PPA Seeding Beta's

[Patchelicious]

I think this topic has been debated lots in other threads and needs a NEW thread of its own.

 

Its not a rant, as we all suffer/benefit from the same beta values.

 

This thread is to ask the question on how is it calculated.

 

Here is why I am asking.....

 

Sun 20/09/2015 Pennypinchers Karoo to Coast 100km MTB challenge (100km)

Winning Time3:12:18

Beta 1.01

 

Sat 31/01/2015 Action Ford Berge en Dale Classic 2015 (102km)   

Winning Time 2:25:16

Beta1.00    

 

Sun 25/01/2015 The Value Logistics Fast One 2015 (96km)  

Winning Time 2:09:22

Beta 1.00

 

Here are 3 very different races ALL with the same Beta value.

 

How can you say the Karoo2Coast is the same as the FastOne or that the FastOne is the same as the Berge n Dale?

 

Sometimes they adjust the winner time to "adjust" it, but if the correct beta was applied that would not be needed. In the 3 examples above those are the real winning times.

 

So my questions are:

1. Who decides on these betas.

2. What are the criteria that they use.

 

Simple and not ranty

Edited October 20, 2015 by Patchelicious

[HBO]

It does seems strange. From what I heard- not a reliable source, so don't know how correct it is- is that all races are compared to the Argus. In other words if the Beta is 1, then the difficulty is the same as the Argus.

 

If its less than one, then it is easier than the Argus and visa-versa.

 

As I said, this is not from an expert so I don't know whether this is correct or not but irrespective of this, it doesn't make sense that Fast one and Berge en Dale can be of the same difficulty.

 

I also don't know if one can compare MTB races with road races and if there beta are calculated on the same basis.

 

It will be interesting to see what the experts say.

[KaKa]

im not knowledgeble enough to answer the question.

however, i remember it was said that the argus lite times would not be used for seeding.

 

 

"they" are using it to seed the races (just check my index)

[Patchelicious]

It does seems strange. From what I heard- not a reliable source, so don't know how correct it is- is that all races are compared to the Argus. In other words if the Beta is 1, then the difficulty is the same as the Argus.

 

If its less than one, then it is easier than the Argus and visa-versa.

 

As I said, this is not from an expert so I don't know whether this is correct or not but irrespective of this, it doesn't make sense that Fast one and Berge en Dale can be of the same difficulty.

 

I also don't know if one can compare MTB races with road races and if there beta are calculated on the same basis.

 

It will be interesting to see what the experts say.

You are correct in theory:

 

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).

Edited October 20, 2015 by Patchelicious

[PJP2013]

The beta favours the Cape Town races for Argus seeding.  

 

This year amashova was 1.03 last year it was 1.11. Ask anyone who rode and they will say weather conditions were worse this year than last year, this year being a harder ride.

 

But because times were faster the beta is lower to compensate for that, even though it may be because riders were stronger this year?

 

Just my opinion. PPA looking after their members

[Sparki 1]

I think this topic has been debated lots in other threads and needs a NEW thread of its own.

 

Its not a rant, as we all suffer/benefit from the same beta values.

 

This thread is to ask the question on how is it calculated.

 

Here is why I am asking.....

 

Sun 20/09/2015 Pennypinchers Karoo to Coast 100km MTB challenge (100km)

Winning Time3:12:18

Beta 1.01

 

Sat 31/01/2015 Action Ford Berge en Dale Classic 2015 (102km)   

Winning Time 2:25:16

Beta1.00    

 

Sun 25/01/2015 The Value Logistics Fast One 2015 (96km)  

Winning Time 2:09:22

Beta 1.00

 

Here are 3 very different races ALL with the same Beta value.

 

How can you say the Karoo2Coast is the same as the FastOne or that the FastOne is the same as the Berge n Dale?

 

Sometimes they adjust the winner time to "adjust" it, but if the correct beta was applied that would not be needed. In the 3 examples above those are the real winning times.

 

So my questions are:

1. Who decides on these betas.

2. What are the criteria that they use.

 

Simple and not ranty

Phone PPA and ask them

[Skubarra]

The beta favours the Cape Town races for Argus seeding.  

 

This year amashova was 1.03 last year it was 1.11. Ask anyone who rode and they will say weather conditions were worse this year than last year, this year being a harder ride.

 

But because times were faster the beta is lower to compensate for that, even though it may be because riders were stronger this year?

 

Just my opinion. PPA looking after their members

 

What was the adjusted winning times for both races. You cannot just look at the beta alone

 

I remember a similar thread on the 94.7 for 2014 & 2013 where the change in betas were weird, but you also had to look at the adjusted winning time then it made more sense.

 

PPA looking after their members? I would have loved that to be true 

[Patchelicious]

What was the adjusted winning times for both races. You cannot just look at the beta alone

 

I remember a similar thread on the 94.7 for 2014 & 2013 where the change in betas were weird, but you also had to look at the adjusted winning time then it made more sense.

 

PPA looking after their members? I would have loved that to be true 

In the examples I gave above non of the times were adjusted.

[Bankie99]

Yeah I was having this chat with some of the guys in my team last night and asking which race they thought is harder, K2C or 1 Tonner.

 

The guys who did both all agreed k2c is harder but yet the beta for k2c 2015 is only 1.01 and 1 Tonner is 1.29

 

Knysna cycle tour road 2015 beta is 1.17 now if you ask me I would rather do knysna cycle tour twice before doing k2c once

Edited October 20, 2015 by Bankie99

[usxorf]

Just speculation, but these being outside of cape town races, there are less samples for them to do a "statistical regression", and / or the samples they do have are skewed towards the elite side (for whom the difficulty of a race has a smaller impact on time).

 

So the beta leans more towards 1 outside of the cape, regardless of difficulty.

[Skubarra]

In the examples I gave above non of the times were adjusted.

 

I know you started this topic to try and understand and not to get a little lecture, but I have long given up in trying to understand how they come up with their betas/adjusted winner times.

 

PPA is not exactly transparent in how they calculate it - I can only imagine there is some thumb sucking involved.

 

All I know is that when I race a lot and do well my seeding improve, and when I don't my seeding starts to drop after 6 months. I think having a "seeding strategy" where you only do 1 or 2 seeding races a year is bound to leave you disappointed.

Edited October 20, 2015 by Skubarra

[pe3nguin]

1.03 

That's all I have to say on the matter >.>

[Patchelicious]

I know you started this topic to try and understand and not to get a little lecture, but I have long given up in trying to understand how they come up with their betas/adjusted winner times.

 

PPA is not exactly transparent in how they calculate it - I can only imagine there is some thumb sucking involved.

 

All I know is that when I race a lot and do well my seeding improve, and when I don't my seeding starts to drop after 6 months. I think having a "seeding strategy" where you only do 1 or 2 seeding races a year is bound to leave you disappointed.

LOL thanks

 

The part I highlight here, is exactly why I started it.... I tend to agree with you. I think they are relucant to share because there is nothing to share.

 

I would love them to prove me wrong though and create and understanding as to how its done.

[DJR]

..................I have long given up in trying to understand how they come up with their betas/adjusted winner times...............

 

 And therein lies my path to seeding inner peace !   

[Winstonian1984]

Just come do either the red hill TT(3.5km) or Taal Monument TT(2.7km) and you will get a beta of 1.5 for a few minutes of suffering.     

[Patchelicious]

Just come do either the red hill TT(3.5km) or Taal Monument TT(2.7km) and you will get a beta of 1.5 for a few minutes of suffering.     

Are those both CPT based?