How we calculate your seeding
There are 5 steps involved in the seeding process:
1. Choosing the weightings of the different rides
2. Establishing a base event
3. For each ride, adjusting the winner’s time and calculating its difficulty relative to the base event
4. Calculating an index for each rider
5. Calculating a weighted average for each cyclist
6. If your weighted average index is better than the lower limit of your current seeded group, then you are eligible to move to a better group.
In more detail:
1. Choosing the weighting of the different rides
You need more than one result to make up your total seeding. Generally all rides that count will count 1/3 of your total seeding. In other words, the average of your best 3 results will be used. The exceptions to this are events which have intermediate checkpoints along the way. Currently those are the Cape Argus Pick n Pay Cycle Tour, Die Burger Cycle Tour and the Ninety Niner which will each count 50% (half your total seeding, provided they were one of your best two results).
In order for a route to count at all it needs to meet the following criteria:
• 80km and over – no climbing requirement, no other penalty; or
• 750m of climbing, regardless of distance, no other penalty; or
• 60km with 15% penalty (added to your seeding index)– no climbing requirement; or
• 400m climbing with 15% penalty, no distance requirement
• 50km and over – no climbing requirement, no other penalty; or
• 750m of climbing, no other penalty; or
• 35km with 15% penalty – no climbing requirement; or
• 400m with 15% penalty, no distance requirement
In addition the following must apply:
• Must be RaceTec timed
• There must be no problems that prevent the calculation of the event’s difficulty relative to the base event. On the event management side, this could happen if too many riders follow incorrect routes. It also often happens for shorter routes of events where the majority of participants are riding “just for fun” and their index for the event in question prevents an accurate calculation of the event’s difficulty.
Only your best results are used for seeding purposes – the rest are discarded from the calculation. (So it never hurts to have a bad result because a bad result is better than no result at all!). You need enough results to make up 100% before the seeding system starts working properly for you.
If you do not have enough results to make up a full seeding a penalty of 20% is added in the case of 2 results missing, or 10% in the case of one result missing.
2. Establishing a base event
Step 3 below relies on us being able to compare the difficulty of different events. And for that we need a base event. Ideally we would just use the latest Cycle Tour (Cape Argus Pick n Pay Cycle Tour 2012) but to enable us to do the calculation equally well for all events across the country, we first perform steps 3 and 4 below for the 2012 Momentum 94.7 Cycle Challenge and then use the better of the two indices as our theoretical base event. The result is that both these events are treated as being slightly easier than the theoretical base that we use in practice.
3. For each ride, adjust the winner’s time and calculate the difficulty (beta)
Some races have a better quality of field than others. For instance, some events may have visiting pro riders participate and some events (especially shorter routes) have no top riders present. So we adjust the winner’s time to take this into account.
It would also be unfair to get the same seeding for being the same percentage behind the winner in a fast, flat ride as in a hilly, difficult ride. To allow for this we calculate a difficulty or “beta” factor. This makes the gap between the winner and you count less in difficult conditions and more in easy conditions.
First, an extract is done of all the riders who did the event in question, as well as the base event. Every rider with an index better than 100 is taken for this calculation. The assumption is made that the same riders should have the same index for both events, so the winner’s time of the funride is now adjusted and the “beta” is calculated to achieve this.
In statistical terms, a linear regression is performed for the event relative to the indexes of the people in the event who also rode one of the base events. This determines how much the winner’s time should be adjusted and what the difficulty factor “beta” should be. There is no subjectivity in this process – it is an automated calculation without human intervention.
In layman’s terms, the adjusted winner’s time should be roughly the time that the winner of an event would have done if the winner of the Cycle Tour had ridden that event at the same effort. The beta factor will be 1 if the event is as difficult as (i.e. on par with) the Cycle Tour, less than 1 if it is easier (eg flat and fast), and more than 1 if it is harder (eg hilly or very windy).
4. Calculating an index for each rider for each of the different seeding rides
This calculation is done for every result in an event that counts for seeding.
The formula is: (your time / adjusted winner’s time – 1) / beta value and then expressed as a percentage.
To the answer you get for each result, you need to add the following:
If the seeding is to be used for MTB specifically, 15% is added IF the event being used is a road ride.
If the event took place more than 3 months ago, 1% is added for each further month that has elapsed (up to 5 years after which it will no longer be used)
If the event is a short route or has minimal climbing, a further 15% may be added.
Note that the Beta value does not display on the current seeding lookup screen – this will be fixed by the beginning of 2013.
So if the adjusted winner’s time is 3:20 and your time is 4:00, and the event took place 9 months ago and is the same difficulty as the Cycle Tour (base event) then your index for the event is (240/200 – 1) = 0.2 = 20%. Plus 6% for the time elapsed gives 26%.
5. Calculating a weighted average of the different rides for each cyclist
Your indices for all the events you have ridden are sorted from best to worst. All results below 4th place in your list (assuming the weightings of your best 3 add up to at least 100) are then discarded, and your overall index is just an average of the indexes from your top 3 rides.
A worked example:
Let’s say you have ridden 4 events where the abovementioned criteria are met and the results are all recent (less than 3 months old) so no penalties have been added
(a) Event A (counts 34%) – time 3:26
(b) Event B (counts 34%) – time 3:13
(c) Event C (counts 34%) – time 2:57
(d) Event D (counts 34%) – time 3:15
The respective adjusted winner’s times are 2:32, 2:34, 2:14 and 2:30 with difficulty factors 0.8, 0,95, 1 and 1.3 respectively.
So your index for the rides would be:
(a) (206/152-1)/0.8×100 = 44.41 (counts 34%)
(b) (193/154-1)/0.95×100 = 26.66 (counts 34%)
(c) (177/134-1)/1×100 = 32.09 (counts 34%)
(d) (195/150-1)/1.3×100) = 23.08 (counts 34%)
You would then sort these in order of index (best to worst) which would be (d), (b), (c), (a).
So race (d) will count 34%, race (b) will count 34%. At this point we only need another 32% to get to 100% so race (c) will count 32%, and race (a) will not be used at all.
Your overall index is therefore 0.34 x 23.08 + 0.34 x 26.66 +0.32 x 32.09 = 27.82%.
6. Get your new number…
If your seeding has improved, please contact the PPA Office to arrange upgrading your seeded number. An admin fee of R50 is payable, and you need to return your old (current) number before you can be issued with a new number.
In the seeding lookup screen, you’ll see your results have been sorted to show your best rides first, in other words the rides that count towards determining your seeding. All other results are then show in date order, with the most recent event at the top of the list.