Times vs Points

[gpraceman]

I'm not one to avoid some controversy, so I thought I'd pose the question of which scoring method people use and most importantly WHY?

Our first Awana Grand Prix, we used points scoring, since we didn't have a timing system, and ran into problems with some parents questioning the results. The next year we used a timing system and scored by times. Since then we have not had any problem with anyone questioning the results.

We have continued to use times scoring for two reasons. First, we have not seen a case where the timing system appeared to report an incorrect finish order. Secondly, looking at our past years race results, there are many cases of cars that had a very small standard deviation over the course of a race. To me that is an indication that the timing system does not have much variation in the accuracy of its times.

However, I have seen some concerns on this forum about using times scoring, so it would be good to hear what those concerns are and if there is any data to backup the concerns. I am more that willing to consider alternative ways of doing things, if there is significant justification for the change.

[Darin McGrew]

I'm not one to avoid some controversy, so I thought I'd pose the question of which scoring method people use and most importantly WHY?

We use points because we don't have a timer.

However, I have seen some concerns on this forum about using times scoring, so it would be good to hear what those concerns are and if there is any data to backup the concerns.

All things being equal, time is the most accurate measure of speed.

The question is whether all things are equal. There are many factors that could affect the comparison of times from the first heat and the last heat, starting with whether the track has been bumped during the derby.

For example, imagine that "something happens" that adds 0.1 second to everyone's time across the board. In a points system, there is no effect on anyone's standing. But in a time system, this is only true if everyone races the same number of times "before something happens" and "after something happens". If any car raced more times "before something happens" than another car, then it has a 0.1 second advantage in its total time.

[ExtremePWD]

In the absence of a consistent, positively actuated (to open) starting gate I would be concerned first with a slow opening gate triggering the start switch but delaying the start of the cars. This is somewhat addressed by a laser gate. There is also a an interaction between gate speed and the front geometry of the car. This is a variable that is out of the control of the racer but is controllable by the starter. Both of these concerns add a somewhat random (unless intentionally varied) influence to the car times and thus would not be evenly distributed across all racers. Even a points system can be influenced by this interaction. I am a proponent of the quick opening gates and would be more accepting of a timed competition if it were present. There still should be some form of control to guard for "bumped" tracks. Marking the track profile on the floor with tape could be one partial solution to resetting a "bumped" track.

[Darin McGrew]

I am a proponent of the quick opening gates and would be more accepting of a timed competition if it were present.

Absolutely. Starting gates that open quickly and cleanly are important for any derby. And they are clearly a prerequisite for any elapsed-time system, since there is no other way to measure the start time accurately enough for the results to be meaningful.

[Jungle Jim]

I always looked at it as being a "Pinewood Derby Race" not a "Pinewood Drag Race". As such times are not paramount. Racing against others is interesting, against the clock zzzzz.

And on a personal note: If racing against the clock is all we do (i.e. 3 trips or some derivative of this down the track for time only) then there wouldn't be the story to tell of how my sons' car was knocked out of his hands by the starter (accidentally, the guy - who is really a great guy - was turning around to see who was calling his name), while it was being videotaped, at the District race after having already won 7 heats handily; crashing to the ground and snapping off his wheel, duct taping it back on only to be beaten in the next rounds by Scouts he had already beaten who went on to take home hardware.

That's why it's called racing

[gpraceman]

I am a proponent of the quick opening gates and would be more accepting of a timed competition if it were present.

Absolutely. Starting gates that open quickly and cleanly are important for any derby. And they are clearly a prerequisite for any elapsed-time system, since there is no other way to measure the start time accurately enough for the results to be meaningful.

I agree with the both of you. If you use a timing system, you should make sure that you have a sart gate that will operate consistently. I'm not a fan of the spring loaded closed gates that must be manually opened. I'm glad that Piantedosi, providing a very popular track, has redesigned theirs so it will spring load open.

For example, imagine that "something happens" that adds 0.1 second to everyone's time across the board. In a points system, there is no effect on anyone's standing. But in a time system, this is only true if everyone races the same number of times "before something happens" and "after something happens". If any car raced more times "before something happens" than another car, then it has a 0.1 second advantage in its total time.

A 0.1 second example seems pretty extreme and I would think pretty noticeable. I've heard several concerns of the effects of bumping a track affecting the results. Has anyone really seen this to be the case? If a "bump" to the track can alter the outcome, it seems to me that the track itself is not very stable and should be reinforced. If the track gets a good whack, I could see that causing a problem. If the track is altered enough in its setup, then it will likely affect some lanes more than others, which would be a problem even running a points system.

[gpraceman]

I always looked at it as being a "Pinewood Derby Race" not a "Pinewood Drag Race". As such times are not paramount. Racing against others is interesting, against the clock zzzzz.

It may make it more interesting, but it may not be more fair. My concern with people using a points system is that they may not be considering that you really shouldn't use scheduling methods that do not provide a good number of opponents. Otherwise, a racer that may have been one of the fastest cars may place differently because they ran against a faster car, while others did not and won against lesser opponents. I shudder to think of someone using a lane rotation chart with the points system.

[Da Graphite Kid]

We've used a points system in the past since we had a finish line that could only tell us who was the first to cross (two-lane track). With a new track and a (hopefully) really accurate finish line timer this year, we will still use a points sytem. My personal concern being that this would help eliminate as many variables as possible. What racing method we will use has not been set in stone yet but I thinking of using a round-robin method... but what I learn from all of you Pineheads may change this!


