How are encyclopedias cited in academic research? Wikipedia, Britannica, Baidu Baike, and Scholarpedia

Encyclopedias are sometimes cited by scholarly publications, despite concerns about their credibility as sources for academic information. This study investigates trends from 2002 to 2020 in citing two crowdsourced and two expert-based encyclopedias to investigate whether they fit differently into the research landscape: Wikipedia, Britannica, Baidu Baike, and Scholarpedia. This is the first systematic comparison of the uptake of four major encyclopedias within academic research. Scopus searches were used to count the number of documents citing the four encyclopedias in each year. Wikipedia was by far the most cited encyclopedia, with up to 1% of Scopus documents citing it in Computer Science. Citations to Wikipedia increased exponentially until 2010, then slowed down and started to decrease. Both the Britannica and Scholarpedia citation rates were increasing in 2020, however. Disciplinary and national differences include Britannica being popular in Arts and Humanities, Scholarpedia in Neuroscience, and Baidu Baike in Chinese-speaking countries/territories. The results confirm that encyclopedias have minor value for academic research, often for background and definitions, with the most suitable one varying between fields and countries, and with the first evidence that the popularity of crowdsourced encyclopedias may be waning.