“Google & others are suppressing voices of Conservatives”, tweeted Donald Trump in 2018. “They are controlling what we can & cannot see.” The president’s charges of bias are often dubious. But many people worry about algorithms absorbing human prejudices. Robert Epstein, an academic, has compiled data that show Google suggesting more positive terms when users type “Hillary Clinton” than when they look up Mr Trump. pj Media, a conservative blog, claims that liberal sites get 96% of results for “Trump” on Google’s news page, a compilation of links to recent articles.
Google says that the 10,000 human evaluators who rate sources for its search engine assess “expertise” and “trustworthiness” but not ideology. Web-traffic figures support this defence. Sites with high scores from fact-checking groups, whose judgments probably resemble Google’s, draw larger shares of their visitors from search engines than sites with low scores do. Factually inaccurate sources also tend to have strong left- or right-wing slants.