124th U.S. Open

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How to catch a sandbagger

The computer algorithm that has tournament cheats on the run
May 09, 2023

George Thurner remembers the phone call. The handicap chair of a prominent golf club reached out to him after the same player won all three of the major handicap events for two straight years. The club couldn’t figure out how this accountant in his mid-50s was gaming the system. He was turning in all his scores, and the handicap committee checked with those he played with to make sure those scores were accurate. Still, he kept winning.

Although the club’s handicap committee could not solve the issue, Thurner’s “Cap Patrol” algorithm figured it out quickly. Comparing the scores revealed that others in his group always posted scores from the back tees, but the player in question always posted from the most forward tees—a 3.2-shot difference. “The club banned him from all events for life once the information was verified,” Thurner says. “He ended up leaving the club.”

We likely all know this kind of player: the golfer who always comes up big in net events. The talk varies from hushed whispers to outrage, but it revolves around a single word: sandbagger. That talk is habitually accompanied with a sense of resignation, along the lines of, “Dammit, Bill wins all the time, but what can we do about it?

It’s why Thurner created Cap Patrol. The algorithm-based software program syncs with the U.S. Golf Association’s Golf Handicap Information Network (GHIN) and course tee sheets and uses 43 data points over five primary criteria: Handicap Index during the past 12 months, home scores versus away scores, potential of the player, percentage of scores turned in and tournament finishes. Cap Patrol puts those numbers in a data blender and then recommends which handicaps need to be adjusted (and by how many strokes), as well as who to keep an eye on and who to leave alone.

Peer review is an integral part. If player A and player B are playing together, each receives a notification the next day detailing what score the other player turned in and from what tees. If player A shot a 79 but turned in an 82, player B will know that and be able to report it via the anonymous red flag feature on the app. In short, the system helps keep everybody honest. Besides catching sandbaggers, Cap Patrol identifies vanity handicaps and can recommend an adjustment up.


The system—currently used by 1,100 clubs and courses covering more than 620,000 golfers—was conceived by Thurner, a self-described data nerd from Cincinnati with a background in sports analytics. A member at Cincinnati’s Hyde Park Golf & Country Club, Thurner sports a 0.4 Handicap Index and has served in several board positions, including club president, golf chairman and handicap chairman. “I’ve heard every sandbagging story imaginable,” he says. “I was sick and tired of six to eight people at many clubs ruining the biggest events. I wanted to build something that took personality out of it, was data-driven and helped courses deal with this issue.”

The sandbagger maneuvers the GHIN system like a NASCAR driver navigating Daytona Speedway, knowing when to throttle back and when to hit the gas. These players know that posting a 78 is OK if a 74 is getting knocked out. Or they might post a score higher than what they shot when playing with partners who are relatively oblivious. They might also exploit the opportunity for a higher-than-normal “away” score at another course if verification is unlikely. Some freely add a stroke here or a few strokes there to their actual number or omit a handicap-damaging low score. “Some players never miss an opportunity to post a bad number,” Thurner says.


However, one number can’t be fudged, nudged or otherwise manipulated: tournament finishes. According to Thurner, the USGA and others have done significant research on how often a player should make the winner’s podium. Golfers playing in a normal number of events (defined as eight during a two-year period) should place first no more than once and may have one other high finish, such as fourth place, in that eight-event span. Anything beyond that is not statistically reasonable.

The same people winning over and over not only creates a bad club vibe but can have a damaging effect on event participation. “Most clubs know who these people are,” Thurner says. “They just don’t know how to prove it.”

Cary Cozby, head professional at Southern Hills Country Club in Tulsa, remembers receiving a call from Devin Gee, head professional at Oakmont Country Club, an early adopter of Cap Patrol. “He encouraged me to spend time looking at it,” Cozby says. Southern Hills has 812 members in its GHIN system, yet the club has had fewer adjustments than some others. (Thurner estimates 2 to 4 percent of all players need adjusting.) “We look at the reports twice a month,” Cozby says. “We’ve only had five or six adjustments in three years, but we have one member who has been adjusted multiple times. He even mentioned after one win, ‘I’m so screwed now with Cap Patrol.’ After looking at our most recent report, he is going to get knocked down another stroke plus.”

With a more level playing field comes, hopefully, increased participation and a wider group of golfers winning. Thurner says his data shows that clubs using Cap Patrol average 55 percent more winners. If all of this sounds a little like George Orwell’s Big Brother, well, that’s the point. Thurner cites one player who won five events during a single season and played 25 percent better in tournaments than in casual rounds. However, according to Cap Patrol data, less than 2 percent of golfers play better in tournament rounds compared with casual rounds. Any golfer playing consistently more than 5 percent better in tournament rounds is statistically questionable, Thurner says.


