Estimating Scores for Holes Not Played – Another Bad Idea from the World Handicap System

 The trouble with the World Handicap System (WHS ) it that its administrators do not know how to leave well enough alone. Too often the WHS confuses motion with progress.  Case in point is how a “hole not played” is now scored for handicap purposes.   Prior to 2024, if a hole was not played the player simply entered a net par.  It could be argued that the net par procedure is unfair.  For example, if the stroke allocation of a par five is 13, all players with a handicap between 0 and 12 would record a 5.  In actuality, however, the 12 handicap is likely to have a higher score than the 0 handicap.   To correct this inequity the WHS adopted a procedure for holes not played as summarized below.

1. An expected Score Differential for the hole or holes not played is calculated, based on a given Handicap Index and a course of standard difficulty. The expected score is based on the average Score Differential of a player with a given Handicap Index and a normal distribution of scores – so it is not specific to each player.
2. A Score Differential for the holes played is calculated using the player’s actual scores and the rating value of the holes played.
3. The Score Differential from the holes played is combined with the expected Score Differential to produce either a 9-hole or 18-hole Score Differential.

To use this procedure, a player must enter all of his scores on holes played which is both time consuming and laborious.   The WHS argues that this procedure will lead to more accurate Handicap Indexes.  The WHS, however, does not supply any evidence for this claim.   

To examine the claim of increased accuracy, the estimated hole score is compared with the net par score to see if there is a significant difference between the two.   The WHS does not give a clear example of how the missing hole score is estimated.  For the purposes here the Estimated Hole Score is found by the following formula:[1]

Estimated Hole Score = (WHS Differential) x (Slope Rating/113) +(Course Rating - S17)

Where,

              S17= Player’s score on the 17 holes played

A small sample of scores from a tournament where a par five with a stroke allocation of 13 was out of play is used.  The expected score[2] and the net par scorer are shown in Table 1 below:

Table 1

Estimate Hole Score Versus Net Par

Player’s Index	Course Ratings	Net Par	Estimated Hole Score
7.1	70.0/124	5	5.0
7.7	71.2/127	5	5.2
12.0	70.0/124	5	5.4
16.4	70.0/124	6	5.7
19.9	68.4/120	6	5.7
38.0	70.3/124	7	7.2

 

While the sample is small, it does show that the estimated hole score from the same set of tees does increase with a player’s Handicap Index.  It also shows, however that there is usually a small difference between the Net Par Score and the Estimated Hole Score.

What is important is how the Estimated Score affects a player’s Handicap Differential in comparison with the Net Par Score.  Table 2 below shows the Handicap Differential using the WHS Estimated Score and the Net Par Score.  

Table 2

Handicap Differential for WHS Estimated Score and Net Par Score

Player’s Index	WHS Diff.	Net Par Diff.	WHS – Net Par
7.1	4.6	4.6	.0
7.7	6.2	5.8	.4
12.0	12.2	11.8	.3
16.4	13.4	13.7	-.3
19.9	16.3	16.6	-.3
38.0	37.3	37.1	.2

 

There appears to be little difference in the Handicap Differential between the two procedures.  If the score was not among the best 8 of 20 scores, both procedures would have the same effect on a player’s Handicap Index—none.  If it was among the best differentials, the largest effect among the six players caused by the WHS procedure would be to increase a player’s Handicap Index by 0.1 (.4/8 round up) at most.

The WHS was probably forced to adopt the Estimated Hole Score since it adopted the Estimated Nine-hole Score—another bad idea (see www.ongolfhandicaps.com, The World Handicap System Predicts Future Performance, January 25, 2025.  The thinking would be along the lines that if the WHS can predict the scores on nine holes, it would be inconsistent to believe it could not predict the score on one hole.

Is such a small difference in a Player’s Handicap worth the effort?  The WHS should present evidence that the estimated hole procedure is more equitable.  It should also present a research paper describing the statistical theory behind the theory.  The WHS has a tradition of not making its research public to avoid peer review.  It relies on the golf community to believe in the omnipotence of its decisions.  It has worked so far.

---

[1] This formula produces the differential shown in a player’s GHIN file.  It is not clear how the WHS actually calculates the Estimated Hole Score.

 

How Good a Golfer is President Trump?

When asked by a reporter what his handicap was, President Trump responded, “very low.”    For a man whose use of superlatives is typically excessive, his reply could be viewed as both modest and vague.  The reporter did not know that handicaps vary by golf course and by the tee set selected. This means a player of moderate ability could have a low handicap (e.g., a player with a 10.0 Handicap Index would have a 5 Course Handicap from the red tees at Trump National, Jupiter).  So how good is the President?  There are three ways to evaluate his skill level: swing analysis, posted scores, and eyewitness testimony.

