Pinewood Derby Stories and Photos from Maximum Velocity
Credibility of the Pinewood Derby Race
As a derby leader, I am very much aware of race credibility. Every participant in a derby wants to know that the race is completely fair, so the derby leader must take every precaution to ensure that there is no bias in the race. To the race participants, the race procedures must be above reproach.
Race bias can come in three ways:
- Intentional: A car or group of cars is unfairly treated by a race official (hopefully this never happens)
- Unintentional: A car or group of cars is unfairly treated due to poor race procedures
- Perceived: Even if all cars are in fact treated the same, a race participant or audience member can still believe that an entry is being treated unfairly.
To run a race with integrity, the derby leader must make every effort to eliminate all of these forms of bias. Below are guidelines you can follow to keep your race above reproach. Remember that the goal is not just to eliminate race bias, but to also eliminate any perception of bias by the audience and participants.
Complete - The race rules must be complete. Thus, the rules should specify all car dimensions (maximum height, maximum overall width, minimum distance between the left and right wheels, maximum length, bottom clearance, wheel base); and allowed/disallowed wheel treatments, axle treatments, accessories, and weighting methods.
Specific - If the intent of your rules is to ban specific design techniques, then the rules must specifically do so. If the rules do not specifically ban a particular technique, then entries using that technique should be allowed to participate. For example, consider the following rules:
1. A light sanding to remove flaws is allowed as long as the wheel retains the original width, diameter, and shape.
2. The wheels may be lightly sanded.
Rule 1 is very specific as to what can be done with the wheels. A car with narrow wheels would clearly be disqualified from a race using this rule.
On the other hand, rule 2 is ambiguous and could lead to problems. A car with narrow wheels should be allowed to participate, since the rule does not disallow narrow wheels.
As an example of the need for complete and specific rules, one person wrote to me stating that they wanted to remove material from the wheels. This particular technique was not mentioned in their rules, so they asked a race official (not the head official) if the technique was allowed. The race official gave them permission. But at the weigh-in, the head official disallowed the technique, and the car was banned from the race. This was clearly a case of unintentional bias (hopefully it was not intentional), and could have easily been eliminated with clearly written rules.
Dual Officials - Since race officials typically are the parents of one of the entrants, always have two officials perform the car inspection, including weighing the cars. These two officials must not be related to each other.
Official Weighing Method - Regardless of the type of scale you use, make sure that all cars are weighed on the same scale, and that the method of weighing is consistent for all cars. With our postal scale, instances have occurred where the scale display alternated between 5.0 and 5.1 ounces. So, our policy is that the scale must consistently show 5.0 ounces or under for 5 seconds before the car's weight is consider official.
Scale Location - Locate the official scale on a solid surface, away from any air ducts. Both airflow and a shaky surface can affect the readings on sensitive scales.
As an example of this problem, during one check-in our scale was located under an air-conditioning duct. Whenever airflow was present, the scale would read a slightly greater weight! Once we realized the problem, we covered the duct. But we had to reweigh all of the cars to make sure that everything was fair.
If your check-in occurs immediately prior to your race, then storage is not an issue. But in some races the race evening is shortened by holding the check-in on a prior night. The cars are then stored until the race.
To ensure that our race is above reproach, two non-related officials store the cars, and then put a 'seal' on the storage area. On the night of the race, the same two officials check to make sure the seal is not broken. The 'seal' can be as simple as an adhesive label placed across the opening of the storage cabinet. The two race officials then initial the seal.
This process may seem excessive to you, but if a parent ever asks how we ensure that no tampering occurs while the cars are stored, we are ready with a good answer.
Race formats can also introduce bias. We will be covering race formats in much greater detail in future articles, however here are some basics.
Elimination Method - Elimination methods can accurately determine the fastest cars if the number of lanes is taken into account. With a two-lane track, a double elimination method can only determine the top two cars, not the top three (the third fastest car could get eliminated early by racing the fastest car and then the second fastest car). So with a two-lane track, third place must be determined by rerunning all eliminated cars. With a three or four-lane track, third place can be determined as long as the top two cars in each heat 'win', and the third and fourth place cars (on a four-lane track) 'lose'.
Stearns Method - Stearns and other rotational methods are good at finding a group of the fastest cars, but cannot guarantee the trophy winners unless all cars race all other cars an equal number of times and with equal lane use. For a small number of cars, the Stearns method can work well. But for a large entry field, the Stearns method could take a prohibitive amount of time to determine the winners. In our race, we resolved this by using Stearns to identify the top group of cars, and then follow with a double elimination to determine the trophy winners.
Lane Bias - Generally, one or more lanes on a given track are 'fast', while one or more lanes are 'slow'. Thus, with any race method, it is important to randomize/equalize lane use. With Stearns and other rotational methods, lane assignments are randomized or rotated. But with Elimination methods, care must be taken to randomize lane assignments. One way to do this is to have the entrants draw lots for the lane assignment prior to each heat.
One of the worse things that can happen in a race is for a child to drop their car. But even worse is for one of the race officials to drop (or even mishandle) a car! Thus, use a race procedure whereby the officials rarely if ever touch one of the cars. This means that each car owner picks up their own car from the staging area, places the car on the track, and then returns the car to the staging area at the end of the race. In the case of very young or disabled car owners, parents or a sibling can take on the car handling responsibility.
Manual Judging - Clearly, if an electronic finish line is not available, then two non-related judges must judge the races. The judges must agree on each finish, or the race must be re-run. If one of the officials misses the finish or cannot distinguish the winner, then rerun the heat. Don't allow one judge to defer to the other.
Electronic Judging - For finish lines that display the results to the audience, no special precaution is required. However, some finish lines display the results on a remote module, or directly enter the results into a computer. In any case where the results are not instantly displayed to the audience, two non-related judges must monitor the results.
I realize that to implement all of the above mentioned precautions will take extra work on the part of the race official. However, you must ask yourself one question. If a parent came to me and said, "My child's car is being treated unfairly," what would you say? If you have implemented all of the precautions above, you can ask the person to clarify, and then explain how the precautions you have taken ensure that each entry is treated fairly. But if you have not implemented all of the precautions, ...