What rules are used for grade progression in other countries? I mean specifically, for ballroom competitive dancing, progressing from, say novice to intermediate and so on. How many wins are allowed and so forth? I've tried looking on various web sites, but this information doesn't seem to be public

For the US you can look at http://usabda.org/dancesport_competitors/rules-policies-bylaws/dancesport_rulebook/index.cfm Look for 4.5.2.1 for details of how proficiency points are awarded.

Note that in USABDA competitions there is no *minimum* number of proficiency points required to advance to the next level. You can start wherever you want, and you can move up whenever you feel like it. The points are there to force people who have achieved a certain amount of success at a lower level into the higher levels. So, if you have three proficiency points in a level you can't do that level any more and have to move up, but you don't have to wait until you have three points to move up.