Why are Chinese researchers less cited by US academics?

Despite the noteworthy growth in quantity and quality of scientific research emanating from China, Chinese-authored articles receive only half the citations from US researchers as non-Chinese authored papers – a situation likely to be exacerbated by current US-China tensions and COVID travel disruptions.

Following its unprecedented rise as an exporter of goods, China has now also overtaken the US as the world’s largest producer of scientific publications.

China’s share of world publications has increased from 5% in 2000 to 26% in 2018, with particularly strong growth in the fields of chemistry, engineering and materials science.

This development has been facilitated by massive research investments by the Chinese government: between 2000 and 2017, the number of Chinese universities increased by 140%, research faculty increased by 69%, and public research funding increased 10-fold, according to the Compilation of Science and Technology Statistics of Higher Education Institutions (CSTS-HEI) produced by the Chinese Ministry of Education.

Putting to one side whether (scientific) quantity might have a quality of its own, interpreting this dramatic increase is difficult. From the standpoint of its impact on the global economy, an important question is whether, beyond its undeniable quantitative importance, Chinese research contributes to pushing the world’s scientific frontier.

Recent empirical findings lend credence to the view that the quality of Chinese research has improved in concert with the number of articles emanating from Chinese research institutions (and researchers). For instance, the incidence of Chinese addresses (and Chinese names) in leading journals, such as Science and Nature, has more than doubled between 2000 and 2016.

‘Citation discount’

These stylised facts notwithstanding, the extent to which Chinese scientific knowledge offers ‘broad shoulders’ for follow-on researchers to stand on remains an open question. In a recent discussion paper, we tackle this question by focusing on chemistry – one of the fields in which China’s growth has been preeminent.

When comparing Chinese and non-Chinese researchers, we find that Chinese-authored articles receive only half the citations from the US. One explanation for this apparent ‘citation discount’ is that Chinese research is of lower quality than that undertaken in other countries. Alternatively, US scientists might discount the importance of Chinese scholarship, compared to research produced elsewhere in the world.

To distinguish between these two explanations, we control for the ‘quality’ of research in multiple stages. We focus on chemistry, a domain where China has a long tradition of excellence. Within chemistry, we focus our analysis on ‘elite scientists’, the top 1% of researchers who have published in the most impactful chemistry journals.

We hand-collected demographic data on the scientists to control for individual characteristics such as education, age and gender, and use coarsened exact matching (CEM) to find articles of comparable quality for each publication by elite Chinese principal investigators (PIs), using a quality indicator that corrects for the particularly large ‘home bias’ of China’s citations.

Finally, we defined the risk set of articles that may be citing the elite researchers’ publications based on topical relatedness.

Our preferred specifications point to a ‘China citation discount’ equal to 28% of the baseline probability of citation: articles written by Chinese PIs receive significantly fewer citations from US scientists than articles written by non-Chinese PIs.

A unique bias

One may wonder whether the Chinese citation discount exists because the emergence of Chinese science is quite recent. However, we find that the discount has been stable over the past two decades.

Another question is whether China’s experience is unique, or whether other countries suffer from the same bias. Among the top chemistry nations (by number of publications in our sample), no other country experiences a citation discount from the US; instead, Switzerland and Germany exhibit small citation premia.

Due to the relatively high frequency of retraction scandals that have afflicted Chinese scientific teams, we speculate that non-Chinese scientists could deem knowledge and ideas that originate in China to be less reliable than those originating in other countries, leading researchers to cite Chinese research less, even when it would appear equally fruitful.

However, we find that a negative perceived quality of Chinese research does not explain the discount, as it exists in both subfields where scientific retractions are common and where they are rare.

Another explanation could be animus against Chinese researchers. However, the bias is specific to PIs working in China, and not present for PIs with Chinese names who undertake their research in other countries.

Yet another explanation for the discount could be that Chinese researchers concentrate in subfields that are less common in the US. Using an algorithm that models topical similarity across scientific papers, we find evidence that this discount is not a mere reflection of clustering of Chinese researchers in particular subfields that are less likely to be cited by US scientists.

The role of networks

Finally, we test whether strong networks of Chinese PIs help Chinese articles overcome the citation discount. In the past decade, China has continuously expanded global collaboration and communication by funding students’ graduate studies abroad and facilitating Chinese scholars’ participation in international collaboration through the funding of shorter-term stays in frontier countries.

Attendance of international conferences increased almost eight-fold during the same period. Scientists holding overseas degrees account for 37% of the total number of members of Chinese Academies of Sciences and Engineering elected between 1955 and 2009.

In fact, we find that Chinese researchers with unusually deep networks in the US appear to be able to overcome, at least in part, the citation discount: the discount is halved for Chinese researchers who received at least some of their scientific training in the US. Interestingly, it is also not present for US cities with Chinese names.

This suggests that US-based researchers who have ethnic roots in China help diffuse Chinese research to the US. This could also mean that Chinese researchers have access to ethnic-Chinese researchers in the US in their network, but not to other US researchers.

Is the China citation discount likely to be a transitory phenomenon? The Chinese citation discount has proven fairly stable over the past two decades. If awareness and networking are the explanations, current US-China tensions, as well as the disruption of scientific travel induced by the COVID-19 pandemic, might further solidify the lower awareness of foreign citers vis-à-vis research produced in China.

Pierre Azoulay is the International Programs Professor of Management at the MIT Sloan School of Management, and a research associate at the National Bureau of Economic Research; Shumin Qiu is based at East China University of Science and Technology, China, and Claudia Steinwender is Professor of Innovation and International Trade at Ludwig-Maximilians-Universität München, Germany. This article was first published on LSE Blog and summarises “Who stands on the shoulders of Chinese (scientific) giants? Evidence from Chemistry” by Pierre Azoulay, Shumin Qiu and Claudia Steinwender, CEP Discussion Paper No. 1904. The content generated on the LSE Blog gives the views and opinions of the authors and does not reflect the views and opinions of the Impact of Social Science blog, nor of the London School of Economics and Political Science.