Why I Use CC-BY-SA Licenses
I don’t mean why do open scholarship in general, but why my specific choice of Attribution-ShareAlike?
I avoid NoDerivs (ND) because I want people to build on my work, make corrections, add new analyses.
I use ShareAlike (SA), though, because I want to be able to incorporate corrections and new analyses back and want to avoid private forks of projects. Note that when it comes to software, I generally favour MIT/BSD-style licenses that aren’t viral. But when it comes to data and analyses, I want the openness to the viral.
Perhaps more controversially, I avoid NonCommercial (NC). My reason is simple: I don’t want someone who wants to use my work in a commercial package to have to waste time reinventing the wheel and redoing everything just so they can use it. Duplication of effort doesn’t help anyone. Because of the ShareAlike, a commerical project can’t make private forks. I don’t care if someone is making money as long as improvements they make to my work are shared back.
Creative Commons doesn’t have a license that requires ShareAlike but not Attribution but, even if they did, I’d use Attribution (BY). Particularly in scholarship, I think it’s important to give credit where credit is due. Plus having a chain of who did the work is useful for providing corrections upstream.
My arguments for using ShareAlike and Attribution are why I don’t like just putting things in the “public domain” / under a CC0 license. (Incidentally, I put “public domain” in quotes because it’s an ill-defined concept, which is why the CC0 license was developed in the first place. Even if you’re not persuaded by my arguments for BY-SA, at least use CC0 rather than saying “public domain”).
Finally, I’d be remiss if I didn’t acknowledge the great work of the Creative Commons organization in making all this possible.