Cap Patrol strives to be objective and take personality out of the equation, but the reality is anyone tagged for an adjustment is going to require a conversation, one that can be awkward. “We hear ‘This is unfair. You guys are picking on me.’ ” Cozby says. “But it’s the opposite. It’s based on data. It also helps the behavior of everyone else. Members hear a few guys get adjusted, and it makes them more aware of things such as how to properly post scores when matches end. We’ve seen an uptick in posting scores and doing so properly.”

In fact, says Thurner, his data reveals that clubs using Cap Patrol for just one year experience a significant uptick in the percentage of scores posted, jumping from 60 percent pre-Cap Patrol to 86 percent afterward. Although a club and its committee receive a detailed deep dive that truly peels back the curtain on scoring, posting, trends and tournament finishes, all members receive free access to the Cap Patrol app. Some of the data is sure to lead to ribbing on the patio, but the app is meant to be more entertainment than accusatory.

The app features a Hot Gauge that indicates if you’re currently ice cold, on fire or somewhere between. It calculates your clutch percentage (basically how you play in tournaments versus everyday play) and how you’re trending. The app also provides a real-time club ranking of how you’re faring against the rest of the club. You can also look up similar data on every other player at the club (but with no access to data from players at other clubs). Nowhere does it indicate whether you’re looking at an adjustment or not.

Perhaps the most entertaining feature is the odds section, which calculates the probability of a certain handicap shooting a certain score. For example, a 72 shot by a 10-handicapper should happen once every 194 years, according to the USGA probability table. Anything over once every 16 years is beyond reasonable. The USGA allows Cap Patrol to use its probability statistics in the Cap Patrol app, but there’s no formal partnership between the two.

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The app has more useful purposes, too. If you’re looking for a partner for an event, you can go to the partners section, and it lists every member with a handicap and color codes them red, orange, yellow, light blue, dark blue. Those in red probably have their text messages blowing up. Those in dark blue likely hear crickets.

Instead of throwing balls in the air or twirling a tee to decide teams for a friendly match, a matchup feature looks at each player’s information and will calculate the most evenly matched teams for the day. Members of clubs tired of the “blind draw” events that always seem to have a few stacked teams can use the option for entering as many as 120 players and having the app figure out the most evenly matched foursomes for that tournament. According to Thurner, additional features are still to come, including one that will track pace of play and note who plays quickly and who is pokey. All that is nice, but the key feature—stopping sandbagging—remains central to the reasons for implementing the system.


One 100 Greatest private course in the Midwest has some 1,100 members in the GHIN system. “We have a very big member-guest event, and we had two members and their guests that just ran away with the tournament the past few years,” said the handicap chairman. “When you’re playing well and winning, your Handicap Index should be going down. It usually does go down, but for some, right before the next tournament, it goes right back up. Often, it’s the same people. I don’t want to be the hall monitor at my club. I just want a level playing field for everyone.”

The club adjusted seven people in one month. The point was made. In the two years since, they have not had a runaway winner in any event—not that such parity makes everyone happy.

“I hear a lot of protests along the lines of ‘But I’m a gamer’ or ‘I focus more on tournaments,’ ” Thurner says. “When I hear that, and they’ve been winning, what they’re really saying is that their everyday Index is not reflective of their ability, which is what the USGA system is based off. I just respond, ‘I couldn’t agree with you more. That’s why we’re adjusting your Index to where it should be.’ ”

As Cozby says, “It’s uncanny how good this system is at identifying those that need to be adjusted. Normally the thieves are ahead of the good guys. This changes that.”

Wesley Turner, handicap chairman at Metairie Country Club in Louisiana, puts it bluntly. “The worst call I get is when members say they’re not playing in an event because so and so is playing, and I know their handicap is not legit,” he says. “The next worst is when they’re playing a match and are calling me from the third hole to already complain about someone’s number. Those situations help no one. We have had several events lately with better participation because of Cap Patrol. It takes a while to get member buy-in, but once you do, it’s truly for the benefit of everyone.”

So what does it cost? The current offer is a 60-day free trial. If the club decides to move forward, the annual fee is $6 per player Index with a max price of $3,600 if a club has more than 600 members. As one pro said, “We’ve had this hornet’s nest hanging by the golf shop for a long time. Now it’s finally time to take care of it. It’s a little painful at first, but once it’s gone, things are so much better.”

Put another way, Bill is no longer going to be winning all the time.