NACSW uses a random draw to select dog-handler teams for each trial. A random draw involves selecting teams by chance, much like drawing names from a hat. NACSW uses the Excel random number function to select teams which provides both fairness and convenience.
Sometimes people ask why, after entering so many trials, they did not get into any (or only got into 1 or 2). Sometimes people claim that the system is “rigged” or weighted to reward certain individuals. Because of the confusion and concerns about fairness, we wanted to provide a layperson’s guide to how NACSW random draws work and a miniature introduction to how probabilities work.
We often get asked why we do not allocate spaces based on the number of times a team has been wait listed or how many trial opportunities they have had. With 6,897 members for the 2019-2020 membership year and 535 trials in 2019, it would be very difficult to track each individual team, count how many trials they were in or how many times they were wait listed and give them higher/lower priority for any particular trial. There are many factors that complicate this including that people enter many trials simultaneously and often move off the wait list into a trial which would then affect their status for other trials that have already completed the draws.
For any given draw, your chance of getting into a trial depends on the number of people who entered (plus the number of people with additional draws). For example, if in Trial A 100 people entered and there are 40 slots available, you have a 40% chance of getting into that trial (or you can think of it as a 2 in 5 chance).
Each trial draw is independent of any other trial draw. This means that your chance of getting into one trial is separate from your chance of getting into another trial. We do each of the draws separately, except under specific circumstances (such as linked trials with 2 days of NW3 at two different locations). So if in Trial A from above you have a 40% chance of getting in, but in Trial B there are 200 people entered and there are 40 slots available, you have a 20% chance of getting into Trial B (or 1 in 5). Therefore, getting into (or not) Trial A has no relationship to getting into Trial B.
Because each trial draw is independent of each other, there is the chance you can get into all the trials you enter, none of the trials you enter, or some of the trials you enter. As you enter more trials, it would be rare that you got into none (or all), but it could happen.
For those readers not interested in statistics, you can take this on faith and stop reading. For those interested in delving into this more, keep reading.
When using random draws, the data (in this case number of trials you get into) tend to resemble a “bell curve,” or what statisticians call “normally distributed.” To explain what that means, let’s take sets of 100 coin flips as an example, and you are going to do a lot of sets, like 2000 sets. In one set of 100 coin flips, you may get 50 heads, 50 tails; in another you may get 25 heads, 75 tails; and in another you may get 10 heads, 90 tails; and in another 0 heads, 100 tails.
This coin flipping goes on until your flipping thumb gets really tired. If you were to record these 2000 sets of 100 and plot them, you would find that half the time you get 50 heads, 50 tails, fairly often you’d get 45 heads, 65 tails, and rarely 10 heads, 90 tails. Even more rarely (or darned near impossible!), you would get all 100 tails.
How does this relate to getting into trials? Let’s look at a hypothetical example where all the trials you enter have 35 spaces and there are 70 entries. The odds of getting in are 50%. You could be the average person and get in about half the time; you could be slightly above average and get into more than half. You could be slightly below average and get into fewer than half. You could be a unicorn and get into every trial. Or, you could be the womp-womp and get into none in a given year. Over time as you enter more trials, it is likely (but not guaranteed) that you will move towards the average. The diagram below shows the distribution of people getting into none, fewer than half, half, more than half, and all the trials with a “normal distribution.”
Exhibit 1. Distribution of Getting into Trials
NACSW values fairness and strives to put fairness into practice. We know how disappointing it is to be waitlisted and waitlisted again.
If you are interested in helping to create more trial opportunities, reach out to hosts in your area to see how you can support them. Or if you are interested in hosting a trial yourself, email firstname.lastname@example.org
We very much appreciate the community of people who participate in our events. We love seeing their love of their dogs and the sport and seeing everyone support each other.
Thanks to Heather Kane for creating this document.