The coronavirus pandemic’s impact on the travel patterns of migrant workers – making it more difficult to count them – may have played a key role in Beijing’s decision to delay the release of its once-a-decade population census, according to a veteran demographer who has closely studied China’s previous census practises. The postponement of China’s 2020 census data release – first from early April to late April, and then to an indefinite date in the future – has raised suspicions in some quarters that the government was intervening to cover up problems with the data, though there has been no evidence to support this speculation. Every day since the first delay, netizens have posted a myriad of satirical comments on the official social media account of the National Bureau of Statistics (NBS), calling for it to release the data. “I come here every day to check in on the census. I’ve never even been this diligent when it comes to running or taking medicine,” said one popular comment on Weibo, China’s version of Twitter. Cai Yong, who has studied China’s demographics for years, said that while a lot of attention is being paid to China’s falling fertility rate, it is unlikely to be the biggest reason behind the delay. What is China’s 2020 census, and why is it important? “My personal feeling is the delay has more to do with migration than fertility,” said Cai, an associate professor of sociology at the University of North Carolina, Chapel Hill. “While there has been a great deal of attention on fertility in China, the fact is that we all know the birth number will be low. “The NBS has a set of well-developed procedures to make necessary fertility/birth adjustments, as it has been doing for the past few decades. However, Covid and related travel restrictions likely disrupted the usual labour-migration patterns.” During the pandemic, many migrant workers were forced to stay in their hometowns because of travel restrictions. Last year, the number of migrant workers in China fell 1.8 per cent from a year earlier to 285 million, NBS data shows. This was the first decline since 2008. “I suspect that the NBS has to develop a new method/algorithm to balance the population estimates across provinces and regions,” Cai said. “It is trickier – just like in the United States, where population by state has direct political ramifications [in apportioning congressional districts], provincial/regional population numbers in China are related to all kinds of statistics used in planning and evaluation.” Failing to meet [the government’s] self-imposed deadline indeed suggests potential data problems. But we all know that modern surveys and censuses are not just simple counting and tabulating Cai Yong, sociology professor In previous censuses, the Chinese government included provincial population figures and their changes over the past decade in its main data release. This data has influenced regional economic planning and the central government’s allocation of resources. The previous census in 2010 showed that six provincial-level jurisdictions – Gansu, Anhui, Guizhou, Sichuan, Hubei and Chongqing – saw their populations decline, marking the first time any province’s population had shrunk since the early 1960s. The losses were entirely attributed to migration, evoking concerns at the time that central China would continue to lose people to better employment opportunities in coastal provinces. “To its credit, the Chinese government has a good record in releasing census numbers and population statistics on time. Failing to meet its self-imposed deadline indeed suggests potential data problems. But we all know that modern surveys and censuses are not just simple counting and tabulating. They require careful checking, cross-examinations and adjustments before official releases,” Cai said. In the past, the under-reporting of infants and children in censuses was a big problem, mainly because of the old one-child policy – a strict system under which many households would not report their extra children to avoid punishment. With the one-child policy having ended in 2016, there should be less incentive to hide children, and so the 2020 census should be better at counting them. Nonetheless, complications may arise. “Even as straightforward as it may seem to be on paper – defining who to count and where – real life is often more complicated. For example, how do you count newborns who were still in hospital,” Cai said, adding that undercounting children has also happened in other countries. That includes the US, whose just-released 2020 census showed the second-slowest decade of population growth since 1790. In China’s previous censuses, demographers also found a large number of missing girls, given the traditional Chinese preference for sons over daughters, which resulted in selective reporting under the one-child policy. This led to a distortion in the population’s male-female ratio. An examination of the 1990 and 2000 censuses showed that more than a quarter of all girls who were unaccounted for in the 1990 census appeared in the 2000 figures. A similar situation also occurred between 2000 and 2010. China population: plan to lift retirement age stokes workers’ anxiety as demographic crisis looms “Each census has its own unique problems due to particular social and political circumstances,” Cai said. China’s 2020 census, for the first time, recorded people’s official ID numbers, which helps prevent people from being counted twice, and the census results were said to be cross-referenced with other databases in spot checks. While some undocumented people will inevitably fall through the cracks, the new approach could at least improve internal consistency, according to Cai. “As I have been telling others, given the Chinese government’s almost total control, if China cannot provide a reasonable counting of its population, most other countries would fail,” he said.