My Flagstick In vs. Out Data

[iacas]

I spent the better part of two days conducting this test last summer. I tested a few situations:

In chart form:

And for those who like the visuals…

• I used a PerfectPutter and positioned it far enough away that the ball wasn't bouncing at all but close enough that the ball wouldn't deviate too far from the intended line.¹
• I used Snell MTB Black balls.
• The flagsticks were standard Par-Aide fiberglass flagsticks. It wasn't windy, but there was often a little breeze.²
• I tested on the flattest section of the greens I could find. The actual holes were as level as could be. Rolling the ball from close distance minimizes this anyway.
• I rolled balls from all around the hole so as not to overly damage one portion of the hole. Also, little "tracks" can form even after a few putts, so I wanted to balance that out as much as possible.
• The flagsticks were relatively centered in the hole, with only a little "wiggle room."
• I did not measure how far away the balls that didn't go in ended up; I considered it pretty obvious that a ball that hits the flagstick is going to finish closer to the hole than one that doesn't. This was clearly the case.
• I alternated five ball rolls with the flagstick in, five without. Then five without, and back to five with it in again.
• On putts where results seemed highly variable, I rolled more putts - up to 100. On putts that were a given (like 3' by speed at the center of the hole), I rolled fewer putts; as few as 10.
• I conducted the test on different holes and from different angles. I simply moved on when I felt I'd rolled enough balls at the holes that I could start to see a change to the lips, like some of the balls were "denting" or "rounding" the lips a little. I used holes where the lips appeared to be somewhat uniform (though obviously the specific soil density can vary around even a uniform looking hole).
• Stimp speeds were 9.75 to 9.9 feet.
• Distances off-center were done with a centered laser calibrated to aim straight (angular error in the laser was oriented upward) with a ruler across the hole, confirming both the proper hole dimensions and the distance off-center.
• I tried to roll balls from the same spot(s) on the PerfectPutter, but obviously there was some little error there - a few millimeters.
• I never rolled more than five balls at a time - and no balls ever hit a ball or balls in the hole and bounced out because of that. If balls did pile up on one side or in the front or back of the hole, I'd remove them. This rarely happened, though, as the holes are deep enough and only four balls would be in the hole when the fifth ball was rolled anyway.
• I'll add more information if I remember anything relevant.

¹ Even with the PerfectPutter, you often can't make more than half of the 20-25 foot putts you roll across a real green. Just the tiniest deviation, hitting a bump slightly differently, can magnify over the duration of the putt and miss high or low even though you're trying to release the ball from the same exact spot on the PP.

² One of the putts that almost surely would have gone in (as 98 others did) I felt was knocked away by the wind moving the flagstick at just the right time.

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Conclusions

Leaving the flagstick in helps quite a bit, particularly on shots that are at the edges of capture speed/effective hole size. For example, at 4' by speed and 3/4" off-center, that's just beyond the capture size (only 8/100 went in) without the flagstick, but the flagstick took enough speed off that a 44/100 putts dropped with the flagstick in.

At 3' by speed, the capture width of the hole is about 0.8 to 0.85" wide: wide enough for all of the 3/4" putts to go in, but few of the 1" putts. With the flagstick in, the 3/4" putts still went in, but the 1" putts that just nicked the flagstick scrubbed enough speed from the ball that a few more (14/50) putts went in.

The largest percentage gain was the 6' speed at 1/2" off-center. At this distance from the center, only one putt went in (I would swear that I rolled it like all the others, but sometimes a putt that would have popped up and out hit some part of the hole just right and popped up and fell in), but since the contact with the flagstick (look at the image above) was still pretty flush, a lot of speed was taken from the ball and 45/100 fell. This is still fewer than half, but because the 1/100 is so low, the percentage is the largest. Similar inferences can likely be made on the 5' by putts - at 1/2" it's awfully close to the edge of the capture width of the hole, and at 3/4" is pretty much beyond it (again, though, a pesky 1/100 putts went in). These low make percentages without the flagstick make it possible for the delta between the flagstick in vs. out to be in the upper 30s to lower 40s.

[Vinsk]

Nice Erik. Did you email this to your friend who had asked you your thoughts on putting with the flag stick in? I think this is pretty well done and presented experiment.

[p1n9183]

Nice test @iacas. It definitevely shows us that leaving it in help us.
Don´t get me wrong but I still think it is incomplete. It will be complete when we know how much strokes saves us over a round or season in average. As i said in another post, in january over 6 rounds I never hit a putt with that conditions, so living it in didn´t help me at all (just visually). Obviously 6 * 18 = 108 greens played is such a small sample to make conclutions. There is data that show us how many putts a scratch or a 10 handicapper hit the flag with a speed over 3 feet each round?

 

[iacas]

4 minutes ago, p1n9183 said:

Don´t get me wrong but I still think it is incomplete. It will be complete when we know how much strokes saves us over a round or season in average.

