Archives for the ‘Statistics’ Category

The numbers behind Great Shot Points (GSPs)

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Shotties.  Greaties.  Whatever you call them, they are your reward for sticking one close, and they are the tiebreaker in those live contests.  You probably have a rough idea how they are calculated, but we’re going to break it down into nauseating detail for you.

Hole-outs are easiest to understand.  Any hole out of 25 yards or more gets shotties.  Your distance in terms of yards times 100 is your reward in GSPs.

Let’s talk about putts.  Putts over 25 yards do NOT gain you GSPs.  However, all made putts that result in a double eagle DO gain you GSPs.  Convert your putt distance to yards and multiply by 100 — you won’t get much, but driving the green on a par 5 and putting in for albatross is definitely point-worthy.

Now, without holing out, the ball has to travel roughly 80 yards from the lie where you hit to get shotties, and the ball has to be within 6 feet.  You’ve noticed that any time you are on the green and the screen says 5 feet away (and you were 80 yards out), you get points.  But if the screen reads 6 feet away, you get nothing.

Let’s complicate things some more.  You could actually be 79 yards from the hole, and if the ball stops up to 3-5+ feet past the hole, you’d get shotties for the ball traveling 80 yards. Conversely, you could be 81 yards from the hole and have the ball stop 3-5+ feet short of the hole, and you wouldn’t get shotties because the ball’s total distance from where you hit was less than 80 yards.

So for non-holeouts, how can you figure your points?  We’ve got a couple ways to figure that:

1) Want a formula?  Here’s how you can calculate the points you’ve earned:
GSPs = ShotDistanceToPin*(100-(1+1/60)*InchesFromPin)

2) Want a grid?  Open this sheet and find your yardage across the top, distance from the hole down the side, and expected GSPs in that cell.

Special thanks to Skipper Horner and others in the GT Community for their input on this one!



Your Golden Tee Handicap, Decoded

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For years, I hadn’t been entirely sure how Golden Tee calculates a player’s handicap that is shown in the upper right when starting a new game, and also in relation to your handicap score shown after each hole played.  Most theories pointed to some formula calculated by the average of your best 10 of your last 20 games, but I could never get that concept to work exactly right.  As it turns out, the only factors that play into your handicap adjustment after a game are your handicap entering the game, and the score you just recorded.

First of all, there are two places where you can see your handicap to two decimal places, and they are both on the website.  The first is in the “My Stats” tab under the “Totals” filter:

handicap1

 

The next is in the “Stats Play” or LIVE Play” tab, if you expand the contest results by clicking ‘More’ in the “Details” column.  The handicap shown here is your new handicap as calculated after this round was played:

handicap2

If you are brand new, you need to play 36 holes to establish a handicap.  This will be the additive inverse of the average of your two scores.  So if you shoot a -4 and a -6, your handicap will be a +5.  Almost.

There’s a twist, because in that scenario, your handicap would actually be 5.04.  Why?  It’s because IT actually calculates your handicap per hole, not per round, and then represents your 18-hole handicap by multiplying 18 by your per-hole handicap.

So my average is -5 after two games.  To get my per-hole average, I need to first divide by 18.  5/18 = 0.27777.  IT does not retain decimal places past the hundredth, so this rounds to 0.28.  Therefore, my per-hole handicap is now 0.28.  To translate this back to an 18-hole handicap which is what you normally see, take the 0.28 * 18 to get 5.04.

You may have noticed that your handicap seems to move up or down in increments of 0.18, and it’s because of the rounding to the nearest hundredth for your per-hole handicap.  If I had 0.29 per hole, for instance, my handicap would be the next-highest possible value of 5.22.

So that establishes your handicap and also helps explain why your handicap goes up or down by factors of 0.18.  But how do you know if it’s going to change after your round, or how much?

There’s a grid for that — check it out:

Final Score * -1 minus Entering HCP
Stroke difference from Entering HCP
MIN MIDPT MAX HCP Change
6.5 7 7.49 1.26
5.5 6 6.49 1.08
4.5 5 5.49 0.9
3.5 4 4.49 0.72
2.5 3 3.49 0.54
1.5 2 2.49 0.36
0.5 1 1.49 0.18
-4.99 0.49 0
-14.99 -10 -5 -0.18
-24.99 -20 -15 -0.36

In simplest terms, if you shoot 1 stroke better than your handicap, it goes up 0.18.  If you shoot 2 strokes better, it goes up 0.36, and so on.  But it takes a really bad game to move it down.  You have to shoot at least 5 strokes worse than your handicap to go down just 0.18, and 15 strokes worse to move it down another factor.  And, it’s capped there…your handicap can never go down more than 0.36 after any single round.  However, there doesn’t seem to be a limit on how much it can improve after a single round.

