The 'play against computer' levels don't have floating rating anymore so how should

I don't see any nominal ratings.

@mcgoves when you start a game against computer level 3, it says 1400. That's what I'm calling the nominal rating. Maybe it doesn't show this number before you have started the game.

I would ignore the nominal rating, and just pick a level that's a little better than me, and another that's a little weaker. Or, consider it to be a rating system that goes from zero to (about) 8. Try and estimate your own rating.

OK cool mcgoves but if the answer to "what does this thing mean" is "just ignore it" then maybe they should delete it from the interface?

I just don't know what it means, so I can't help you there. I vaguely remember reading something about it once, but can't find the thread, and it's probably been reconfigured in the interim, so I bite my tongue.

Probably best to remove these ratings. Included a brief explanation in github.com/lichess-org/lila/commit/d4a823c270f54fec9958a679897d631ffea0af0c.

Thanks revoof for your explanations! I think those numbers would still have some value to compare the different ai difficulty settings to each other, like you can infer from them that if you win vs level n 50% of the time then you should probably win vs level n+1 15% of the time. Also if I understand right level 8 isn't unrestrained stockfish it's still limited. I assume that in the future lichess will change its 'play against the computer' implementation so you face ai opponents that are more human-like, but this is in lichess right now only with the experimental bot opponents.

I would like also a definitive conclusion about level 8 being full strength. my current understanding (belief, somewhat informed, and perhaps from rough reading to revoof links (or contained links)) is that it is still going to make mistakes under some probability (whether itself directly controlled, or relying on tree exploration known quirks as function of search parameters).

I kind of remember seeing a comment or issue about implementing a full engineXengine max ELO mode (sorry foggy).