This is a summary of my past research. Please go here for a description of my current research.

I received my BS in History and Engineering & Applied Science from Caltech and my MA and PhD in Sociology and Demography from the University of Pennsylvania.

I started out at Caltech planning to double-major in Electrical Engineering and History, the latter with an emphasis on China, but over time my emphasis shifted from engineering to China. I have a separate page where I discuss the origin of my interest in China, and summarize my experiences there. I have also written a somewhat long-winded reminisce and reflection about my time at Caltech.

In my sophomore year at Caltech, I began working as a research assistant for James Lee, who at the time was an Assistant Professor of History an Caltech. This was the beginning of a collaboration on the study of inequality, family organization, and demographic behavior in historical China that continues to this day. At the time, James needed someone with expertise in database programming to help manage the Daoyi household register data he was collecting for what became our book Fate and Fortune. This was an exciting opportunity for me because it allowed me to apply expertise I had developed in high school to work related to what at the time was a hobby interest, China.  My first trip to China came at the end of my sophomore year in summer 1987, when I joined James on a research trip to Beijing and Shenyang.  In Beijing, we stayed at Peking University and carried out research in the No. 1 Historical Archives.  In Shenyang, we stayed at Liaoning University, and visited the Provincial Archives as well as Daoyi.

By my senior year, I decided to pursue a PhD in demography and sociology and eventually an academic career focused on the study of China. In consultation with James Lee and others, I had decided that demography, and quantitative sociology more generally, offered the best opportunity to combine my technical training and expertise and training with my interest in China.

For my PhD dissertation at the University of Pennsylvania, I reconstructed mortality trends in Beijing from the 17th century to the present by combining data from multiple historical and contemporary sources. I showed that death rates in Beijing fell dramatically in the early part of the 20th century because of basic improvements in public health, well before the better known nationwide mortality decline that took place after 1949.

While still a graduate student, I became involved in what would become the Eurasia Project, which is still ongoing, nearly twenty years later. The first meeting I attended was in Kyoto in 1994.  The Eurasia Project is an international and interdisciplinary collaboration that seeks to examine relationships between economic and community context, household organization, and individual demographic behavior in Europe and Asia through comparative analysis of population databases constructed from 18th and 19th century Belgium, Italy, Sweden, Japan and China.  We produced three comparative volumes, Life Under Pressure, Prudence and Pressure, and Similarity in Difference. The first focuses on economic conditions, household organization, and mortality.  The second focuses on fertility.  The third volume, devoted to a comparative study of marriage, was published by MIT Press in 2014.

I joined the UCLA Department of Sociology in 1996 as an assistant professor. I was promoted to associate professor in 2002 and full professor in 2005. I served as Vice-Chair and Director of Graduate Studies for the Department of Sociology from 2002 to 2005. I spent a sabbatical from 2005 to 2006 at the Population Studies Center of the University of Michigan.

For our studies of inequality, family, and demographic organization in northeast China, James Lee and I constructed databases from eighteenth and nineteenth century population registers, the China Multigenerational Panel Datasets (CMGPD). We have released the first of these, the CMGPD-Liaoning, publicly at the Inter-university Consortium for Political and Social Research (ICPSR) with support from the National Institute of Child Health and Human Development (NICHD) with funds from R01 HD057175-01A1 (Lee/Leonard PI). This database comprises 1.5 million observations of more than 250,000 people in several hundred Liaoning villages from 1749 to 1909. A key feature of these data is that through automated record linkage of kin, we have been able to sort the individuals in the database into approximately 1000 distinct descent groups defined by common descent from a founder, allowing for the use of the descent group as a unit of analysis.

With support from NICHD 1R01HD070985-01 (Campbell PI), and in collaboration with Shuang Chen at the University of Iowa, we have released a database we constructed for Shuangcheng county in Heilongjiang province in northeast China, the CMGPD-Shuangcheng.  The population is very different from the one in Liaoning.  It consists of settlers who arrived in the area earlier in the nineteenth century along with their descendants.  The registers cover the population annually from 1865 to 1911.  Distinguishing features of the dataset include the availability of linked landholding registers, and a much richer set of variables describing social status.

I am active in efforts to promote the use of household register data from various settings in East Asia to carry out comparative studies within that region.  One key focus has been to promote connections among researchers working with East Asian historical household register data.  Towards this end, I convened meetings at Hong Kong University of Science and Technology in September 2010 and at UCLA in August 2011 to bring together scholars working with Chinese, Japanese, and Korean data.  These received support from the UC Pacific Rim Research Program.  At these meetings, researchers introduced their data, presented papers, and we developed plans for coordination for future research on topics such as migration and stratification.  Revised versions of selected papers are currently under review for publication in a special collection at a journal.

I was a faculty affiliate of the UCLA California Center for Population Research (CCPR) since its founding, and served as Associate Director for Training at CCPR from 2006 to 2011. As Associate Director, I was Program Director for the CCPR’s NICHD supported T32 training program in population sciences and demography. From 2009 to 2013, I served as Training Director for an NIGMS supported training program (NIGMS 1T32GM084903-01A1) that Professor Julie Bower in Health Psychology and I established with support from many colleagues in CCPR and Psychology to train behavioral and population science students to conduct research at the interface of the behavioral, biomedical, and population sciences.

In 2013, I moved to the Hong Kong University of Science and Technology. I am now a Professor in the Division of Social Science at the Hong Kong University of Science and Technology. I am also Associate Dean for Research for the School of Humanities and Social Science.

My teaching focuses on graduate courses in statistics and social demography, and undergraduate courses in Chinese society and social demography.