected on female sex workers (FSWs) in Yangon, Myanmar, we compare the prices of sexual services offered to investigate whether prices are associated with the place where they find clients—after controlling for FSW and client characteristics and types of services provided. Compared with FSWs in brothels, workers who find clients online charge 62 per cent higher prices, while those in massage parlours charge 39 per cent lower prices. In addition, we find evidence that suggests street-based FSWs earn less than those in brothels. No price differentials are observed among FSWs finding clients in karaoke clubs and in brothels. These findings imply worksites play a vital role in determining the price of sex services in Yangon. We further investigate why these place-based price differentials arise. We describe the plausible characteristics of the price negotiation process, including the matching process and client information, and discuss how these work to yield place-based price differentials at various worksites.

We examine the returns to test scores from the 2009 Vietnamese National Entrance Examination to University (NEEU) of individuals born in 1991. We investigate their labour outcomes in terms of hourly wage and employment measured in 2018 or 2020. We find that a one standard deviation increase in the standardized test score on the NEEU is associated with a 9% increase in wage rate 9–11 years later. The results also suggest that mathematics test scores have a significant correlation with labour outcomes in the long run.

Commercial sex is a prevalent but risky profession in many countries, including Myanmar. Although risk attitude is a potentially important factor in determining risky behaviour of female sex workers (FSWs), few studies have explicitly investigated the issue. This is one of the first studies to elicit the risk attitude of FSWs using a simple risk game. We conducted the risk game with FSWs in Yangon, Myanmar, where the average GDP per capita is very low, to study how risk attitude is related with observable characteristics and with risky behaviour related to the use of condoms in the commercial sex market. We found that risk attitude is relatively independent of observable characteristics and the decision to use a condom. However, transaction prices were directly associated with risk attitude.

This paper examines the impact of a rural road improvement project on schooling decisions and youth employment in Morocco. Paved rural roads are expected to reduce travel time and costs, allowing additional school choices and increasing the motivation for youth to enter higher education. On the other hand, immediate earning opportunities created by new connections may encourage youth to seek paid employment. Thus, the impact of rural road improvement on schooling and youth employment warrants empirical investigation. We employ a difference-in-differences estimation using a household-level dataset collected under a quasi-experimental setting. First, we do not observe any positive effect on primary school completion for either sex, but we find a positive and significant effect on secondary school attainment or above for females. Moreover, the higher educational attainment of females is associated with a lower proportion of early marriage. Second, we do not observe any significant effects on self-employment for either sex, but we find a positive and significant effect on wage employment for males, which is pronounced among the better educated. Our findings reveal sharp gendered differences in the impact of the rural road improvement project, with increased motivation towards better education for females and paid work for males.

This paper examines the short-term impact of better access to improved water available at newly built boreholes on children’s health, schooling, and time allocation in rural Zambia. We employed a difference-in-differences estimation using a dataset collected under a quasi-experimental setting. We observed significant effects of better access to improved water sources on the reduced incidence of diarrhea for pre-school children but not for school-age children. We found no significant effect on school attendance. To understand the mechanism behind this pattern, we examined any changes in time use by children who had better access to improved water sources. For girls, particularly those who lived near the boreholes, we found a significant decrease in time spent on schooling and homework and a significant increase in time spent on water-related household chores including fetching water. We did not find any significant changes for boys. Alongside a significant decrease in time spent on water-related chores by female adults, better access to improved water supply shifts the burden of water-related household chores from female adults to girls while the net burden of water collection alone for girls was unchanged.

With the growing digitization of society, there is a need to enhance computational thinking as an indispensable skill for modern daily life. Consequently, computer science education for children at early ages has become increasingly important. This study conducts a randomized controlled trial to examine the impact of the interventions using educational robotics as well as computer-aided mathematics drills (via a “math app”) on students' performance in primary schools in Basra, Iraq. We provide several new empirical findings. First, the short-run impact of robotics-based learning on computational thinking is positive and statistically significant for girls, particularly poor performing girls, but not for boys. Second, the impact on computational thinking is augmented by introducing a math app, further improving computational thinking. Together, these two interventions also enhance general intelligence. Third, the positive impact was still evident more than three months after the interventions for girls who received both computer science and math education, suggesting their complementarity. Our results show that computer science education using educational robots in primary schools is effective in enhancing computational thinking and relevant skills.

This paper investigates the educational impact on fertility caused by the termination of universal primary education (UPE) in Kenya. Although previous studies have used the introduction of UPE as a natural experiment, we focus on a unique policy change, namely, the termination of UPE. By using six waves of the Kenya Demographic and Health Survey (KDHS), our paper presents the statistically significant discontinuity in female years of education at the termination of UPE. The termination of UPE led to a decrease of 0.57 years in of female education. Using a fuzzy regression discontinuity design, we identify the impacts of education on both onset of fertility and total fertility. One additional year of female education delays onset of fertility by 0.67 years and reduces total fertility by 0.21 fewer children by the age of 46 years. As for the mechanism of these changes, we explore three possible pathways: labor participation, knowledge of contraception, and assortative mating.

