The greater the difference in grading, the more likely it is that the higher-graded player will beat the lower-graded player, all else being equal.
Yeah, but is it ever? Equal, I mean. Custardchuk may be a better player than Ruxpin, but what if Australia is playing footie at the time? Urbanus may be a more renowned athlete than Coach Ha, but what if they are playing on the Coach's home turf at the SW ProAms, and Urbanus has to use a two-prime? I may be able to whup four Hustlers in a row, but what if I'm still feeling the ill effects of shutting down the bars with custardchuk from the night before?
Still, I agree with custardchuk that this is a step in the right direction as concerns a cohesive ranking system. At the present time, there is no official ranking system outside of certain promotions, usually limited in scope to a single city (such as the Philly City League or your MetaWealth Championship.) The current system used by WorldRPS is definitely suspect. After every International World Championship (IWC,) the new ranks are mentioned: "Bob Cooper is the top-ranked player in the world" "The Saint is the top-ranked American player and the second-ranked player in the world." Nothing against either of these fine gentlemen, but since when does winning a single tournament make one the top ranked player in the world? Since when does coming in second in a single tournament make one the top ranked player for one's country? Who's the third ranked player? Is there a top ten list? Of what use is a ranking system with room for only two players? Ranking systems are generally used to set up tournaments, not the other way around. This bothered me when I was declared the top ranked player in the US (for making a final 8 appearance at the 2003 IWC) and it bothers me still. Such ranking systems are useful for the players' egos and for the promoter's marketing purposes, but it does little else.
There are a few problems with setting up a RPS ranking system. First, you don't want to reward players who compete once, win, and retire with a 100% batting average. Second, you don't want a system where one can gain the top rank just by playing more often than anyone else. However, both factors need to be taken into consideration.
The American Pool Association uses a ranking system of 1-5 for League Play. Rank is calculated based on wins and losses, and the skill level of your opponent is taken into consideration. If the players have an equal rank, then the match is a "first to two" affair. If the players ranks are unequal, the higher ranked player has to win more games to win the match.
The Sumo ranking system is also interesting. Rikishi are ranked according to tournament wins and losses, but the highest ranks must have a losing record in two consecutive tournaments before demotion. It's hard to get to the top, but once you're there, it's harder to move you.
There really isn't much need for a RPS ranking system, other than curiosity and bragging rights. In truth, when you're actually in a tournament environment, there are only two ranks: "me" and "everybody else."