Jian-Meng Liu: The cast of thousands behind our data

Jian-Meng Liu discusses the logistics of recording birthrates in a country as large and diverse as China

I am a Chinese epidemiologist. When I entered the field, in 1985, I wanted to contribute to the field of maternal and child health in my country. However, unlike many western nations at the time, China lacked a national information system to collect basic vital statistics. For example, we had no national system of birth certificates that would allow us to do basic work such as documenting the number of births nationwide. Scientists and enlightened government officials knew that we needed to begin to collect data to make progress. Under the auspices of the National Health Commission of China, the Office for National Maternal and Child Health Statistics of China (OnMCHs) was established in 1996 at the Peking University Health Science Center. Our task was daunting: over two thirds of China’s population lived in less developed rural areas where record keeping was non-existent or rudimentary.

We needed to work with local people to create a uniform system of reporting. Thus an information system was born whereby health workers gathered data on maternal and child health at village, township, and county levels. Under this “three-tiered system,” data were collected locally and then progressed upward, from the lowest level of geographic aggregation, until the information finally reached the OnMCHs office in Beijing.

As you can imagine, the logistics were formidable. Initially data were collected on paper and relayed over the telephone. Over time we have moved to an electronic and online data reporting system. Throughout, we worked closely with health workers to explain and standardise data collection and ensure data quality. Over the years data collection procedures have been continuously reinforced. We do this through annual visits to selected geographic areas, from village to provincial level. Following standardized procedures, local health workers also work regularly in their own geographic areas. Over time, births have moved to hospitals (at the time of  writing, over 99% of births in mainland China take place in a hospital). Now we can collect some data directly from facilities. That hospital-derived data forms the County-level Monthly Aggregated Data (CMAD), a leading data source for the work in this week’s report.

Our new research paper published in The BMJ reports on over 67 million births in China between 2014 and 2017. The study draws on two national databases and thousands of people were involved in creating and sustaining the collection of data.

Our paper is authored by faculty at Peking University and scientists at the National Health Commission, along with colleagues in the United States. Reports like this require collaboration among professionals with varying expertise. But the unsung heroes are the health workers and officials who have worked with us over the years to collect data. Without their contributions it would also be impossible to accomplish the work. Thanks to their efforts, after the announcement of the universal 2-child policy, we were able to pull up electronic records and assess the policy’s impact on a national level. In China, nearly 1.4 billion people live in 9.6 million square kilometers of geographical, cultural, and economic diversity. In a nation this vast and complex, it is vital to have the big picture. Thanks to a cast of thousands, we have that picture today.

Jian-Meng Liu, M.D., Ph.D. is a Professor and Director at the Institute of Reproductive and Child Health, Peking University School of Public Health; Office for National Maternal and Child Health Statistics of China, and National Health Commission Key Laboratory of Reproductive Health, Peking University Health Science Center.

Competing interests: See research paper