A new analysis of “unoriginal” writing by the anti-plagiarism site Turnitin finds that college students aren’t much better than high school students at choosing their sources.

A growing number of college presidents and faculty are concerned about student plagiarism in the Internet age. But the questions raised by this analysis go beyond ethics. Wouldn’t professors be disheartened to learn that a significant share of students are harvesting their facts not from an old-fashioned encyclopedia but from Yahoo Answers?

Wikipedia is the most popular source of borrowed text on the Internet in both high school and college, according to the Turnitin analysis of 33 million student papers.

As a reference source, Wikipedia is flawed but defensible. It’s a free online encyclopedia “that anyone can edit.” Anything on the site could be wrong. But it’s so popular, and so well annotated, that oft-viewed pages tend to hew fairly close to the facts.

But take a look at some other popular online destinations for student scholarship.Here are the top sources of borrowed content for high school and college students. (This is not a list of plagiarized sources; the analysis doesn’t consider whether the borrower properly credited the potentially purloined text.)

1. Wikipedia.

2. Yahoo Answers. On this site, as far as I can tell, accuracy is determined by a popular vote. Fact and opinion dwell side by side.

3. Answers.com. This site ranks third for high school students, fourth for college students. By its own admission, the site “marries the best of community-driven questions and answers with hundreds of respected and trusted editorial reference books.” In other words, a student could find high-quality reference material on the site, or information that is not necessarily factual, merely popular.

4. Slideshare. This site ranks third among college students, fifth among high schoolers. I had never heard of it. It appears to house a collection of Powerpoint presentations. I searched “Sioux” and found several scholarly presentations on Sioux Indians, as well as real estate listings and a collection of TV quiz-show questions.

5. Oppapers. This site ranks seventh among high school students, fifth among college students. It is one of several sites that offer free research papers. It’s marketed as an “idea encyclopedia,” but clearly this is a place where students can save the effort of actually writing a paper.