When I retire from a game there's information on relative ranking of various empire-wide statistics as compared to the other empires in the game. Is that information available in-game? Have I missed something?

I've been trying to find some kind of "galactic leaderboard" in the toolbars and I don't think there is one. It would be a great addition to the game even if it requires some sort of research to unlock.

Not for now. But an in game stats screen is on our wishlist.

You can get the scores by hovering over the upper-left-most icon, the spiral arms thing. All that is needed is to put more detail onto that screen, same as what you get when the game is over. Personally, I would love to have some more information about how the "score" is computed. On most games at normal difficulty, I seem to be dead last in score by turn 100. If I knew where the AI's were outperforming me, I could get better.