For those of you looking for a formula, take the midpoint divided by 5.55555 to get the expected handicap adjustment moving up, and the midpoint divided by 55.55555 to get it moving down.  So now you can see how a really good game can cause your handicap to jump up quite a bit, while a really bad game doesn’t hurt you too much.  It’s weighted to deter sandbagging.

So, the entire range in the row comes into play.  To improve my handicap by at least the minimum 0.18, I need to shoot at least 0.5 strokes better than my handicap entering that game.  And if I end up shooting 1.49 strokes better, it still goes up by 0.18.  I’d need to hit the next plateau of 1.5 strokes better to see it go up 0.36 after the game instead.

What about 9-hole games?  To answer that question, I looked more specifically at what happens if you DNF a game.  Many times your HCP does not change after a DNF, but I also saw it go both down and, unexpectedly, up after a DNF as well.

So how does that happen?  IT basically applies your per-hole handicap to the unplayed holes to fill out a full game of 18.  So if I played 5 holes and quit, it would add my score after 5 holes to my projected score over the next 13 holes, based on my current handicap.  IT uses that as my final score and adjusts the handicap according to the grid.

Here are two examples of how I saw that work.  Entering one game, I had a 24.66, so that’s -1.37 per hole.  I shot an 8 on the first hole (+4), and then quit on hole 2.  So, take the -1.37 * 17, which equals -23.29.  Now add in the +4, and I’m -19.29 to complete the round.  That’s more than 5 full strokes worse than my entering handicap, so it goes down by 0.18, and that’s what happened.

Now I’m at a 24.48, which is -1.36 per hole. So I’m at -23.12 for 17 holes. Now I shoot an eagle on the first hole for -2, and quit on hole 2 again.  Add in my -2 on the first hole, and I’m -25.12. The grid says that’s good enough for my handicap to jump by 0.18 since it’s more than 0.5 strokes better than my entering handicap, and that’s what happened.

So, for a 9-hole contest, it should work the same way.  You don’t divide everything in the grid by 2 — you just fill in the 9 remaining holes with your per-hole handicap and add it to your score.  So if I’m back at a 24.66 handicap, -1.37 per hole, then that’s a score of -12.33 for 9 holes.  In order to see my handicap improve, my 18-game total has to be at least 0.5 strokes better than my entering handicap, so I’d need to shoot a -13 on the 9-hole contest for a total of -25.33.  If I only shot a -12, my handicap would stay the same per the grid.  I’d have to shoot a -7 for a total of -19.33 to see it actually go down by 0.18, since I’d then be at least 5 full strokes worse than my entering HCP.

So now you know what to expect regarding your handicap after each game, and hopefully that puts to rest the questions you may have had about how it adjusts.



Golden Tee 2011 — A Statistical View

By • Category: 2010 - Golden Tee LIVE 2011, Features, Statistics • • Leave a Comment (2)

Now that you’ve hopefully got many games of 2011 under your belts, you have a pretty good idea of the holes on which you score well, but more so, you probably know which holes are giving you fits.  Ever wonder if other players like you are struggling on the same holes?

Better yet, wouldn’t it be nice to know for sure if laying up for birdie on a tough par 4 will net you a better overall score than if you alternate between the tough eagle and the disastrous par or worse?  If an average player knew that a good player only eagles certain holes a small % of the time, he could decide to play the odds and take the safe birdie.

Well, a short while back I was approached by Jeremy Olson, a statistical analyst from Chicago who plays under the name NIGHTRAIN !.  He had developed a model to handicap each hole on the course based on certain variables and the scores he was shooting on them, but he needed a larger data set.  With the help of the GTF community, we’ve gotten many volunteers to give us access to their hole-by-hole scores on the 2011 courses, and with this data, Jeremy has been able to develop some awesome-looking spreadsheets and dashboards with great statistics for each hole!

SO, let’s take a look at some data!  These statistics are from 7-8 players whose handicap ranges from 15 to 21, which turned out the be the ideal audience for this type of analysis.  Also, the first few rounds played on these courses and any obvious outliers (blow-up rounds at 2AM, for example) were excluded.

First, pop open this spreadsheet and browse over the first tab.  Each course has all its holes classified into one of 5 categories, as defined below (remember that GT Par is the best score you can normally shoot without holing out — we used a slight modification of GT Par and called it “Potential”):

Easy:  75% handicap or better.  Only unforced errors can lead to dropped strokes.
Moderate:  50-75%.  Player is NOT faced with a decision whether or not to lay up.  Probability of GT par is reduced because of course variables, but chance of a penalty stroke is minimal.
Risk/Reward:  40-55%.  Player IS faced with a decision whether or not to go for GT par. Average score should be within +/- 0.10 of birdie (meaning the risk of getting Eagle is in balance with the penalty of par).
Professional:  40% or less. GT par is very difficult.  Risk of bogey outweighs benefit of Eagle.
Difficult:  50% or less.  No option to lay up with significant danger.  Probability of GT par is negative.  Chance of bogey high.

