User-Generated Content Shapes Judicial Reasoning: Evidence From a Randomized Control Trial on Wikipedia

Abstract

Legal professionals have access to many different sources of knowledge, including user-generated Wikipedia articles that summarize previous judicial decisions (i.e., precedents). While these Wikipedia articles are easily accessible, they have unknown provenance and reliability and therefore using them in professional settings is problematic. Nevertheless, Wikipedia articles influence legal judgments, as we show using a randomized control trial.

We find that the presence of a Wikipedia article about Irish Supreme Court decisions makes it meaningfully more likely that the corresponding case will be cited as a precedent by judges in subsequent decisions. The language used in the Wikipedia article also influences the language used in judgments. These effects are only present for citations by the High Court, not for the higher levels of the judiciary (Court of Appeal and Supreme Court). Since the High Court faces higher caseloads, this may indicate that settings with greater time pressures encourage greater reliance on Wikipedia.

Our results add to the growing recognition that Wikipedia and other frequently-accessed sources of user-generated content have profound effects on important social outcomes. Greater attention should therefore be paid to ensuring that they contain the highest quality of information.

Keywords: Courts, Wikipedia, randomised control trial, media, user-generated content