The concepts behind Kudos Rating aren't complicated, but they are a little different to how you may have seen players rated and ranked before.
Many sports have rating systems for professionals where points are awarded based on prize-money or perceived tournament importance. For Kudos Rating there is no subjective element - rating points are won or lost purely based on match results and quality of opposition. We let amateur players guage their playing strength, and chart their progress, and we hope this will help increase commitment the sport.
Kudos Rating is perfect for calculating relative skill levels of players in 1 vs 1 games or sports. It uses as a starting point the Elo Rating System which was devised for rating Chess players (and it still used for this today).
It can though be used for ranking pretty much anything where players or teams play each other - there are Elo rankings calculated for international football teams for example.
It doesn't make so much sense to use Kudos Ratings when there is an absolute measure of skill though, for example in athletics when it's easier to compare best times, or in golf where the handicap system is already in place.
The Central London Table Tennis League started using Kudos Rating during the 2014/2015 season. This league has over 300 players spread across 5 divisions, and plays around 5000 matches a season.
As well as providing allowing players in the league to track their progress, the Kudos Ratings have also been used to generate handicaps for cup competitions.
Competition organisers can define the policy for setting initial ratings. Everyone can start with the same initial rating, or initial ratings can be estimated. After a while the initial rating won't make much difference, but setting it sensibly will help calculate accurate Kudos Ratings more quickly.
When a league has multiple divisions, it would be sensible to allocate intial ratings based on the division a player is in.
Kudos Ratings have a statistical basis. The number of points allocated for a win or loss is determined by how likely that result was. It is unlikely that a weak player will beat a strong player, so if he does he is given a lot of points.
The statistical likelihood of such a victory is also determined by the number of games a match is played over. It is much easier for a weak player to beat a strong one in a best-of 1 match than in a best-of 7.
Kudos Ratings are designed so that a 200 point rating difference means a weaker player has around a 25% chance of beating a 200 point stronger player, over the number of games specified in the league Best-of field. This is nice because it gives players some idea of how likely they will be to beat a new opponent.
If a match played over a different number of games to the league default, then Kudos Rating does the statistical calculations to award the appropriate points, based on the new probability of victory. (For the example of the 200 point weaker player, if he has a 25% chance of winning in a 1 game match, this is statistically reduced to just 7% for a best of 7 match, and he will be given more points accordingly.
If the league default Best-Of value is changed, then the points awarded for previous matches will not match those for future ones. In these cases, the league organiser can either recalculate all ratings from scratch to resolve this issue immediately, or ignore the issue and allow ratings to gradually correct themselves over time as new matches are played.