The % column shows how often players score the potential value (normally GT Par) on these holes, and the Avg. Score column shows that value for these holes.  You may find that “Potential”  is flexed a little bit towards what average/good players can realistically be expected to shoot on particular holes.

Now, click the Scorecards tab.  Here you see the hole-by-hole breakdowns for each course.  You’ll see an additional column for Handicap — the holes have been handicapped based off players’ percentage of realized Potential on those holes (again, you can also think about this as the ranking of a player’s average score on this hole relative to GT Par).  We didn’t always want to use GT Par as the standard for handicap because there are certain holes like Alpine #7 that may have a low GT Par %, but they are not necessarily difficult to birdie.  Now you truly know which holes are causing players in the 15 to 21 handicap range the most trouble!  You can use this knowledge to help with course management, and you can also use these ratings when playing with your buddies to know where to give strokes if you want to even things up based on your handicaps!

That’s the overview, but it gets bigger and better — each hole is analyzed in further detail in the write-up for each course!  Alpine and Grizzly are done and will be published soon, so be ready to head on over to those sections to see even more detail.  I’ll also soon be rolling these stats into a new format for each hole’s write-up!

Finally, we’ll be updating these statistics at various times throughout the year to keep them up to date, so hopefully this data can help your scores improve!  We’ll normally be pulling the 100 most recent games to get a good representation of how all our volunteers are currently performing.  Thanks big time to Jeremy for putting in the effort to gather up this valuable data for us!



A new wave of statistics

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I hooked up with a stats analyst to take a better look at Golden Tee 2011, and I’m looking for volunteers to help donate their statistics towards our cause!  Check out this example. If you want to help classify all these holes, send me a note with your handicap and your goldentee.com login and password — then we can pull your stats from the site and help grow this database for analysis!  Contact me with any questions — thanks!



How Great Shot Points are calculated

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Ever wonder how GSPs are calculated? All I used to know is that if I hole out from 300 yards, I get 30,0xx GSPs, but where does the xx come in? Fractions of a yard? Possibly I guess.

More importantly, I wondered how they were calculated when you land within 5 feet, let’s say from 300 yards? Probably something to do with starting at 30,000 points and then deducting based on distance from the pin…

Well, our buddy Skipper put together an entire grid so that you can look up how many GSPs you’ll get in any given situation!  Click here to open the spreadsheet and take a look at the grid.

And here’s another note — it measures how far the ball traveled from point A to point B.  So if you backspin the ball in the cup, you’ll get a few more GSPs than if you rolled it in (due to the width of the cup).  Also, and probably more importantly, if you backspin the ball to within 5 feet, you’ll get a handful more GSPs than if you rolled it up to within 5 feet, because that’s 10 more feet of total travel distance.

Just another fun fact that you can use to impress your friends!



Player rating and handicap

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Most of this information was borrowed from a thread on the ITS games forum — thanks to SkipperRipper, Dannyboy, bigdog423452, Thor, and the other guys on the forum for the information!

Your player rating is actually your number on the ELO rating system, a system used to rate players in two-player games like chess. It doesn’t come into play unless you’re playing in a handicap tournament, but you can compare it to other players to see where you rate — the higher, the better. If you beat players in a contest whose rating is higher than yours, your rating goes up, and vice versa. DNFs really knock your rating down, from what I understand. Most of the top players rate over 3000, with the best even topping 3300.

You earn a handicap after playing 36 holes. There is a formula for figuring that too, but it’s usually about 3.5 to 4 strokes higher than your average. So, if you average about -15, your handicap will be +19. Your handicap is always updated based on your last 25 games played.



Statistics

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The following statistics are tracked for each player during a live round of Golden Tee, and the leaderboard will show what player had the best/most of something on that specific machine.

Longest Drive
Longest Putt
Most Birdies
Most Eagles or Better
Driving Accuracy
Greens in Regulation

Great Shot Points
Great Shot Points are awarded for just that. If you’re 80 yards or more out and land a shot within 5 feet of the hole, you get a certain number of GSPs. You also get a big amount of GSPs by holing out from anywhere outside 25 yards. Great Shot Points are one of the statistics kept by the game for each player to have played a specific course on that specific machine. If you accumulate the most GSPs for a particular course, you’ll see your name on the leader board!

Golden Tee Points
Golden Tee Points are also accumulated for each player on each course as you’re playing a live event. The breakdown of GTPs is as follows:

Triple Eagle – 2500
Double Eagle – 1500
Hole in One – 1000
Eagle – 250
Birdie – 100
Sand Save – 75
Par – 50
Green Hit – 50
Great Shot Points – 1 point for every 100 Great Shot Points
Driving Distance – 1 point for every 10 yards for drives (in the fairway only)
Putting Distance – 1 point for every foot for made putts