Δαφνη Ευτυχια Αρθουρος

"The study relied on a large experiment. Until 2016 users saw tweets only from accounts they followed, shown in reverse chronological order. After launching its algorithm, Twitter kept 1% of users in the old system. This let it measure how often its algorithm served up certain tweets, compared with the 'reverse-chron' method.

"In April-August 2020 the authors used this approach on 3,634 accounts belonging to legislators from 32 political parties. Although they did not detect political bias in the treatment of individual lawmakers, they did find a slant when grouping accounts by party. In all countries but Germany, the algorithm's 'amplification ratio' was lower for members of leftist parties than for members of right-wing ones.

[...]

"In 2019 we studied how Google ranks news stories, and found that accuracy, not ideology, explained its rankings. This is also true of Twitter. However, whereas Google gave higher rankings to more reliable sites, we found that Twitter boosted the least reliable sources, regardless of their politics. Left-wing sites with poor accuracy scores, like tmz, were amplified more than credible, conservative ones like the Wall Street Journal. ProPublica, a non-profit focused on public-interest investigations, had one of the lowest amplification ratios."

-- from "According to Twitter, Twitter's algorithm favours conservatives", The Economist, 2021-11-13