Its both. There is a lot of research done on CEO pay actually.
A lot of it is pretty terrible because it doesn't take into account what the companies actually do, the size of the companies etc....
but there is still some basic rules you can draw from it.
http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2159119
Is a pretty detailed analaysis you can DL for free.








