In the common law tradition, legal decisions are supposed to be grounded in both statute and precedent, with legal training guiding practitioners on the most important and relevant touchstones. But actors in the legal system are also human, with the failings and foibles seen throughout society. This may lead them to take methodological shortcuts, even to relying on unknown internet users for determinations of a legal source's relevance. In this chapter, we investigate the influence on legal judgments of a pervasive but unauthoritative source of legal knowledge: Wikipedia. Using the first randomized field experiment ever undertaken in this area—the gold standard for identifying causal effects—we show that Wikipedia shapes judicial behavior. Wikipedia articles on decided cases, written by law students, guide both the decisions that judges cite as precedents and the textual content of their written opinions. The information and legal analysis offered on Wikipedia led judges to cite the relevant legal cases more often and to talk about them in ways comparable to how the Wikipedia authors had framed them. Collectively, our study provides clear empirical evidence of a new form of influence on judges' application of the law—easily accessible, user-generated online content. Because such content is not authoritative, our analysis reveals a policy gap: if easily accessible analysis of legal questions is already being relied on, it behooves the legal community to accelerate efforts to ensure that such analysis is both comprehensive and expert.

This paper investigates the effects of seeing ideas presented in-person when they are easily accessible online. Presentations may increase the diffusion of ideas intentionally (when one attends the presentation of an idea of interest) and serendipitously (when one sees other ideas presented in the same session). We measure these effects in the context of 25 computer science conferences using data from the scheduling application Confer, which lets users browse papers, Like those of interest, and receive schedules of their presentations. We address endogeneity concerns in presentation attendance by exploiting scheduling conflicts: when a user Likes multiple papers that are presented at the same time, she cannot see them both, potentially affecting their diffusion. Estimates show that being able to see presentations increases citing of Liked papers within two years by 1.5 percentage points (62.5% boost over the baseline citation rate). Attention to Liked papers also spills over to non-Liked papers in the same session, increasing their citing by 0.5 percentage points (125% boost), and this serendipitous diffusion represents 30.5% of the total effect. Both diffusion types were concentrated among papers semantically close to an attendee's prior work, suggesting that there are inefficiencies in finding related research that conferences help overcome. Overall, even when ideas are easily accessible online, in-person presentations substantially increase diffusion, much of it serendipitous.

This article draws on qualitative student feedback and lecturer experience to provide a guide for educators who are interested in creating Wikipedia article-based assignments. Using legal cases as an example, this article details how these assignments can encourage students to deepen their understanding of a topic and consider how knowledge can be communicated effectively. In particular, this article focuses on how educators outside of the United States and Canada can navigate Wikipedia's bureaucracy and how they and their students can contribute information of relevance to smaller jurisdictions on a publicly-accessible repository. This article begins by addressing concerns that educators may have with student use of Wikipedia, while highlighting pedagogical benefits for students who write Wikipedia articles. It goes on to provide a guide for educators who want to create a Wikipedia article writing assignment – in particular, the preparatory steps required to make the assignment effective, how to support students in their writing journey, and how to better ensure that student-authored articles remain available on Wikipedia. This article concludes by encouraging educators to consider using Wikipedia as an educational tool, and to teach their students how they can use Wikipedia article writing to contribute to public knowledge.