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How many rounds of disc golf were played in 2020?
Using the Count the Sport surveys, my students and I attempted to estimate how many total rounds of disc golf were played in 2020. We focused on the proportion of all rounds recorded on UDisc. Once we had that estimate, we could invert the relationship and go from the rounds recorded on UDisc to the total number of rounds.
Through our analysis, detailed below, we estimated that about 50 million rounds of disc golf were played in 2020. You can see more statistics in UDisc's Disc Golf Growth Report.
Assumptions
Before fitting our model, we wanted to see if the ratio of recorded rounds depended on the following factors.
- Location – Are people in certain areas more likely to use UDisc?
- Day of the week
- Course ratings
- Weather
- Hole count – Are short courses (nine or fewer holes) different from longer ones (10 holes or more)?
Because the vast majority of our surveys and UDisc rounds were in the United States, we only checked our assumptions in the United States.
Those interested can read a detailed discussion of how we tested each assumption. But, in short, we found that weekends and weekdays were different, as were short and long courses, leading to four different subsets: weekday short, weekday long, weekend short, and weekend long.
There are other assumptions that we couldn’t test that may have an impact on the final results:
- Changes in the ratio throughout the year – We only have survey data for a two-week period in the fall. If the ratio is different in the summer or pre-COVID-19, that can impact the accuracy of the results.
- Changes in the ratio internationally – We didn’t have enough surveys from countries outside the U.S. to feel like we could make individual estimates. We did use the data we had to check if the ratios were at least reasonable and didn’t see anything too crazy.
Model
As we get into the details of our model, we’ll first define some symbols.
θ: The proportion of all rounds that are recorded on UDisc
ni: Total players in survey i
xi: Total UDisc-recorded rounds during the window of survey i
To incorporate uncertainty into that estimate, we use a Bayesian Beta-Binomial model:
θ ~ Beta(1,1)
θ|ni , xi ~ Beta(1 + Σxi, 1+Σni -Σxi )
Results
We found that, on average, one out of every five rounds of disc golf is recorded on UDisc. People more often record their rounds on weekends and/or on longer courses. The density estimates of the proportions are in the plot below.
Below are the results broken down by the four subsets mentioned earlier as well as divided into U.S. and non-U.S. categories.
Total Rounds of Disc Golf Logged in UDisc in 2020 |
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| U.S. Rounds | Non-U.S. Rounds | ||
| Weekday | Short Course | 781,447 | 465,104 |
| Weekday | Long Course | 3,730,217 | 1,578,790 |
| Weekend | Short Course | 452,183 | 286,584 |
| Weekend | Long Course | 2,837,808 | 1,000,537 |
Estimated Total Rounds of Disc Golf Played in 2020 (incl. 95% credible intervals) |
|||
| U.S. Rounds | Non-U.S.Rounds | ||
| Weekday | Short Course | 5.1 M (4.6 M - 5.6 M) |
3.0 M (2.8 M - 3.3 M) |
| Weekday | Long Course | 17.5 M (16.9 M - 18.2 M) |
7.4 M (7.1 M - 7.7 M) |
| Weekend | Short Course | 2.2 M (1.9 M - 2.5 M) |
1.4 M (1.2 M - 1.6 M) |
| Weekend | Long Course | 11.0 M (10.6 M - 11.4 M) |
3.9 M (3.7 M - 4.0 M) |
Based on these numbers, we estimated that 51.6 million rounds of disc golf were played in 2020 with 95% credible intervals between 48.5 and 54.6 million.
About the Authors
Brian Hartman (#19220) is an associate professor of statistics and actuarial program coordinator at Brigham Young University. He is better at statistics than disc golf though that is not saying much.
Brandon Brunner is a student at Brigham Young University studying Actuarial Science and will be graduating in December 2021. His brother-in-law got him into disc golf about three years ago and he loves trying to get more people interested in the sport.
McKay Christensen is a student in the Brigham Young University Master’s of Statistics program and will graduate in April 2022. He recently found disc golf through Brandon Brunner and has loved playing ever since.
McKay Gerratt is a graduate student in statistics attending Brigham Young University. He started playing disc golf with his brother in high school, but he really got into it with the extra time that the pandemic provided.