Shiko Maruyama joined UTS in December 2013. Shiko completed his PhD at Northwestern University, Evanston, Illinois, USA. His Fields of specialization are Health Economics, Microeconomics, Family Economics, Public Finance, Industrial Organization, and Labour Economics. For more details, please visit Shiko's personal website.
Can supervise: YES
We revisit the causal effect of birthweight. Because variation in birthweight in developed countries primarily stems from variation in gestational age rather than intrauterine growth restriction, we depart from the widely-used twin fixed-effects estimator and employ an instrumental variable - the diagnosis of placenta previa, which provides exogenous variation in gestation length. We find protective effects of additional birthweight against infant mortality and health capital loss, such as cerebral palsy, but in contrast to sibling and twin studies, no strong evidence for non-health long-run outcomes, such as test scores. We also find that short-run birthweight effects have diminished significantly over the decades.
Women have a lower BMI than men in developed countries, yet the opposite is true in developing countries. We call this the gender BMI puzzle and investigate its underlying cause. We begin by studying time trends in Japan, where, consistent with the cross-country puzzle, the BMI of adult women has steadily decreased since the 1950s, whereas the BMI of adult men has steadily increased. We study how changes in energy intake and energy expenditure account for the over-time gender BMI puzzle using the Japanese National Nutrition Survey from 1975 to 2010, which provides nurse-measured height and weight and nutritionist-assisted food records. Because long-term data on energy expenditure do not exist, we calculate energy expenditure using a steady-state body weight model. We then conduct cross-country regression analysis to corroborate what we learn from the Japanese data. We find that both energy intake and energy expenditure have significantly decreased for Japanese adult men and women and that a larger reduction in energy expenditure among men than women accounts for the increasing male-to-female BMI gap. Trends in BMI and energy expenditure vary greatly by occupation, suggesting that a relatively large decrease in physical activity in the workplace among men underlies the gender BMI puzzle. The cross-country analysis supports the generalizability of the findings beyond the Japanese data. Furthermore, the analysis suggests the increasing male-to-female BMI gap is driven not only by a reduction in the energy requirements of physically demanding work but also by weakening occupational gender segregation. No support is found for other explanations, such as increasing female labor force participation, greater female susceptibility to malnutrition in utero, and gender inequality in nutrition in early life.
The westernization of Asian countries has led to the rapid expansion of Western-style fast-food restaurants, which are believed to be fueling an unprecedented rise in body mass in these countries. This study tests this belief using longitudinal data from China. Exploiting the opening of a Western-style fast-food restaurant in a particular community, we conduct a transition analysis to make a more convincing causal interpretation than the standard cross-sectional or fixed-effects approach. Considering several measures of fatness, we find no robust evidence of Western fast food having a substantial effect overall, but there is some indication of effect heterogeneity.
There is a potential free-rider problem when several siblings consider future provision of
care for their elderly parents. Siblings can commit to not providing long-term support by
living far away. If location decisions are made by birth order, older siblings may enjoy a Örstmover
advantage. We study siblingsílocation decisions relative to their parents by estimating a
sequential participation game for US data. We Önd: (1) limited strategic behavior: in two-child
families, more than 92% of children have a dominant strategy; and (2) a non-negligible public
good problem: in families with multiple children, 18.3% more parents would have had at least
one child living nearby had location decisions been made cooperatively
Geographically targeted crime control is a controversial attempt to alleviate crime, which risks the displacement of crime into neighbouring areas. The 2014 Sydney lockout laws have decreased the nightlife economy and violence in the entertainment districts, having displaced them into neighbouring areas. We investigate the effect of the Sydney lockout laws on rental prices in the displacement areas, and find a relatively weak and short‐lived negative effect on small dwellings and a persistent positive effect on large dwellings. Our results indicate the long‐term positive effect of the lockout laws on the land value of surrounding areas, despite reported crime displacement.
Johar, M, Maruyama, S & Nakamura, S 2015, 'Reciprocity in the formation of intergenerational coresidence', Journal of Family and Economic Issues, vol. 36, no. 2, pp. 192-209.View/Download from: Publisher's site
Maruyama, S & Yin, Q 2012, 'The Opportunity Cost of Exercise: Do Higher-Earning Australians Exercise Longer, Harder, or Both?', Health Policy, vol. 106, no. 2, pp. 187-194.View/Download from: Publisher's site
Despite the widely documented benefits of exercise, very little is known about how individuals make the decision on exercise. In particular, the decision on the intensity of exercise has attracted only one US study to date, which tests the hypothesis that individuals shift toward less time-intensive but more physically intensive forms of exercise as their wages increase. In this article, we revisit this hypothesis by employing a more credible empirical framework. Studying Australian data we confirm that higher-income Australians tend to exercise more frequently with a longer duration and a higher intensity of exercise. Exercise regimens individualised based on the behavioural patterns of exercise across socio-economic groups will contribute to the efficiency and efficacy of the exercise promotion.
Informal filial care plays an important role for elderly parents facing health challenges. Ageing, however, exacerbates the burden of filial care because the ratio of older to younger individuals is higher and disabled parents live longer. The well-being of elderly parents is even more insecure in Asian developing countries that are undergoing unprecedented ageing and drastic changes in social norms and values, whereas old-age support systems have yet to be developed. In this paper, we investigate factors that influence cohabitation decision by elderly parents and their adult children using the longitudinal Indonesian Family Life Survey (IFLS). Focusing on new cohabitation in which a parent who lives independently starts to cohabitate with a child, we conduct transition analysis to make a more convincing causal interpretation than the standard cross-sectional approach. We find that, while parental needs are important, cohabitation is influenced to a larger extent by the costs and gains of children. The elderly facing health and economic challenges are at higher risk of not receiving filial support than other elderly individuals.
