All right, in this module, I'm going to introduce the China Health and Retirement Longitudinal Study. This is an important study of the aging population in China. And is going to yield a lot of insight into the dynamics of aging in this very large and important population. The China Health and Retirement Longitudinal Study was launched in 2007. It was based on the Health and Retirement Study that's been carried out for some time in the United States. The English Longitudinal Study of Aging, the Survey of Health, Aging and Retirement in Europe, SHARE, as well as other aging surveys being conducted in other settings. It seeks to survey a nationally representative sample of Chinese residents ages 45 and older. The people carrying out this survey sought to include people we don't normally think of as elderly because we want to, or they want to be able to follow people that are currently in late middle age as they reach retirement age and then going to old age. The response rate of the pilot survey that was conducted by the investigators was extremely high, 85%. And that bodes well for the future success of the survey. There have already 300 published and working papers produced using data from CHARLS as well as 5 book chapters. So this is a lot of outputs for a relatively new survey. When the survey was launched in 2007, it was launched by the National School of Development and the Institute of Social Science Survey at Peking University. And they also had overseas collaborators who had experience with aging surveys in other contexts or longitudinal studies in other contexts. There have already been a number of ways. So the first pilot study was in 2008. Then in 2011, there was the first actual wave for CHARLS, the baseline survey that collected a lot of basic information that would be used as the respondents were followed forward in time. Then in 2012, there was a second wave of the pilot. And then in 2013, a second wave of the full survey. Then in 2014, a third wave, which included a life history. And these are all being combined to produce a harmonized CHARLS. So, the data is, according to the goals of the investigators, to be made public one year after the end of data collection, and so a lot of people are already using the CHARLS data to study the aging population in China. The data have a number of important characteristics, nationally representative as we mentioned earlier. They achieve national representativeness through multi-stage stratified probability proportional to size sampling, which we discussed in a previous lecture on sampling. So this allowed them to obtain a nationally representative sample while it still at the same time remaining within a reasonable budget. Individuals are to be followed up every two years. It includes a sample of the Chinese residents, as we mentioned earlier aged 45 and older. The baseline survey collected information on 10,000 households and 17,500 individuals. And if you want to learn more you can go to their website at Peking University. The CHARLS includes a number of modules on almost every aspect related to aging. So we have demographics, family structures and transfers, health status and functioning, biomarkers, health care and insurance, work, retirement and pension, income and consumption, assets, individual and household, as well as community level information. Well, there are a number of related surveys that inspired the CHARLS, and I'll mention a few of them. One is the Health and Retirement Study from the University of Michigan, the English Longitudinal Study of Ageing, Survey of Health and Retirement in Europe, which I mentioned earlier. We have the URLs are all right here. Then, there's the Japanese Study on Aging and Retirement. The Study on Global Ageing and Adult Health. And, also, you may want to look at the Global Aging Data Repository for more information or more data related to the study of aging. So, overall there's enormous amount of data, not just in China, but around the world, available for the study of aging. And we can look for not only a better understanding of China, but a better understanding globally of aging in a comparative perspective.