Da Graphite Kid

[Jungle Jim]

I always looked at it as being a "Pinewood Derby Race" not a "Pinewood Drag Race". As such times are not paramount. Racing against others is interesting, against the clock zzzzz.

It may make it more interesting, but it may not be more fair. My concern with people using a points system is that they may not be considering that you really shouldn't use scheduling methods that do not provide a good number of opponents. Otherwise, a racer that may have been one of the fastest cars may place differently because they ran against a faster car, while others did not and won against lesser opponents. I shudder to think of someone using a lane rotation chart with the points system.

This is why it's called racing. There are always going to be variables. Any of you who follow racing (I do) know that the fastest car doesn't always win. You may run out of gas, blow a tire, have a pit mishap, but those things happen (in racing of course, not on a PW track).

How this translates to PW for me is that the track and cars will change during a race. Be this from humidity, temperature, vibration, someone bumping into it, etc. What we are opening ourselves up to is a veritable Pandora’s Box. How much technology must we induce into the program in the name of fairness?

[gpraceman]

This is why it's called racing. There are always going to be variables. Any of you who follow racing (I do) know that the fastest car doesn't always win. You may run out of gas, blow a tire, have a pit mishap, but those things happen (in racing of course, not on a PW track).

How this translates to PW for me is that the track and cars will change during a race. Be this from humidity, temperature, vibration, someone bumping into it, etc. What we are opening ourselves up to is a veritable Pandora’s Box. How much technology must we induce into the program in the name of fairness?

All good points. Whether an organization goes with times or points scoring there are many things to consider that would affect the scoring. There are bad ways of using either scoring method. I do think that the converse can also be said, that there are "fair" ways of using both, so an organization should examine the options and see what they can live with.

[MathGuy]

We still used a point system.

A few years ago we used points system, but we did measure the times. We raced 8 times and here shows the comparison of the Point Rank versus the Time Rank.

A few years ago this was the top 15 cars( of 29) results (just for our wolfs).

• Pt PR Total T Avg T T Rank
  45 1 19.650 2.456 1
  45 1 19.744 2.468 4
  44 3 19.651 2.456 2
  43 4 19.797 2.475 6
  42 5 19.861 2.483 9
  41 6 19.718 2.465 3
  40 7 19.810 2.476 7
  40 7 19.769 2.471 5
  37 9 20.170 2.521 11
  37 9 19.814 2.477 8
  34 11 19.894 2.487 10
  33 12 20.304 2.538 13
  32 13 20.437 2.555 14
  30 14 20.249 2.531 12
  28 15 20.537 2.567 17

Note the 3rd fastes car finished 6th in points, possibly because he got scheduled with some tough competition when he had poor lane selection.

I don't think the software that we used, had an optimal scheduling criteria like PN or PPN. So I look at this, and wonder what would be better, especially when there were some lane bias going on.

Now are the times "perfect". I don't know, but I know the race chair didn't publish times the next year. (That was wise. If you go times or points, don't let people know the results of the other, they makes it too easy for people to complain.)

If there are large Lane biases, my opinion time might the fairer way of running a race, that is if you do have the hardware/software, and a good starting gate.

[Derby Wizard]

We use time.

Why?
Simple to rotate cars through the lanes.
No one has argued a reason to switch to another format.

[Derby Wizard]

Absolutely. Starting gates that open quickly and cleanly are important for any derby. And they are clearly a prerequisite for any elapsed-time system, since there is no other way to measure the start time accurately enough for the results to be meaningful.

Our track uses the laser starting gate to start the time. It's positioned just down from the starting pin recess. The first car to trip it starts the time. It works pretty good. There are some slight variables that could come into play, but I believe its at least equal to other varibles with other starting gate mechanisms.

[Stan Pope]

Here is why Darin is correct, even with the down-track laser timer start:

Car A has an elevated nose; Car B has a low nose.

Suppose the gate is operated briskly. The gate leaves the cars more quickly than gravity can accelerate them. Both cars react to equal gravity from the starting line and reach the timer start sensor at about the same time and travel at about the same speed as they pass it.

Suppose the gate is operated less briskly in a way that the higher part of the gate moves away faster than car A can react but the lower part of the gate moves away more slowly than car B can react. Car A is accelerated from the top of the run from the full effects of gravity. Car B is accelerated less fully by gravity because the first part of its travel is encumbered by the starting pin. Thus Car B reaches the clock start sensor later and is traveling less rapidly that car A.

If you like timed races, please read the Cory's notes on his "experiments" page to see some other issues that you should address to avoid shorting some of the racers.

[PWTom]

We use points because we don't have a timer. We have a six-lane aluminimum track and race as a pack, more so than ranks or dens. This year we used a Stearns fragment to select the top 6 cars, then used a CPN chart to race the finalists. Very exciting racing in the finals.


Racing for time seems to take the sense of competition away from the race. You are racing the clock, not the other cars in your heat. What they do is not truly relative to your success. Also, racing for points yields more runs down the track. Each boy raced a minimum of 20 times in the Stearns frag, with the finalists going another 12. Lots of racing bang for all of the time that they put in building their cars.