I actually had planned a different post about plagiarism. Well, more about citation than anything. Helping someone with a paper recently put in perspective to me how important it is to stress to reason why citing your sources is important, what "research" means, and, really, what authorship and ideas mean (if that makes any sense). But, now I'm going to talk about me and my sources.
For my stratification class, we have to submit the final paper in hard copy as well as online, to turnitin.com, a site that checks for the direct use of someone else's words (a very limited definition of plagiarism, obviously, but it would be hard to check for the uncredited use of ideas). The instructor allows us to see our "originality reports" (indicating how much of the text was a direct copy of the words of someone else in their database). I submitted my paper and I got back 18%. I was floored. I clearly didn't quote that much. And I was pretty certain I didn't copy and paste from articles (or--and this is kind of what my previous post that I'll get around to soon was about--websites or wikipedia[!!]).
Turns out that I submitted the paper with my references section left on. I clicked the little "exclude bibliography" tab, and my originality report went down to 5%. Then I looked at what was coming up as unoriginal.
I don't know how many matching words are necessary in a phrase for it to be tagged as copied, but, as I was writing on affirmative action policies, phrases such as "gender-based preferential selection policies" are quite common, both in my paper and in the literature on the topic. So those came up a lot. Also things like: "women were selected on the basis of either sex or merit" were found. These are common phrases and bound to come up a lot.
Anyway, more to come on this (well, not this in particular, but a similar) topic soon.