Benjamin Ly Serena

Assistant Professor

Department of Economics,

Copenhagen Business School

bse.eco@cbs.dk 

Research interests: Health Economics, Public Economics, Health Inequality, Mental Health, Applied Microeconometrics

Publications

(With Gordon Dahl (UCSD), Claus Thustrup Kreiner (UCPH) and Torben Heien Nielsen (UCPH))

Abstract

We provide a novel decomposition of changing gaps in life expectancy between rich and poor into differential changes in age-specific mortality rates and differences in “survivability”. Declining age-specific mortality rates increases life expectancy, but the gain is small if the likelihood of living to this age is small (ex-ante survivability) or if the expected remaining lifetime is short (ex-post survivability). Lower survivability of the poor explains half of the recent rise in inequality in the US and the entire rise in Denmark. Declines in cardiovascular mortality benefited rich and poor, but inequality increased because of differences in lifestyle-related survivability.

Abstract

Over the past three decades, many countries have introduced iodized salt policies to eradicate iodine deficiency. Iodine deficiency in utero is detrimental to cognitive ability, but little is known about the consequences of iodine deficiencies after birth. This paper examines the impact of iodine deficiency in adolescence on school performance. I exploit the introduction of iodized salt in Denmark during 1998-2001 as a natural experiment. Combining administrative records on high school grades over a thirty-year period with geographic variation in initial iodine deficiency, I find that salt iodization increases the GPA of students by 6-9 percent of a standard deviation.

(With Claus Thustrup Kreiner (UCPH) and Torben Heien Nielsen (UCPH))

Abstract

This work proposes a method to compute the income gradient in period life expectancy that accounts for income mobility. Using income and mortality records of the Danish population over the period 1980–2013, we validate the method and provide estimates of the income gradient. The period life expectancy of individuals at a certain age, and belonging to a certain income class, is normally computed by using the mortality of older cohorts in the same income class. This approach does not take into account that a substantial fraction of the population moves away from their original income class, which leads to an upward bias in the estimation of the income gradient in life expectancy. For 40-y-olds in the bottom 5% of the income distribution, the risk of dying before age 60 is overestimated by 25%. For the top 5% income class, the risk of dying is underestimated by 20%. By incorporating a classic approach from the social mobility literature, we provide a method that predicts income mobility and future mortality simultaneously. With this method, the association between income and life expectancy is lower throughout the income distribution. Without accounting for income mobility, the estimated difference in life expectancy between persons in percentiles 20 and 80 in the income distribution is 4.6 y for males and 4.1 y for females, while it is only half as big when accounting for mobility. The estimated rise in life-expectancy inequality over time is also halved when accounting for income mobility.


Current research projects

(Previously titled "Revisiting Offsets of Psychotherapy Coverage")

Abstract

Depression and anxiety disorders are leading causes of disability worldwide, with enormous costs to society. Yet, insurance coverage for effective treatments remains limited and many patients are left untreated. This paper studies the effects of scaling up access to psychotherapy on mental health, health care use, and labor market outcomes. I study a 2008 reform of the Danish public health insurance, which introduced 60 percent coverage of the cost of psychotherapy for depression and anxiety patients below the age of 38. Using administrative data covering 1995-2019 and regression discontinuity and difference-in-difference designs, I show that psychotherapy coverage reduces the use of other mental health services, physical health care, and suicide attempts. However, I find no effect on labor market outcomes including employment, sickness benefits, and disability pension receipt. Still, the savings in health care exceed the cost of the policy. This suggests that scaling up access to mental health care is both cost-reducing and welfare-improving.



(With Sonja Settele (UCPH))

Abstract

We study the role of cancer -- the leading cause of death in high income countries -- in driving the income gradient in life expectancy. Based on Danish administrative data, we decompose the overall role of cancer in accounting for income-related inequality in life expectancy into shares accounted for by differences in the incidence of cancer, the timeliness of cancer detection, treatment, comorbidities and finally residual mortality holding all previous factors constant. We find that a higher incidence of cancer and a higher residual mortality of low income patients account for the largest part of the income difference in life years lost. Cancers of the respiratory and of the digestive system are the biggest drivers of inequality and known to be caused by unhealthy behavior. Taken together, our findings suggest that to mitigate inequality in cancer-specific mortality policy makers should focus on promoting healthier lifestyles, whereas early detection and treatment through the Danish health care system are already equal for patients with different incomes.

        (With Paul Bingley (VIVE), Claus Thustrup Kreiner (UCPH)

Abstract

We estimate inequalities in cohort and period life expectancy across income, education, wealth and IQ using Danish administrative data over four decades. Using IQ at 18 as a benchmark measure of innate ability, we document how period life expectancy estimates of the education gradient are biased by trends in education composition and how income and wealth gradients are overestimated due to mobility and reverse causality. We test various solutions proposed by previous literature and show that education gradients based on a relative measure of education bears the closest resemblance to our benchmark results on IQ at age 18. Once compositional differences are accounted for, education gradients provide a more accurate measure of inequality in life expectancy than income and wealth gradients.