Measuring the dancer

About once a week someone on the dancefloor asks me "You're really good, why are you in beginners rather than through there in advanced?" There is a related set of comments I frequently get to the effect that I'm the best dancer in the class (which is rather embarrassing, since some of the other dancers are being paid to be there, and I'm not). In the time I've been dancing I've come up with a range of answers to these ranging from the offhand to the glib. The real reason is somewhat deeper.

As I understand it there are four ways to measure a dancer (we'll put aside the ballroom-like abstract definitions of perfection to be heckled another day):

1. How one dances with the best dancer on the floor: This is a common trap for dancers to fall into, since it looks and feels like one is dancing at one's best when dancing with the best dancer on the floor. Unfortunately it places value on "easy to dance with" attributes---partners who are not interested in their own style; who're four foot nothing with negligible inertia; and partners who are dressed for the style of dance you're dancing. The "best" partners are also in greater and greater demand as partners, encouraging unreasonable behaviour. This not only leads to the worst kind of partnerships (see the movie Strictly Ballroom) but offers little room for partners to develop.
2. How one dances with a particular partner: This is common for people who have a real-life partner who dances. It's great if dancing is something who do together to be together and everyone else is just cover for your dance floor antics. Unfortunately often it leads to couples who dance completely different with each other than they do with other people; in short, they're not dancing ceroc with each other, so the question of how well they're dancing it becomes moot.
3. How one dances with a dancer at one's own level: In theory this is a great measure, but in my experience it converges on case number one, because when dancing with good dancing one looks and feels at one's best.
4. How one dances with the worst dancer on the floor: The great thing about ceroc is that there are always beginners turning up, people who've never danced ceroc and often never danced at all. Dancing with hoi polloi requires excellent leading, the ability to recover from mistakes and competent move selection. These are the people for whom a single good dance can make the greatest difference to their evening (or the difference between coming back or not). These are the people who turn up in sneakers, two layers of satin or floor-length non-stretch dresses; these are the people who are demanding, not in their attitude, but in themselves; these are the people who will stretch your dancing. These are who I measure my dancing against.

So coming back to where we started: when will i move from beginners next door to advanced? when I'm confident I'm dancing at an advanced level with everyone in the beginners class. I don't mean dancing the lifts and throws, I mean the leading, the move selection, the extent of repertoire and the floorcraft.