Accuracy of PPN in finalist selection

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korey99
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Accuracy of PPN in finalist selection

Post by korey99 » Fri Jan 16, 2015 2:30 pm

Hello all-
Following some feedback from my committee, I've determined that using a 2-round points-based system for my pack level race is going to be necessary, but time is limited. If I have ~16 cars and run a PPN schedule, 3 lanes, only 1 round, scored by points, followed by a 7-car 2-round CPN finals, will I be reasonably certain that I'll have the top 4 in that 7-car field? I did read that "PPN is excellent at ranking the N best cars among the highest scoring 2*N places" but I'm not sure whether 1 round is sufficient. Also, is the risk of ties very high in this scenario?
Thanks,
Korey



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gpraceman
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Re: Accuracy of PPN in finalist selection

Post by gpraceman » Fri Jan 16, 2015 3:45 pm

I'll let Stan chime in on that question, since he created that scheduling method.

In terms of time management, here's some things that will help you:
  • Each car should have its own assigned "parking spot", so it is easy for your crew to pre-stage the cars for each heat.
  • Assign at least two people to your staging table, to pull cars for the next heat.
  • Assign at least one person to put the cars back in their assigned "parking spot" after their heat is completed.
  • Once you have your schedule(s) created, print out a copy and give it to your crew at the staging table. This will help them ensure that once one set of cars is racing down the track, then they have the next set of cars lined up and ready to load to the track. They may even be able to get multiple heats pre-staged. Note, it is faster for the crew to go by the printout than trying to depend on looking at software's racing screen via your projection system.
  • Make sure that your MC is not slowing down the pace by inserting too much commentary.
  • Practice with the software before the race, so you are comfortable with the steps needed to run the race in the fashion that you need.


Randy Lisano
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Awana Grand Prix and Pinewood Derby racing - Where a child, an adult and a small block of wood combine for a lot of fun and memories.

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Stan Pope
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Re: Accuracy of PPN in finalist selection

Post by Stan Pope » Fri Jan 16, 2015 6:10 pm

korey99 wrote:Hello all-
Following some feedback from my committee, I've determined that using a 2-round points-based system for my pack level race is going to be necessary, but time is limited. If I have ~16 cars and run a PPN schedule, 3 lanes, only 1 round, scored by points, followed by a 7-car 2-round CPN finals, will I be reasonably certain that I'll have the top 4 in that 7-car field? I did read that "PPN is excellent at ranking the N best cars among the highest scoring 2*N places" but I'm not sure whether 1 round is sufficient. Also, is the risk of ties very high in this scenario?
Thanks,
Korey
In the simulations that led to the 2*N recommendation, I sought probabilities > .95, i.e. 19 times out of 20 the top 2*N finishers would include the objectively fastest N racecars. 7 for 4 trophies is a bit shy, but the probability is still good. The deserving racer is unlikely to be left off the platform.

The deeper you go into the group of racers, the more likely there will be ties to resolve. I would expect a 2 or 3 way tie for 7th place in one round on 3 lanes ... there are 7 possible scores (3 through 9) to be shared among the 16 racers!

I understand that the tradition in your area is for the boys to stage their own cars. (Specifically, only the boys touch the cars, and only their own cars, from start to finish!) This, of course, affects the time and would cause some adjustments to Randy's suggestions. It is helpful for a "shepherd" or two to make sure that the racers to be in the next heat or two are aware and moving to get their cars from the pit. And the starter should call up the racers in order starting with the lane nearest the starter! So there are two places that a printed heat schedule would be helpful!


Stan
"If it's not for the boys, it's for the birds!"

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