The Australian Golf Handicap System

Transcription

1 The Australian Golf Handicap System Executive Summary A number of theories and suggestions have been put forward in response the first nine months of competition under the handicap system. Using a sample of one million rounds of golf from the GolfLink system, for over 27,000 competitions involving over 0,000 golfers, an analysis has been completed which provides answers the following suggestions and questions. Higher markers do indeed exhibit a greater scoring standard deviation than do low markers. As it is not uncommon for a score be two standard deviations from the mean, it should not be uncommon for a scratch golfer vary by 89 strokes from his mean, and for a high marker vary by up 16 strokes for men, 18 for women. But the low marker is having this deviation added a higher mean than the high marker: it turns out that the Top scores only vary by two three strokes across handicap groups. Under the system, a higher marker was less likely play their handicap on a given day than was a lower marker. en: 7.4% chance v.% chance; omen:.3% v.0%. This holds true under the system but a lesser degree. en:.9% v 21.3%; omen: 7.6% v 17.6%. It was suggested that under the system and the system, the low marker will be advantaged in very small fields. In fact the data shows that there was no small field size advantage for the low marker under the system. There is however under the system. The low marker does find it harder compete as the field size increases. Under the system, the field size value at which a low marker is disadvantaged is about 0 for men, 0 for women. They do still compete and are winning competitions at very high field sizes, but the chances of them winning will be lower than occurred with the system. So prize patterns do vary depending on the field size, but differently at different handicap levels. Under the system, there was a significant advantage the low markers, which actually grew with field size. Consider first the en s competitions under the system. A method of describing advantage is developed in the analysis that follows, and called Handicap Bias. Under the system the Playing Field was significantly lifted at one end in favour of the low markers. In this style of chart, the 0% level is neutral, over 0% is a favourable bias, while under 0% is an unfavourable bias. The lowest markers are the dark blue bars rising at the back. But even the red bars rise significantly for the 1 markers. Handicap Bias en System 0.0% 0.0% 0.0% 0.0% 0.0% The Australian Golf Handicap System Page 1

2 Under the system the Playing Field is more level, but there are some bumps and variations that disadvantage the lower markers and advantage the higher markers at higher field sizes. Note the low markers are in the foreground here so that they are better seen. One can see the high markers rising with field size at the back. The bumpy nature of the 0 markers can be attributed the fact that they represent only 0.% of the field, and the numbers in the sample are o small give a smooth ride. Handicap Bias en System 0.0% 0.0% 0.0% 0.0% 0.0% The number of players in the above chart is as follows. It is clear that most are competing under larger fields. Distribution of Field en System,000,000,000,000,000,000,000,000, The Australian Golf Handicap System Page 2

3 For the omen s competitions, a somewhat similar pattern is evident. Under the system, there was a significant advantage the low markers, 1, which actually grew with field size. From 11 the trend reversed, was neutral in the s, and again rose with field size in the s. Handicap Bias omen System 0.0% 0.0% 0.0% 0.0% 0.0% Under the system, the very low markers do not seem be as disadvantaged as they were for the men. There is still a marked disadvantage 16 handicap players at larger field sizes. Handicap Bias omen System 0.0% 0.0% 0.0% 0.0% 0.0% The distribution for the chart above is as follow. It is clear that unlike the men, most women are playing in the smaller field size area, off higher handicaps, where the changes are not so extreme. Distribution of Field omen System 8,000 6,000 4,000 2, The Australian Golf Handicap System Page 3

4 So is the system equitable for small fields but not for large fields? There is still a small favourable Handicap Bias wards the low markers at field sizes up 0 for men, 0 for women. Over this the bias becomes more and more unfavourable for the low markers and favourable for the high markers. Is a score sample large enough accurately reflect the scoring potential of an inconsistent player? If we were use a sample (taking the best scores) vs the current sample (taking the ten best scores), the average variation at low handicaps is negligible, rising a one stroke reduction in handicap at the highest handicap levels: Impact of using v Rounds Average of Calc Average of Calc However what is essentially a period moving average responds more slowly changes in performance than does a period moving average. This means that on a period sample, handicap relief when form deteriorates will be less than for a. However the flip side of this coin is that after improvement, the period sample will also respond more slowly this improvement in form. So if there has been a slump from which there has been a recovery, the improved form will benefit from the higher handicap longer than it will under a sample. Is it feasible that a highmarker will endure an extended run of poor scores resulting in a handicap which is not relevant their scoring potential? It is possible that players can have a run of poor scores, which inflates their handicap, followed by an excellent score. Defining a Turnaround as achieving a score of or more, where the average of their last rounds is or less, there has been some increase of these Turnarounds. Over all they represent 1% of all rounds, compared 0.% under the system. Turnaround Rounds as a % of All Rounds. 4.0% 3.0% 2.0% 1.0% The Australian Golf Handicap System Page 4

