SEEDING SYSTEM EXPLAINED
Why do we have a seeding system?
The reason for the seeding system is to eliminate, as far as is possible, the chances of a faster driver being held up by a slower driver on a competitive stage. How does it do this?
It does this by ascertaining the speeds of all drivers, relative to all other drivers, and ranking them in order of speed, not results. This is done on the basis of stage times set in ARC events, over a driver’s last three rounds.
Simple in principle, but how is the co-efficient calculated?
The mathematical process by which the seeding co-efficient, also known as the “Driver Performance Index” (DPI), is calculated is a complex one.
- It starts with establishing a “Stage Performance Index” (SPI) for all competitors for all competitive stages in ARC events. The SPI is calculated by dividing the fastest competitive stage time by the stage time of the driver for whom you are calculating the SPI. This will result in a value of less than 1, except that the SPI for the driver who recorded the fastest stage time will be 1. A driver who takes twice as long to complete a stage as did the driver who recorded the fastest stage time will have a SPI of .5000.
- From the SPIs an “Event Performance Index” (EPI) is calculated. The EPI for a particular competitor is the average of the “best two thirds” of his/her SPIs. By effectively discounting the worst third of a drivers SPIs, the likelihood of an unrepresentative time, where a driver might for example have been caught behind a slower vehicle or had a puncture, are all but eliminated. This gives a truer indication of a driver’s typical speed.
- An EPI will only be calculated from an event when a competitor has completed a minimum of six competitive stages. Again, this ensures as far as is possible that only representative data is used as a basis for determining seeding positions.
- From the EPIs is calculated the Driver Performance Index which is the average of the best two of the last three EPIs.
The seeding system is not skewed by poor performances which are not typical of the driver, as the worst 30% of his/her performances are discarded.
Event Performance Indices are only valid for two years. This ensures that drivers are seeded on the basis of their current form against current competitors, and not on the basis of their performance five or more years ago against drivers no longer competing.
By using only a competitor’s last three events, the system is capable of reacting quickly to cases where, for example, a competitor upgrades his/her car and suddenly becomes much quicker.
It is not necessary for a driver to be a finisher in order to get an Event Performance Index. So long as he completed six competitive stages throughout the event, an EPI will be calculated. Seeding is based on ability to drive fast, not on ability to nurse slow machinery through to the finish.