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Simple Overview of Ratings ( PPI)OutlineMost bridge players like to see their scores and how they performed against the the rest of the participants. The Past Performance Indicator (PPI - was called "ratings") scheme calculates a figure based upon your recent results, which are expressed as a percentage, thus giving a way for members to monitor how they are doing on a day by day or month by month basis. You may look up your own percentage on your profile and even see your PPI history in graphical form. ( see detailed explanation and examples ) Our PPI scheme is considered to be one of the best in use in either the internet or indeed face to face bridge clubs. IntroductionGames involving partners of very different standards tend to be very uneven – an inexperienced player partnering a Grand Master may feel extra pressure, while a Grand Master may find it tedious to see partner make elementary plays. Similarly, two top players playing against two beginners may provide an uneven match. The key aspect about the PPI scheme is that it provides an approximate indication of the standard of the bridge players you are partnering and opposing. DefinitionThe PPI figures represent the percentage scores that a player would expect to average if partnering another player with the same PPI against a given field (ie the online club membership). PPI's should be used as a guide only and not taken too seriously. Other members looking at your profile (and vice versa) may see one of eight symbols:
How it worksThe formula calculates a PPI figure for each player, that expressed as a percentage, could be described as a handicap ( as in golf). This is then used as a handicap - or as the basis for 'seeding' in some of our Special Competitions. Your PPI figure is updated after every event in which you play in any rooms except the Social and Coaching Bridge Rooms, the Special Competitions Rooms and any room with IMP scoring. The update takes place as the event is archived. (A similar system could work for Butler competitions, though there are no plans for such at the present time.) The calculations take your partners’ and your opponents' PPIs into account as well as how many boards you play in each event. Remember, there is NO ADVANTAGE for higher standard players to play AGAINST less experienced players, as in doing so, their results must be much better than the norm in order to get a postive change in their PPI and the formula is designed to smooth out any discrepancies between ALL PLAYERS at the table. See our DETAILED EXAMPLES. The range of PPI figuresThere are no artificial limits to the PPI figures. The strongest players have PPI figures of 60% or more and intermediate players could have figures of less than 40%, a difference of 20%. The spread of PPI figures for players tends to form a Normal Distribution with the obvious mean of around 50% and with a Standard Deviation of around 5%. What this means is that about 68%, over two thirds, of all members will have a PPI between 45% and 55% and about one sixth will have a PPI above 55% and about one sixth will have a PPI below 45%. Two and a quarter percent of all members will have a PPI above a figure of around 60%. Bridge Club Live displays PPIs of members by way of one of four suit symbols on the profile of each member. This method was deemed the most popular in a referendum of members in 2005 and a further review in 2008.
Having selected these bands, it will therefore be found that :
PPI Reset PolicyThe PPI of a current or returning member will not be reset.
page last updated on September 21, 2011 |
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