The Evidentiary Basis of Wikipedia


In a recent immigration case, the 8th Circuit criticized an immigration judge for relying on Wikipedia in making factual findings. This has spurred a flurry of wrongheaded posts on lawprof blogs, all falling into the trap of claiming that it’s always wrong to cite Wikipedia.

The first issue they miss is that there’s a world of difference between citing Wikipedia as an authority on a matter of law, versus citing it to establish a fact. For legal questions, Wikipedia currently is always wrong; legal authority comes from certain kinds of sources—principally statutes, regulations, and case precedents—and Wikipedia simply has not the authority. It might someday become a respectable secondary source the way that law review articles and treatises can be, but it won’t displace the primary sources themselves.

Things are different on matters of fact. Here, Wikipedia is like any other source that makes claims about the world. It might be right, it might be wrong, and everything else is about assessing its reliability in context. There’s no point in having a categorical rule here; if Wikipedia really is the best source on a point, go ahead and cite to it. Sometimes (indeed often) it may not be the best source, but the reasons people use to argue that it isn’t are the wrong ones.

In evidence terms, for example, the problem can’t purely be one of reliability. As a practical matter, Wikipedia is often right, and seems to be becoming more so over time. It’s also often wrong, but so too are newspapers and other traditional sources. Ultimately this is an empirical question, and plenty of people who dismiss Wikipedia don’t back up their assertions of unreliability with actual evidence of it.

The problem also isn’t one of foundation. People like to point out that “anyone can edit” Wikipedia and that it comes with all sorts of grave disclaimers. They then smile confidently, as though this proved their case that Wikipedia can’t be trusted. But if we start to ask hard questions about the process by which a Wikipedia article is constructed, we should in fairness ask the same hard questions about newspaper articles, entries in other encyclopedias, legal treatises updated every year by students, government reports, and so on. Every document is open to epistemological and sociological inquiry; no document cited for the truth of the matters it asserts is free from all doubt. Wikipedia’s disclaimers simply show it being honest about some of the subjectivity and contingency that haunt all human knowledge-production.

No, the evidentiary reason not to cite Wikipedia is one that’s rarely mentioned: best evidence. There’s almost always a better source to cite. The “no original research” policy comes into play here; Wikipedia strives to present only information that can be found and confirmed elsewhere. Whatever that “elsewhere” is, one generally ought to find it and cite it. Wikipedia’s extensive citations and external references strive to make this process easier; Wikipedia is often the starting point of a good research session, but is rarely the end of one. A rule against citing Wikipedia typically forces writers into seeking out these better sources, and thus it serves the same function as the preference in evidence law for the original document over copies of it.

Of course, the true reason practitioners and students shouldn’t cite Wikipedia is much less noble. Older judges, professors, and lawyers who don’t understand Wikipedia, who subscribe to various fallacies about it, or who may not even have heard of it won’t look kindly on those who do cite it. When you’re at the bottom of the hierarchy, you play by the rules set by those above you, even if the reasoning behind them is shaky. Law is a conservative profession and part of our job as professors is to warn our students about this fact, and warn them well. So don’t cite Wikipedia, kids; you may be right, but they’ll still make fun of you.


This is a great article. I’m pleased to see an informed and reasoned view cutting through the “flurry of wrongheaded posts on lawprof blogs”, as you put it.

Your closing idea—that one of the main problems for the use of Wikipedia is conservatism in the practice of law—is particularly interesting; the idea might apply to other academic disciplines as well.


Great post! I think that dispelling the fallacies both against and for wikipedia. Enjoying the blog, keep up the good work!