5 The occasions when this Turnaround leads a in has also increased, overall from 0.% 0.46%. 2.0% 1.% 1.0% 0.% Turnaround & in Rounds as a % of All Rounds Thus, yes, markers over can have a run of poor rounds and then a very good round. But the Turnaround and in scenario accounts for less than one half of one percent of the rounds. Is it likely that large fields will exhibit enough players in such a situation that the challenge of the low marker becomes further extended a material extent? The challenge low markers, as discussed above, already includes any impact of Turnarounds. In other words, the challenge is as already measured, and includes any impact of Turnarounds. To what extent would using a forty rather than twenty sample impact Turnarounds? Impact of v Sample System on Turnaround Golfers Prior Rounds Turnaround Day Rounds Later The golfers who have experienced this Turnaround were compared and their handicaps averaged. One can see how the handicap rose by about two strokes under the system, and a little less, one 1½ strokes under the systems, on the day they had the Turnaround. In the case of the system, the handicap has fallen, almost back what it was on average, ten rounds later. But in the case of the system, it is still one two strokes higher than it was. The Australian Golf Handicap System Page

6 hat have been the changes in competition patterns between the system and the system? hat handicaps are winning competitions? Fewer low handicaps and more higher handicaps. But the predominant winners are still in the 16 range for men, for women. This has not changed..00% Distribution of Handicaps of inners.00%.00%.00%.00% 0.00% hat handicaps are placing in competitions? The pattern is similar the winners:.00% Distribution of Handicaps of Prizewinners.00%.00%.00%.00% The Australian Golf Handicap System Page 6

7 hat scores are required win or place in competitions? All scores in this report are adjusted for the course rating, and converted stableford equivalent. As with handicaps, there has been a shift higher scores. For men, 41 is the predominant score compared 37 and 39 under the system. For omen, 37 is still predominant under both systems, but there is still a clear shift higher handicapped winners. 12.0%.0% inning Scores 8.0% 6.0% 4.0% 2.0% Do these patterns vary depending on field size? Indeed they do. Under the system the most frequent winning score for fields 6 thru was 37 points. As the field size increased this rose 39, 41, 41 and 43. Follow the 43 score through different field sizes, its rising share of the winning scores is clear..0% inning Scores for Various s System.0%.0%.0%.0% s Scores The Australian Golf Handicap System Page 7

8 For women, the pattern is similar. inning Scores System.0%.0%.0%.0%.0% Scores However it should be noted that what we are seeing here is merely the impact of a larger field on the standard deviation effect. ith more players in the field, there are more chances for one of them play an upper extreme of their performance distribution. The system evidences the same rise in winning scores as field size increases. How has handicap distribution changed from the system the system? There has been a distinct move higher handicaps with the system..0% Distribution of Handicaps.0%.0%.0%.0% Has there been any settling down in the period since 9 April? No, there is no significant variation between the month on month distribution of handicaps in the months following the introduction of the The Australian Golf Handicap System Page 8

9 system. The handicaps issued on Day One of the system reflected the same distribution of handicaps as in evidence seven months later..0% Distribution of Handicaps ( System) by onth.0%.0%.0%.0% hat are the implications for an Equitable system? Neither the nor the systems are representative of a level playing field. Under the, the high markers were disadvantaged so that they won far fewer competitions than their representation in the field. any of them were chronically playing at handicap levels far in excess of their playing handicaps. Essentially this was due the uneven way that increments were applied. Handicaps for high markers only eased out by 0.1 stroke for a poor round, no matter how poor, but they were tightened far more quickly if the player had the occasional good round. Under the system players are being handicapped closer their recent form, but what with the greater inconsistency of the higher markers, when field sizes grow, there are enough chances for a high marker put in one of his or her exceptional rounds, and the high markers are now winning more than their fair share of the competitions with larger field sizes. It is clear that a reduction in BFE, or in the number of best scores taken, would tilt the playing field in favour of the lower markers. However there is likely be some negative impact on other handicap groups. odelling of specific solutions should be performed before introducing any change. ichael aher BSc (Syd) BA (Harv) Sydney th arch 11. The Australian Golf Handicap System Page 9

10 Appendix 1 About the Author GA commissioned a statistician with significant experience in developing practical solutions conduct the data analysis. ichael aher also has longterm peaklevel management and board experience with major Australian and international companies. ichael comes in this with a fresh outlook and without any industry baggage. ichael plays regular club competition golf in Sydney. His current professional focus is FX trading using aumated algorithms. The Australian Golf Handicap System Page