Swing Analysis - The President has posted a video of his swing on Truth Social.  To the casual observer, the swing looks like a before picture on a YouTube instructional video.  You can almost hear the YouTube analyst saying “the President takes his club too far inside which prevents the club from getting past shoulder high.  This can be fixed by purchasing and following my Five Steps to Winning Golf.”  Admittedly, there are some unorthodox swings (Jim Furyk, Lee Trevino, and Moe Norman) that have been very successful.  Maybe the President’s swing fall into that category, but that would take a leap of faith.

Posted Scores - The posted scores of a player can be found on United States Golf Association’s Golf Handicap Information Network (GHIN).   The President (or more correctly the Trump Organization) owns golf courses in New Jersey, New York, California, Washington D, C., Florida, Pennsylvania, and North Carolina.  The President does not maintain a Handicap Index in California, Pennsylvania, North Carolia, Washington D.C or Florida.  The absence of a Florida Handicap Index is curious since Eric, Ivanka, and Kai Trump have Index files at Trump National in Jupiter Florida.  It is all the more puzzling since the President has bragged of recently winning the Senior Club Championship at this course.

The President does maintain a handicap under the same GHIN number at Winged Foot in New York and the National Golf Club in New Jersey.  His Handicap Index is listed as 2.5.  This would be impressive except for the President not posting a score since 6/2021 and the fact that his eight best scores (i.e. those used in calculating his Handicap Index) were posted between 2011 and 2016.  

Eyewitness Testimony – There are many who have played golf with the President but have wisely remained mum or non-judgmental about his game.  John Daly said the President had a decent game but that could mean about anything.  A press pool reporter is assigned to follow the President when he plays golf.  That reporter is probably told to restrict coverage to assassination attempts and not include the President’s score.  The members at the Jupiter Club must have a good idea of the President’s prowess—especially those members he allegedly defeated on his way to the Senior Club Championship.  Perhaps because they value continued membership in the club, defeated members have also chosen to remain silent.   

Conclusion –. There are three conclusions that can be drawn: 1) The President’s failure to post scores makes his claim of a low handicap suspect and impossible to verify, 2) The President was an accomplished golfer ten years ago, and 3).  History will not judge the President on his Handicap Index, so his self-evaluation of his golfing ability is of little importance.

World Handicap System 2024: A Change in Handicapping Four-Ball Match Play

The World Handicap System made a change in the method for determining four-ball match play handicap. Previously, each player was assigned 90 percent of his handicap.  A player’s playing handicap was then this handicap minus the handicap of the player with the lowest handicap. The method is illustrated in Table 1 below using the example presented in WHS 2024 Rule 7 Guidance:

The new method is more complicated.  First a player’s unrounded handicap for each player is calculated 15.353 for player B).  Second, each player is then assigned the unrounded difference between his unrounded handicap and that of the player with the lowest handicap (16.486 for Player B). Third, the ninety percent allowance is applied to the unrounded difference (14.838 for Player B).  Fourth, the unrounded difference is rounded to form the playing handicap (15 for Player B).  The results are shown in Table 2 below:

As shown in the tables, the new method makes little change in playing handicaps.  A player may get one stroke more or less depending on the random nature of rounding.  This is illustrated by two examples presented in the Appendix.  Minimizing the number of rounding procedures in determining handicaps is a good thing.  It will have a noticeable positive effect on handicaps for foursome and Chapman events.  This point was made years ago in a recommendation to the USGA (See, www.ongolfhandicaps.com, Chapman Handicaps and Sec. 3-5: Proposed Changes in Allowance, August 19, 2013).  The WHS is to be commended for making the change even if belated.

The examples shown are for players using the same tees.  The WHS implies the new handicap system ensures the equity of competition.  Actually, it gives players a chance to game the system.   For example, take two players with18 handicaps.  The 90% a;;pwance would reduce their handicaps by two strokes.  If a player moves to the forward tees, his handicap is 14 and his handicap is only reduced by one stroke.  This would give him a slight advantage over the player who plays the back tees.  This is one reason (others are errors in course ratings and incorrect placement of tees) why this blog has always recommended players play from the same set of tees in competition.  This recommendation is generally disregarded so the reader should be aware of the possible defects in equity. 

                                                                          Appendix

                                                   Examples of the Change in Handicaps 

The 2024 World Handicap System: Predicting Future Performance

 

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

                                                         Error Estimates for 2024 WHS