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Working Papers


Qian Lu, Katja Hanewald and Xiaojun Wang

Abstract: China has experienced large improvements in mortality rates, but there remain substantial variations at the provincial level. This paper develops new models to project mortality at both the national and provincial levels in China. We propose two models in a Bayesian hierarchical framework based on principal components and a random walk process, and compile a new comprehensive database containing mortality data for 31 provinces over the period 1982–2010. The baseline two-level model with a national–province hierarchy allows for information pooling across provinces, common national factors and consistency conditions. The extended three-level model with a national–region–province hierarchy pools information in the region and also allows for common factors within the region. Both models provide good estimates and reasonable forecasts for China and its provinces. The baseline two-level model provides good fit and reasonable forecasts with equal width intervals for the provinces. The three-level model has a better fit with a lower deviance information criterion and provides forecast intervals reflecting regional uncertainty. The sensitivity analyses show that the forecasts are robust when changing the trend assumptions and regional groups.

Keywords: Mortality modelling, Bayesian framework, Hierarchical models, Coherent mortality projection, China

Elderly couple enjoying life

Sisi Yang and Katja Hanewald

Abstract: The Chinese government has launched a series of health reforms to establish universal health insurance coverage, particularly for vulnerable groups, including older adults. However, the current public health insurance system is highly fragmented, consisting of different programs with different levels of premiums and benefits. We analyse whether the universal health insurance system increases the life satisfaction of middle-aged and older Chinese people and to what extent the type of health insurance affects the life satisfaction of this group. Our study is based on data from the China Health and Retirement Longitudinal Study, a nationally representative longitudinal survey of Chinese aged 45 and above, in 2011, 2013, and 2015. We find that the life satisfaction of middle-aged and older adults does not depend on having any health insurance coverage but varies with the type of health insurance coverage, controlling for potential confounding variables such as health status, occupation, hukou status, education, and other demographic variables. Individuals covered by the most generous program, the Government Medical Insurance, reported a higher life satisfaction. In comparison, individuals covered by the Urban Employee Medical Insurance, the Urban Resident Medical Insurance, and the New Rural Cooperative Scheme reported a lower life satisfaction by 0.155, 0.106, and 0.112 standard deviations, respectively. Our results suggest that establishing a more equitable health insurance system should be the next step in health reforms in China.

Keywords: Life satisfaction, Health insurance, Older adults, Health, China

Elderly couple enjoying life

Kevin Krahe, Michael Sherris, Andrés M. Villegas and Jonathan Ziveyi

Abstract: We develop and assess a value-based longevity index that closely tracks the value of longevity-linked liabilities with the potential to signicantly lower the costs and improve the efficiency of index-based longevity hedging techniques relative to standard mortality rate indices, currently referenced in financial markets. As the US is one of the largest countries in terms of market potential for such an index, we use US economic and population data to demonstrate that hedging with our proposed index generates a material reduction in basis risk relative to indices based purely on mortality rates. This is aided by the use of a multi-population continuous-time affine mortality model and a dynamic Nelson-Siegel model for interest rates. We allow both interest rate and ination risks to impact the value of longevity-linked liabilities in our longevity risk hedging. We also bridge the gap between continuous-time and discrete-time multi-population mortality models and show that the continuous-time models are as effective in hedging liabilities as the often used discrete-time models, while being more familiar to nancial market participants.

Keywords: Value-based longevity index, longevity risk, interest rate risk, inflation risk, longevity basis risk, longevity hedging

Michael Sherris

Zhiping Huang, Michael Sherris, Andrés M Villegas and Jonathan Ziveyi

Abstract: This paper assesses and compares multi-factor continuous time ane mortality models applied to age-cohort mortality curves that are well suited for theoretical and practical application in nance and insurance. Models based on Gaussian distributed mortality rates, as well as the Cox-Ingersoll-Ross (CIR) process allowing for Gamma distributed mortality rates, are compared, also quantifying the probability of negative rates in the Gaussian models. In particular, we introduce the Gaussian Arbitrage-Free Nelson-Siegel (AFNS) mortality model incorporating level, slope and curvature factors. The models have appealing features including ecient estimation and computation. We estimate models using age-cohort data to capture cohort eects more eectively and in order to explain the variability in cohort mortality curves in the continuous time framework. The models allow for Poisson variation in the model estimation using the Kalman lter. The ane mortality models facilitate the derivation of closed-form survivor curves allowing for ecient valuation of mortality-linked claims. The models can also incorporate factor dependence allowing for age-dependence in the mortality curves. Importantly we show that the Gaussian independent factor AFNS model performs very well in explaining and forecasting cohort mortality.