We quantify the influences of Confucianism on gender inequality in present-day Vietnam. We use the number (or density) of the most successful test takers in the Vietnamese imperial examinations (1075–1919) in a given district as a proxy for mastering the subject of Confucianism. Using an instrumental variable approach based on the historical expansion of Vietnamese territory and distances to the test venues, we consider the effects on labor, health, and educational outcomes for females relative to males. We find that Confucianism has long-lasting negative impacts on gender inequality in all considered aspects. However, the results also suggest that when present-day females pursue more years of schooling, they tend to perform better than males.

This study investigates the long-term causal effects of U.S. bombing missions during the Vietnam War on later economic development in Laos. Following an instrumental variables approach, we use the distance between the centroid of village-level administrative boundaries and heavily bombed targets, namely, the Ho Chi Minh Trail in southern Laos and Xieng Khouang Province in northern Laos, as an instrument for the intensity of U.S. bombing missions. We use three datasets of mean nighttime light intensity (1992, 2005, and 2013) and two datasets of population density (1990 and 2005) as outcome variables. The estimation results show no robust long-term effects of U.S. bombing missions on economic development in southern Laos but show negative effects in northern Laos, even 40 years after the war. We also found that the results do not necessarily support the conditional convergence hypothesis within a given country, although this result could be unique to Laos.

Using commune-level panel data for 11 years, we investigate whether there is a relationship between toilet facilities at primary and lower secondary schools and school enrollment rates in Cambodia. We differentiate toilet facilities by type (improved and unimproved) and by gender. We find that the number of improved toilets at both primary schools and lower secondary schools per boy/girl in the commune is positively associated with the school enrollment rate of boys/girls of the corresponding age range (7–11 or 12–14 years). A positive association between the number of unimproved toilets per boy/girl and the school enrollment rate of boys/girls was found only at the lower secondary-school level, but the association was much weaker than that for improved toilets. These findings suggest that the construction of improved toilet facilities might lead to higher school enrollment rates.

Our study investigates how the legacies of Vietnamese imperial elites continue to affect top-ranking politicians in Vietnam. The study compares a list of people who passed the imperial examination (1075–1919) at the national level with a list of currently active top-ranking politicians in Vietnam (1930–2022) by matching their home districts. Using an instrumental variable approach, we find that those living in the same home districts as imperial elites are more likely to be top-ranking communists. Possible mechanisms for these strong and persistent legacies based on home district connections include a historical culture of striving to reach the upper echelons of Vietnamese society, a belief in meritocracy, and using graduate degrees to signal one's talent.

Background: Betel quid is more widely consumed than tobacco in Myanmar. It brings adverse health effects regardless of whether it contains tobacco; however, Myanmar has no clear prevention strategy. This study aims to show a broader picture of the prevalence of betel quid chewing and the observable characteristics of its consumers in Myanmar by comparing it to tobacco usage. Methods: This study used the 2015-2016 Myanmar Demographic and Health Survey data. First, we identified characteristics of betel quid consumers by a logit model. Next, we focused on exploring who would be likely to become heavy users, conditioned on being a betel quid consumer by controlling for possible sample selection bias. Results: We found differences in characteristics for betel chewers and tobacco smokers, and for betel quid users and heavy users. Conclusion: These results suggest that betel quid consumption should be regulated by a specific prevention strategy rather than by Myanmar's existing tobacco prevention strategy.

We investigated the long-term effects of birthplace favoritism by top-ranking politicians on the quality of education in Vietnam. We used over 1 million test scores from the 2009 and 2014 Vietnamese national university entrance examinations. We examined both the different timing of political terms and the total years of birthplace favoritism. Using the school fixed effects, we found that birthplace favoritism did not have any significant impacts, regardless of the timing and duration of such favoritism. We did not find evidence for such impacts in the distribution of test scores either. The results also suggest that national entrance examinations were unaffected by birthplace favoritism up to 2014.

Background and Aims: Owing to the high mortality rates associated with cervical and breast cancers, increasing screening uptake is a priority. However, the current policy lacks consideration for sexual and gender minorities (SGMs). This study aimed to examine whether SGM women have lower take-up rates of these female-organ-specific cancers than non-SGM women by investigating the difference in screening frequency between them. Additionally, colorectal cancer screening was used as another outcome to determine whether the results were unique to female-organ-specific cancers. Methods: This cross-sectional study was conducted using a nationwide online survey in 2023. Information from women aged 20–69 years was used, with a sample size of 12,305, including 1371 SGM and 10,934 non-SGM individuals. As an outcome variable, the careening take-up of cervical and breast cancers was used, sex-specific cancer and being screened in Obstetrics and Gynecology, colorectal cancer, which is non-sex specific, and the screening is conducted at home. Results: Considering demographic characteristics and socioeconomic status as constants, a lower likelihood of screening for cervical and breast cancer was observed in SGM women than in non-SGM women (odds ratio [OR] 0.78; 95% confidence interval [CI] 0.69–0.88 for cervical cancer, and OR 0.77; 95% CI 0.64–0.93 for breast cancer). No difference was found between SGM and non-SGM women in colorectal cancer screening (OR 0.96; 95% CI 0.80–1.16). Conclusion: This study highlights the sexual orientation and gender identity gap in the frequency of cervical and breast cancer screenings but not in colorectal cancer screenings. This study highlights the potential barriers faced by SGM women, emphasizing the importance of raising awareness of the unique healthcare challenges, particularly concerning female-organ-specific cancers.