While Gelman (Columbia--Statistics) (and Liebowitz) approaches the issue of trends in co-authorship from the perspective of economists in this post, the cost-benefit issues incident to co-authorship carry over to legal scholars as well. While the norm in legal scholarship tilts away from co-authorship, this norm is evolving in real-time. Indeed, the increase in empirical legal scholarship contributes to this evolution. On the co-authorship question, Gelman is comparatively bullish: "I [Gelman] have a different perspective in that I think even a small collaboration by a coauthor can make an article or book much stronger. Given that this seems to hold in statistics, where we publish dozens of papers a year, I’d think it would be even more the case in economics, where researchers take years to publish a single article."