How much longer does Lane Rotation take?

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DerbyNut
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How much longer does Lane Rotation take?

Post by DerbyNut »

Our pack uses DerbyMaster software and have always does Double Elimination method. Our new PWD person says it would be more fair to use Lane Rotation. So how much longer would this take? We have about 50 boys with a 3 lane track. Would you suggest Lane Rotation over Double Elimination?

Thanks!
dna1990
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Re: How much longer does Lane Rotation take?

Post by dna1990 »

A PerfectN setup will race each car in each lane. So if you have 50 racers and can manage one race per minute, then it will take 50 minutes.

Most PerefctN charts will do a good job at placing a racer evenly distributed throughout the race, so nobody gets bored 'waiting' any longer than anyone else.

Hope that helps. GPRM's software site has details on why DE is not a supported style.
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Stan Pope
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Re: How much longer does Lane Rotation take?

Post by Stan Pope »

The time to run a DE chart depends on how many cars compete, how many cars compete in each heat, and how each "heat" is defined (some folks run make a single run for each heat and some do "best 2 out of 3 with some lane swapping.) I would rather extend the DE to a quad elim than run "best 2 out of 3" for each heat. Generally, if cars are close enough that they split the first 2 runs, the deciding run tends to provide no more accuracy than just deciding based on a single run. If "bye run" heats are avoided, the number of heats can be estimated from a script referenced in http://www.stanpope.net/nelim.html.

The time to run a Rotation method (there are several) generally depend on how many cars compete and how many times you have each car race. For lane equity, the number of times each car races is usually set to some integral multiple of the number of lanes, and seldom fewer than 4 to 6 times. PPN charts running each car twice per lane (a common plan) will take approximately twice as many heats as there are cars.

As folks usually do it, the time to run a DE on a 2 lane track is about the same as the time to run each car 6 times on a rotation method. Rotation with good opponent equity, even by points scoring, tends to give better acuracy for 2nd through 4th place than DE.

There are other considerations. What is it worth for the vast majority of entrants to go home with at least one heat win?
A 4 lane 8 heat rotation method tends to send more than half of the entrants home without a heat win. 2-lane DE sends about 25% home without a heat win. Run on 3 lanes the number grows to about 45%. Increase the elimination count (and number of heats) and 2-lane 4E reduces the winless count to about 6% and 3 lane 4E reduces the winless count to 20%. Both enhance the accuracy of trophy awards for 2nd through 4th to a level comparable to a good rotation chart.

Our district races traditionally awarded 5 trophies and several years ago we changed over from a DE 2 at a time to a 5E 3 at a time format which had good 5 trophy accuracy and about 12% winless. The average number of heats per entrant is around 8, whereas before it was around 4, I think. (They ran a truck load of byes though so the first half hour was pretty dull until the bye's were eliminated.) We have no byes now until a all but one of the competitors for a place in the finals has been eliminated. When all 5 finals places are determined, we run a ladder in which the 5th finalist races the 4th finalist with the lower seeded (5th finalist) needing to win twice before the higher seeded wins once in order to continue racing against higher seeded racers. So there are from 5 to 10 one-on-one heats with random lane assignment (draw for lanes) to complete our finals. On good tracks, we have only occasional place changes from the finals.

Hmmm... more than you wanted to know, I expect, but once you get me started ... In the words of Tom Lehrer from "The Irish Ballad", "My tragic tale I won't prolong, Sing rickity-tickity-tin, My tragic tale I won't prolong, And if you did not enjoy my song, You've yourselves to blame if it's too long; You should never have let me begin."
Stan
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DerbyNut
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Re: How much longer does Lane Rotation take?

Post by DerbyNut »

Our pack does the races by dens. And then the top three winners from each den race in the overall pack race. We always ran it as a DE race because our track is a new 3-lane aluminum track and none of the lanes were any better/worse than the others. But we always had trouble determining who came in 3rd place until we looked at the times and picked the fastest. The one thing I did like about doingit as DE is atleast when it came down to the final two boys, they knew whoever won was a winner. Doing it as lane rotation and taking the average of the times, there is no final race for the winners. Everyone waits for the final times to be averaged and posted by the computer.
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Re: How much longer does Lane Rotation take?

Post by gpraceman »

I'd recommend Perfect-N over Lane Rotation. They both make sure that each racer runs down each lane (something DE cannot guarantee). All racers will get the same number of runs (certainly not true for DE). However, with Lane Rotation, racers pretty much race the same opponents over and over. That is pretty boring. It also isn't good for Billy that gets beat by Johnny heat after heat. Perfect-N type charts give each racer a variety of opponents.

In terms of the amount of time needed, you can run a LR or Perfect-N race faster than a DE race. With DE, you only know who is racing in the current step of the ladder. With Perfect-N and LR, you know the entire schedule for the round. As such, you can get cars pre-stage and make sure that there are cars ready to load as soon as the current set is running down the track.

For those that feel that LR and Perfect-N are anti-climatic, you can always advance the top racers to run for the trophies. This is advisable with larger race groups anyway.
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Re: How much longer does Lane Rotation take?

Post by DerbyNut »

Our dens have different number of boys in each. One den has 17 boys and another has 7, etc. So taking the winners and running a final for each den won't really work. I'll have to think on this and see what is best.

Thanks!
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Re: How much longer does Lane Rotation take?

Post by gpraceman »

DerbyNut wrote:Our dens have different number of boys in each. One den has 17 boys and another has 7, etc. So taking the winners and running a final for each den won't really work. I'll have to think on this and see what is best.
For the smaller den, there is no need to run a finals.
Randy Lisano
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Re: How much longer does Lane Rotation take?

Post by DerbyNut »

I was doing my math and for a 3-lane track with 10 boys in a den, it is 30 races right? You just multiply the lanes by the number of boys right?
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Re: How much longer does Lane Rotation take?

Post by Stan Pope »

DerbyNut wrote:I was doing my math and for a 3-lane track with 10 boys in a den, it is 30 races right? You just multiply the lanes by the number of boys right?
No, If you have 10 boys to race and a 3 lane track, it takes 10 heats to give each boy 3 runs.
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Re: How much longer does Lane Rotation take?

Post by gpraceman »

DerbyNut wrote:I was doing my math and for a 3-lane track with 10 boys in a den, it is 30 races right? You just multiply the lanes by the number of boys right?
No, that is not correct. Remember, the other lanes are being filled with cars too.

See my response at viewtopic.php?f=16&t=5246
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Re: How much longer does Lane Rotation take?

Post by dna1990 »

Excellent point by Randy above, in that PerfectN allows for the full schedule to be set and printed as soon as the field of cars is closed.

This will lead to much faster staging and the organization portion of the race. Versus having to hunt down returning cars all the time.

And yep, regardless of lanes - the numbers of heats will equal the numbers of racers.
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