To me the new average scoring system resembles (or may actually be) the standard USGA handicap system...which for those of you who don't know is the following formula...
(Your Score - Course Rating) X 113 / Slope Rating = Score Differential
Example:
Score = 85
Course Rating = 72
Slope Rating = 123
The actual calculation would now look like this:
(85 – 72) X 113 / 123 = 11.94
You need a minimum of 5 and a max of 20 rounds to have a legit handicap...in this case WGT has chosen a fixed number (some say 10, others 14..personally i think its closer to 20 as 1 round out of 10 would move your "average" more than 1 round out of 20...which seems to be the case).
Every course has a Slope Rating, and a Course Rating.
USGA Course Rating is an evaluation of the difficulty of a golf course for scratch golfers. Actually, the number is an estimate of the average scores of the best 50-percent of rounds played by scratch golfers at the course being rated. Course rating is very easy to understand because it is expressed in strokes. A par-72 course that is easy might have a course rating of 68.9; one that is difficult might have a course rating of 74.5.
USGA Slope Rating is a number ranging from 55 to 155 that represents the difficulty of a course for bogey golfers relative to the USGA Course Rating (which represents the difficulty for scratch golfers). Slope rating is not expressed in strokes, but, rather, is a ratio. The higher the slope, the more difficult the course plays for bogey golfers. A slope rating of 113 is considered average.
The following table explains how many rounds are used in computing a hadicap..
(this is where i beleive WGT is using a different formula, and perhaps taking the calculations from all 20 rounds, not the ten, so its your 20 best rounds i think).
Rounds................Rounds To Use
5-6.......................1 Lowest
7-8.......................2 Lowest
9-10.....................3 Lowest
11-12...................4 Lowest
13-14...................5 Lowest
15-16...................6 Lowest
17........................7 Lowest
18........................8 Lowest
19........................9 Lowest
20......................10 Lowest
The last step will produce your golf handicap. For example we will use the number of rounds played as the maximum of 20. With 20 rounds played you will use your 10 best scores. First you will total your 10 best score differentials created in step 1. Total the 10 best differentials and then divide by the number of rounds, 10. The last part of the calculation is to take the last calculation and multiply this number by .96 (96%) and keep 2 decimals with no rounding. This is your Hadicap index. Now if you reverse this number (subtract it from 72), i believe it will be pretty close to your average.
The handicap system goes much further when playing different course, as not all courses are rated the same, so you would take your hadicap index, insert it into a different formula, and get your "course hadicap" for each individual course you play...you are not the same hadicap at all courses because some are harder than others, i.e. you may be an 8 at one course, and a 7 or a 9 at others. WGT does not go this far with the averaging system because your average would change from Kia, to BPB, to STA, which it does not.
Also they do not use "equitable stroke control" which is system that only let's you take a certain number of strokes (or a maximum number of strokes) on any given hole based on your course handicap...meaning you cannot take a 10 on a hole if you are a 7 handicap, i think the worst you can card is a double bogey.
So if someone wants to do the math out on their most recent10, 15, and 20 best rounds to see how it computes i would be interested to know, however not interested enough to do it for myself. The problem being there are 4 different courses to take slopes and ratings from, where WGT is using only one rating, and one slope for their formula...you would probably have to average the slopes and ratings of all 4 courses to get the two numbers you need for the formula.
EDIT** I think one thing i failed to mention in all of this is that which ever scores they are using to calculate your average, it is based off the most recent ones...so lets say they use the 20 best out of your 30 most recent scores...as soon as you shoot score #31, score #1drops out...now that may or may not affect your average if score #1 was not one of your 20 best, and vice versa. Also if say score #31 is a -3 (3 under par) and it kicks out score # 1 of even (even par), and score # 1 was being counted as one of your best 20 scores, then your average will drop...it all depends on what order your scores are shot in...if you have a decent streak of rounds, say five in a row, when it comes time for those five scores to be replaced, and they are replaced with better scores, you can expect your average to drop a bit faster, as five out of the top 20 are being replaced with better scores. Of course one can still sandbag, but it becomes more difficult, as you have to now shoot many more (10 +) bad rounds in a row, or close together, to affect your handicap...Now in real life this is not possible anywhere there is a handicap committee who checks cards, as you cannot play 10 rounds a day like you can here...but it is still IMO much easier to see if someone is attempting to raise their handicap because they must now shoot many consecutive bad rounds... EDIT**