Introduction -The treatment of 9-hole scores was changed under the 2024 World Handicap System. Under the new procedure, a player’s 9-hole differential is added to his “expected” differential to make an 18-hole differential. In reviewing this change, this post takes a two-prong approach. First it examines the arguments put forward in support of the change and finds them lacking in substance and validity. Second, it details the downsides of the change. It is found that the new procedure promotes sandbagging and leads to inaccurate estimates of a player’s Handicap Index.
Argument for the Change – The WHS arguments in support of the change are presented in WHS 2024: Treatment of 9-hole Scores which can be found at the USGA website.
Argument 1 -The change benefits the many players who regularly play and post 9-holesrounds because it is more responsive. Players will no longer have to wait for another 9-hole score to be posted for an 18-hole Score Differential to be calculated.
If a player regularly plays 9-holes, how long could the wait be? Would it not be better to wait a week to have a player’s Index be based on actual scores rather than an estimate of what he might score?
Argument 2 -This change provides a better indicator of how a player will normally perform over 18 holes on a given day when compared to combining 9-hole scores from different days and under different playing conditions?
The WHS has not presented any research to validate this assumption. It appears a player’s second nine differential is estimated at 60 percent of his Handicap Index. That is, regardless of course difficulty or playing conditions the estimate of the second nine Handicap Differential is always the same. The WHS apparently believes the Handicap System (Course Rating, Slope Rating, and Playing Condition Adjustment) is just not up to the job of measuring a golfer’s performance.
Argument 3 -This new method produces a more consistent and comparable Handicap Index for those who post 9-hole scores.
Prior to 2024, the order in which 9-hole scores were combined could add to the volatility to the Handicap Index.
It was also common for two good scores to combine to produce an 18-hole Differential which was lower than any of the Score Differentials based on an 18-hole score in the player’s scoring record which resulted in a Handicap Index that may be difficult for the player to play to.
The order of combining 9-hole scores was straightforward as described in Rule 5.1b. The order could not be manipulated as suggested in a video defending the change. Competition 9-hole scores should not be combined with non-competition 9-hole scores. The WHS never made that stipulation as the WHS makes no distinction between those two types of scores.
The argument that it was common for combined 9-hole scores to be lower than any 18-hole differential is unsubstantiated and probably not true. It is true that really good 18-hole scores can result in a Handicap Index that is difficult to play to (see Rule 5.9). Does the WHS suggest the good scores be adjusted upward so the player remains competitive? Probably not.
Downsides - Now let’s examine the downside of the change.
Downside 1 – Not an accurate indication of ability when used in 9-hole tournaments.
There are tournaments where players play 9-hole matches. One example would be where players play two matches on the first two days and one match on the third day. Under the WHS change in treatment of 9-hole scores, it is almost impossible for a player to get an exceptional score. Assume a player with 14.8 Handicap Index had two 38s. He would be assigned two rounds with a 13.1 differential based on the Course and Slope Ratings. record. Prior to 2024, his 9-hole scores would be combined, and he would receive a 6.9 Handicap Differential. This would subject the player to a penalty under Rule 5.9. Under the 2024 WHS, the player escapes any penalty. The history of handicapping shows a long and extensive search to create a system that eliminates sandbagging. The 2024 WHS goes in the opposite direction.
Downside 2 – WHS estimates of second nine performance are not accurate.
The WHS estimates how a player would score on his second nine. Using tournament data (see Appendix), WHS estimates were compared with a player’s actual performance. The errors ranged from +5.1 to -5.2. If a player posted a score with such an error, he would be hauled in front of the Handicap Committee. The WHS, however, grants him a pardon for errors that are no fault of his own.
Downside 3 – Handicap Indexes based on phantom scores.
A 9-hole player will have his Index decided by nine actual rounds and nine phantom rounds provided by the WHS. Will there come a time when a player does not actually have to play, but can rely on the WHS to estimate what he would have scored if he had played?
Downside 4 – Another bonus for the sandbagger.
If a sandbagger is trying to eliminate a great score, he can post his round in 9-hole increments. That would allow him to play 10 18-hole rounds instead of 20 to clear his scoring record. If asked by the handicap committee, he could argue he changed putters between rounds that made for two 9-hole stipulated rounds.
Conclusion - So why did the WHS make the change? It could be the handicap officials at the WHS are trying to justify their existence. If there is no change, why do we need them. It could be hubris as the analytical staff wants to convince players of their omnipotence --i.e., we can predict your score without you lifting a club. Neither is a good reason.
Appendix
A player plays two 9-hole rounds (1-Nine and 2-Nine). Using a player’s Handicap Index, the WHS predicts the score of the player on the second nine. The difference between the player’s actual 2-Nine score and the WHS estimate of his 2-Nine was found as follows:
The first player in the table below is used as an example. The WHS assigns an estimated 18-hole differential of 8.8. This means his estimated 18-hole score is:
Estimated 18-hole score = 8.8 x (Slope Rating/113) + Course Rating.
With a Slope Rating of 122 and a Course Rating of 69.6, the player’s estimated 18-hole score is 79.1. The player scored 39 on 1-Nine so the WHS estimate of 2-Nine is 40.1 (79 -39). The error is the difference between the actual 2-Nine and the estimated 2-Nine score or 5.1 (40.1-35). The errors range from +5.1 to -5.2. Apparently the WHS believes such error rates are acceptable.
Table