Keywords: mortality models, continuous time, cohort curve, affine rates, Kalman filter

media 2019

Shuanglan Li, Héloïse Labit Hardy, Michael Sherris, Andrés M. Villegas

Abstract: Pooled annuity products, where the participants share systematic and idiosyncratic mortality risks as well as investment returns and risk, provide an attractive and effective alternative to traditional guaranteed life annuity products. While longevity risk sharing in pooled annuities has received recent attention, incorporating investment risk beyond fixed interest returns is relatively unexplored. Incorporating equity investments has the potential to increase expected annuity payments at the expense of higher variability. We propose and assess a strategy for incorporating equity investments along with managed-volatility for pooled annuity funds. We show how the managed volatility strategy improves investment performance, while reducing pooled annuity income volatility and downside risk, as well as an investment strategy that reduces exposure to investment risk over time. We quantify the impact of pool size when equity investments are included, showing how these products are viable with relatively small pool sizes.

Keywords: pooled annuity, equity investment, managed volatility, longevity risk 


Michael Sherris and Pengyu Wei

Abstract: This paper proposes a multi-state model of both functional disability and health status in the presence of systematic trend and uncertainty. We classify each individual observation along two dimensions: health status (other than disability) and disability and use the multi-state latent factor intensity (MLFI) model to estimate the transitions rates. The model is then used to calculate (healthy) life expectancy and price a variety of insurance products. We illustrate the importance of various factors and quantify the potential losses from model misspecification. Our results suggest that insurers should pay great attention to health status, trend, and systematic uncertainty in disability/mortality modeling and insurance pricing. We also find that integrating LTC insurance with life annuity can help to reduce the systematic uncertainties.

Keywords: functional disability; health status; trend; systematic uncertainty


Demographic and technological changes are two megatrends set to transform labour markets around the world. These shifts are already under way and are expected to accelerate, particularly in East and South East Asia, which is home to the world’s oldest and fastest ageing societies and a region with an enviable pace of economic development.

Elderly couple enjoying life

Katja Hanewald, Ruo Jia and Zining Liu

Abstract: This paper studies income inequality in old age and its development over the life cycle. We develop a theoretical framework and a new empirical method to show that income is more unequally distributed in old age than in working age. We combine the regression-based inequality decomposition method and the three-step mediating effect test to analyze the transmission of income inequality from initial socioeconomic differences to income inequality in old age. Our study is based on a panel of over 4,000 old households from the China Health and Nutrition Survey
during 1991-2015. We find that the urban-rural gap and educational inequality are the primary causes of old-age income inequality. The effect of the urban-rural gap is partially mediated by educational inequality. Inequality accumulates with age and is reinforced in old age by the Chinese public pension system, which is fragmented by occupational sector.

Keywords: Inequality; Decomposition; Urban-rural gap; Pensions; China

taxation of pension

George Smyrnis, Hazel Bateman, Isabella Dobrescu, Ben Newell and Susan Thorp.

Abstract: The implications of current balance information for retirement provision are considerably difficult to grasp or anticipate. We study how balance and/or income projections motivate the voluntary savings intentions of pension plan participants over a sequence of ten choices. To this effect, we collect savings intentions from 1,615 respondents aged 25-57 years via an online experimental survey that compares four different formats for retirement account information. The formats are (i) current balance; (ii) current balance and projected retirement balance; (iii) current balance and projected retirement income; and (iv) current balance, projected retirement balance and retirement income. Regardless of information format, merely inviting plan participants to top up their retirement account prompts substantial increases in savings, especially among older respondents. At the first choice round, the income projection triggers marginally more voluntary saving intentions than the lump sum projection alone. However at both the first choice and over sequential choices, the combination of balance and income projections is what matters most. Furthermore, even though older respondents save at a higher level across all treatments, younger respondents are more sensitive to income balance projections than the older survey respondents.