Since the 1980s, the sex ratio at birth (SRB) in China has been abnormally high for more than 40 years, and it might take 30 years to return to normal. The 70year SRB transition profoundly affects the population dynamics. Based on the most recent data on SRB, fertility and mortality, this study focuses on the impact of the SRB transition on the age structure in China. The results show that abnormally high SRB has reduced the number of births and thus the population size, thereby has sped up population ageing. Normalizing SRB can alleviate population ageing. Therefore, normalizing SRB could be taken as one of the strategies to actively cope with population ageing, aside from improving gender inequality.

The future is uncertain, and so are the future populations. This uncertainty is a fundamental aspect of population dynamics. It is affected by various factors such as socio-economic development, technological advances, and even cultural change. Understanding demographic uncertainty is essential in policy-making based on population projection. In recent decades, various methods have been developed to describe the uncertainty, including probabilistic forecast. However, such methods have not got enough attention in China, where the population tends to be highly uncertain due to rapid demographic transition and social transformation. In this paper, we investigate the uncertainty and its policy implications. Specifically, we focus on three major aspects of China's population:the number of births, particularly in the era of universal two-child policy, the number of total population, and the target population of regional planning. Overlooking or underestimating demographic uncertainty can lead to misleading projection results for policy makers and the public. We are in need of developing methods for China's population projections.

Based on the Chinese Longitudinal Healthy Longevity Study (CLHLS 2002~2011),this study assesses the age trajectories of the loss of independence in daily living for five cohorts aged 65~69,70~79,80~89,90~99 and 100+ at the 2002 survey,respectively,both at the individual and the population level.Results show that the decline of independence at the population level is more gradual than that at the individual level.A decomposition analysis further reveals that the difference in the pace of decline of independence can be largely attributed to selective mortality and loss to follow up.Moreover,such difference varies across cohorts.For the population as a whole,a longer life expectancy does not necessarily result in a rapid decline of independence.For individuals, however, prolonging lifespan tend to be accompanied with deterioration of independence except for the young old.

 As life expectancy has risen spectacularly since the mid-nineteenth century，and at pres- ent，is high in many countries，increasing attention has been drawn to life disparity-how much lifespans differ among individuals．Life disparity is important because it measures uncertainty in the timing of death. Reducing this uncertainty increases the value of both private and public investments in education and training，and can factor into life course decisions such as retirement planning and the adoption of healthy behavior．The past six decades have witnessed great improvements in life expectancy in China， particularly since the reform and opening up in the late 1970s．Previous studies have well documented the levels，patterns and regional variations of mortality in China．But so far no study has focused on life disparity．This paper aims to fill in this gap with in-depth analysis of the trends in life disparity of China under comprehensive international comparison．We find that the improvement of life disparity that has been made so far in China can partially be attributed to the China-characteristic healthcare system and health-related public policies．

As life expectancy has risen spectacularly since the mid-nineteenth century，and at present，is high in many countries，increasing attention has been drawn to life disparity-how much lifespans differ among individuals．Life disparity is important because it measures uncertainty in the timing of death．Reducing this uncertainty increases the value of both private and public investments in education and training，and can factor into life course decisions such as retirement planning and the adoption of healthy behavior．The past six decades have witnessed great improvements in life expectancy in China， particularly since the reform and opening up in the late 1970s．Previous studies have well documented the levels，patterns and regional variations of mortality in China．But so far no study has focused on life disparity．This paper aims to fill in this gap with in-depth analysis of the trends in life disparity of China under comprehensive international comparison．We find that the improvement of life disparity that has been made so far in China can partially be attributed to the China-characteristic healthcare system and health-related public policies．