Wikipedia articles 20% more likely to influence legal reasoning of Irish judges, scientists find

Concern raised over ‘reliance’ on online resource by judges and legal staff due to risk of anonymous manipulation

Anonymous legal articles on Wikipedia are 20 per cent more likely to influence the legal reasoning of Irish judges than articles not on the online encyclopedia, according to research by scientists at Maynooth University and two US colleges.

The research team arranged for 150 new Wikipedia legal articles on Irish Supreme Court decisions to be written by law students. Half were randomly chosen to be uploaded where they could be used by legal personnel, including judges, and the rest were kept offline and treated as the control group.

The researchers looked at two measures: whether the cases on Wikipedia were more likely to be cited as precedents by subsequent judicial decisions, and whether the argumentation in court judgments echoed the linguistic content of the new Wikipedia pages.

Their key finding was that getting a Wikipedia article increased a case’s citations by more than 20 per cent. The effect was particularly strong for cases that supported the argument the citing judge was making in their decision, but not the converse.


The increase was bigger for citations by the High Court and mostly absent for citations by the Supreme Court and Court of Appeal. The researchers suggest that indicates Wikipedia is used more by judges or legal assistants with a heavier workload for whom the convenience of the online source is a greater attraction.

The findings are set out in a paper by lead researcher Neil Thompson, of the Massachusetts Institute of Technology; Brian Flanagan, Edana Richardson and Brian McKenzie of Maynooth University; and Xueyun Luo of Cornell University. The paper was published online on Wednesday and a final version will be published next year by Cambridge University Press.

Prof Thompson said the finding that judges or their staff are using Wikipedia is “a much bigger worry if the information they find there is not reliable”.

“The worst outcome would be for a judge’s reliance on Wikipedia to lead them to decide a case differently than they would have if they had read either an expert secondary source or the cited precedent itself. Even without any difference in outcome, however, judges’ reliance on Wikipedia to determine the applicable law undermines the litigant’s expectation that the court’s reasoning is the product of expertise alone.”

Dr Flanagan said a well-resourced litigant could encourage their legal team to anonymously integrate their own analysis of a relevant precedent into a Wikipedia article at an early stage of litigation in the hope of later attracting the attention of the judge or their assistant.

“It’s difficult to quantify the risk of such a practice. But given known trends in online misinformation and the relative openness of Wikipedia’s content to general internet users, it is possible to imagine scenarios in which it might surface.”

Mary Carolan

Mary Carolan

Mary Carolan is the Legal Affairs Correspondent of the Irish Times