How did the treatment of 9-hole scores change under the WHS™ in 2024?
Prior to January 2024, one 9-hole score must be combined with another to create an 18-hole Score Differential™ before it could be counted for handicap purposes.
Now, when a player posts a 9-hole score, the WHS will automatically calculate an 18-hole Score Differential for the round, based on the player’s 9-hole Score Differential and expected Score Differential based on their current Handicap Index®, allowing the 9-hole round to be considered in the player’s Handicap Index calculation right away.
As part of this change, golfers are required to play all 9 holes with a valid 9-hole Course Rating™ and Slope Rating™ instead of the previous minimum of 7 holes.
What are the benefits of this change?
The growing number of golfers who regularly play 9-hole rounds no longer have to wait for another 9-hole score for their Handicap Index to be updated.
In addition, it 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.
Finally, this new method produces a more consistent and comparable Handicap Index for golfers who post 9-hole scores. For example, under the previous method:
Combining two independent 9-hole scores often resulted in more volatility and was highly dependent on the order in which scores are combined.
It was also common for two good 9-hole scores to be combined that produce an 18-hole Score Differential that is better than any of the player’s 18-hole scores made over 18 consecutive holes. The impact was an artificially low Handicap Index.
How is a golfer’s expected score determined to create an 18-hole Score Differential?
Once the player’s 9-hole Score Differential has been calculated, it is combined with an expected Score Differential based on the player’s current Handicap Index to create an 18-hole Score Differential.
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.
An expected score can be thought of as a neutral value, meaning that a good 9-hole round (relative to the player’s ability) will result in a good 18-hole Score Differential. An average 9-hole round will result in an average 18-hole Score Differential, etc.
Here is an example of how a 9-hole score is converted into an 18-hole Score Differential:
A player with a Handicap Index of 14.0 posts a 9-hole score of 41. Based on Course Rating™ and Slope Rating™ of the tees played, this results in a 9-hole Score Differential of 7.2. That value is then added to the player's expected 9-hole Score Differential to determine an 18-hole Score Differential of 15.7, which will be entered into the player's scoring record immediately.
When establishing a Handicap Index, how are 9-hole scores treated?
To establish a Handicap Index, a player must play and post a total of 54 holes, which can be made up of 9- and/or 18-hole scores. The use of expected score does not come into play until a golfer plays and posts 54 individual hole scores.
Once the player has posted scores from a total of 54 holes and an expected score can be determined for the player, an 18-hole Score Differential will be calculated for each 9-hole score and displayed within their scoring record. At this time the player will have established their initial Handicap Index.
How has the score-posting procedure changed for a 9-hole score?
The procedure for posting a 9-hole score has not changed, and the options for posting scores continue to be through an app (for example, the GHIN app), an Allied Golf Association’s website, or kiosk at the golf course.
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