Adam Liptak explains that by the numbers of overrulings, the Roberts Court is actually less activist. This is a point Jonathan Adler has been making for a while. (Check out also the NYT interactive graphic.)
But I’m not sure that aggregate numbers capture it all. Consider, for example, three First Amendment overrulings of the Roberts Court: Citizens United, U.S. v. Alvarez (the stolen valor case), and U.S. v. Stevens (the “crush video” case).
I would say that Citizens United has had a great impact on U.S. society (for good or for bad), while Alvarez and Stevens have had virtually no impact.
So my question is whether there have been more significant overrulings by the Roberts Court than prior courts. I don’t know the answer, and to answer it I’d have to start by having a good, consistent definition of “significant.” I’ll have to think about this for a while, and I don’t at all know how the Roberts Court would fare under this measure, but I do think that this point is not captured in Adam’s article or Jonathan’s posts.