The U.S. Medicare program has increased its spending on private Medicare plans in anticipation of larger consumer surplus and higher efficiency. To evaluate the welfare consequences of such policy interventions, I develop an empirical model with endogenous entry. Counterfactual simulation reveals the following: subsidizing HMO entry can be justified to enhance national welfare (no excessive entry); the level of price subsidies in 2008, however, is far beyond the optimal level; and the geographic inconsistency between the subsidies and the Medicare fee-for-service costs is another source of inefficiency. Resolving this geographic inconsistency significantly raises national welfare by restructuring entry
Maruyama, S 2009, 'Estimating Sequential-Move Games by a Recursive Conditioning Simulator', UNSW Australian School of Business Research Paper, no. 2009.
Maruyama, S 2009, 'Health care system in Australia - Its unique dual system' in Masako Ii (ed), National health care systems in Asia and Oceania, University of Tokyo Press, Tokyo, Japan, pp. 1-33.
Mu, C & Maruyama, S 2013, 'Salient gender differences in the wage elasticity of General Practitioners', iHEA 9th World Congress on Health Economics, Sydney.
Johar, M & Maruyama, S 2010, 'Intergenerational cohabitation in modern Indonesia: Filial support and dependence', 1st Australasian Workshop on Econometrics and Health Economics, Melbourne.
Maruyama, S 2012, 'Inter Vivos Health Transfers: Final Days of Japanese Elderly Parents'.
Capatina, E, Keane, M & Maruyama, S, 'Socio-economic Disparities in U.S. Healthcare Spending: The Role of Public vs. Private Insurance'.
In the US healthcare system, patients of different socio-economic status (SES) often receive disparate treatment for similar conditions. Prior work documents this phenomenon for particular treatments/conditions, but we take a system-wide view and examine socioeconomic disparities in spending for all medical conditions at the 3-digit ICD-9 level. We also compare SES spending gradients for those covered by private vs. public insurance (Medicare). Using data on adult respondents from the Medical Expenditure Panel Survey 2000-14, we estimate multivariate regressions for individual medical spending (total and out-of-pocket) controlling for medical conditions, demographics, health, and insurance, separately by sex, education, and age. Within age-sex categories, we assess how spending on each condition varies with education (a proxy for SES). In the predominantly privately insured population aged 24-64, system spending for several of the most socially costly conditions is strongly increasing in education (e.g., breast cancer for women and chest symptoms for men). These disparities are not explained by differences in health, insurance status, or ability-to-pay, suggesting they arise due to discrimination. However, we find no positive SES gradients for individuals over 64 covered by the public Medicare program, suggesting that Medicare plays an important role in improving equity.
Johar, M & Maruyama, S, 'Externality and Strategic Interaction in the Location Choice of Siblings under Altruism toward Parents'.
When siblings wish for the wellbeing of their elderly parents, the cost of care giving and long-term commitment creates a free-rider problem among siblings. We estimate a sequential game to investigate externality and strategic interaction among adult siblings regarding their location choice relative to their elderly parents. Using the US Health and Retirement Survey, we find a positive externality and strategic interaction. The first-mover advantage of eldest children and the prisoner's dilemma are likely to exist but their magnitudes are negligible compared with inefficiency in joint utility. Inefficiency is large in a family with an educated, widowed mother and with educated siblings who are younger (relative to parents), married, and similar to each other. Had siblings fully internalized externality and jointly maximized utility sum in 2010, 17% more parents with multiple children would have had a child nearby. Public policies that reduce children's private costs may enhance social welfare.
Johar, M & Maruyama, S, 'Externality and Strategic Interaction in the Location Choice of Siblings under Altruism toward Parents.'.
When siblings wish for the well-being of their elderly parents, the cost of caregiving and long-term commitment creates a free-rider problem among siblings. We estimate a sequential game to investigate externality and strategic interaction among adult siblings regarding their location choice relative to their elderly parents. Using the US Health and Retirement Survey, we find a positive externality and strategic interaction. The first-mover advantage of eldest children and the prisoner's dilemma are likely to exist but their magnitudes are negligible compared with inefficiency in joint utility. Inefficiency is large in a family with an educated, widowed mother and with educated siblings who are younger (relative to parents), married, and similar to each other. Had siblings fully internalized externality and jointly maximized utility sum in 2010, 17\% more parents with multiple children would have had a child nearby. Public policies that reduce children's private costs may enhance social welfare.
Johar, M, Maruyama, S & Nakamura, S, 'Transition to Parent-Child Coresidence: Parental Needs and the Strategic Bequest Motive'.
The strategic bequest motive implies that children may want to live with their parents and provide care for them with the expectation of inheriting a larger portion of their bequest. This paper examines this hypothesis by focusing on the transition to coresidence by elderly Japanese parents and their children using underutilized Japanese panel data. Unlike previous studies, evidence for the bequest motive is generally tenuous. In addition, our use of a two-component mixture logit model identifies the minority group of families that follows the bequest motive and the majority group that does not.