I disagree. Not only are different people going to see different rates (my kid plays 3x as much golf as I do, maybe more, so it's going to save her more than it saves me, and that's if we're equally skilled putters).

This - as well as all of the other studies showing the same thing - show that leaving the flagstick in is an advantage, which the USGA/R&A said it was not when they both proposed and issued the Rules change.

[gbogey]

Not surprised by the speed results but the off center putts results are surprising, at least to me.  Didn't realize there would be that much of a benefit there.

[iacas]

18 minutes ago, gbogey said:

Not surprised by the speed results but the off center putts results are surprising, at least to me.  Didn't realize there would be that much of a benefit there.

I believe that some of that benefit is due to the ball being near the capture speed of the hole, and the flagstick scrubbing just enough speed from the ball.

Plus, a lot of the tests included the (IMO somewhat ridiculous) putts that roll nine feet past the hole. Those are going to heavily favor center strikes, as off-center strikes are still going to miss with that much speed.

Plus, 1/2" off the center of the hole is not that far off-center.

[ChetlovesMer]

1 hour ago, iacas said:

This - as well as all of the other studies showing the same thing - show that leaving the flagstick in is an advantage, which the USGA/R&A said it was not when they both proposed and issued the Rules change.

Is it a possibility that they all know its an advantage, but they are claiming its not? My thought is they know one of the biggest complaints from golfers is slow play. So, they are trying to find ways to speed up the game. Then perhaps they are claiming no advantage because they don't want to anger the older guys? … I don't know, it seems obvious to me that it has to be an advantage. But they are still sticking to the "no advantage" line. Which to me seems weird. I mean these aren't dumb people, right? 

[iacas]

4 minutes ago, ChetlovesMer said:

Is it a possibility that they all know its an advantage, but they are claiming its not?

They didn't test. They assumed.

4 minutes ago, ChetlovesMer said:

My thought is they know one of the biggest complaints from golfers is slow play.

Maybe, but this is a ridiculous way to do it. At most it's going to save a few seconds, and that's only if everyone just leaves it in the whole time, for every putt. And at worst it delays or slows play more.

[phillyk]

8 minutes ago, ChetlovesMer said:

Is it a possibility that they all know its an advantage, but they are claiming its not?  I mean these aren't dumb people, right? 

I don't get it.  They can't be that unknowing. But if they did know it was an advantage, why not admit to it and tell everyone to use the stick so as to speed up play? Maybe weighing the opinions on the skill of putting versus pace of play? So stay quiet and play ignorance? Who knows, but I feel something has to be off internally about how they made this call.

I like the delta chart.  

11 hours ago, iacas said:

(again, though, a pesky 1/100 putts went in).

With both pin in and out, how many putts went in that you thought shouldn't have (other than maybe the 2 1/100s)? With pin in, how many if any, putts hit pin and popped out that probably would have gone in had the pin been out (or was it just the one you mentioned above with the wind)?  The latter question is one I feel a lot of people are worried about happening.

[iacas]

2 minutes ago, phillyk said:

With both pin in and out, how many putts went in that you thought shouldn't have (other than maybe the 2 1/100s)?

I have no idea, and the thought never occurred to me except in those incredibly rare cases. For example on the 33/100, I could see after rolling a ball or two that some percentage would go in, even though the first two missed… they didn't miss by much.

2 minutes ago, phillyk said:

With pin in, how many if any, putts hit pin and popped out that probably would have gone in had the pin been out (or was it just the one you mentioned above with the wind)?

Like I've said, it's in the very low single digits per 100 range - nowhere near enough to offset the gains.

[Lihu]

The data makes sense. People will tend to hit more aggressively, and I can only imagine that hitting short will be a little less common?

[iacas]

10 minutes ago, Lihu said:

The data makes sense. People will tend to hit more aggressively, and I can only imagine that hitting short will be a little less common?

I don't know. Not really something the study was designed to test, as you know. 😄

[iacas]

Flagstick in not such a sure thing, new Golf Digest study from Cal Poly professor shows - Golf Digest

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This data I can believe and it is along the lines of the data from Edoardo Molinari's testing.

Basically, putts that graze the flagstick but are still going at a speed at which they might be holed can be kicked out of the hole occasionally. Which makes sense, really - at speeds where the ball would go in the hole every time, the flagstick can only match at best and hurt at worst if the bar is set at "100%."

I did not test "breaking" putts on the idea that for a short enough distance - i.e. when the putt is entering the hole - it's not "breaking" at all - it's traveling in a pretty straight line. Yes, a 2% slope at the hole lowers the bottom lip of the hole slightly, but only 0.085 inches, and that's from top to bottom, not edge of the flagstick to the bottom of the cup.

At the end of the day, though, I believe this zone of putts would be pretty small. They have to be just the right speed (still capable of going in), and just the right amount off-center. I've never said the flagstick always helps, only that over a normal distribution of putts (various speeds, various entry points), it's going to provide an overall advantage.

This is likely one of the times when it can hurt.

It'll be interesting to see the full data when they publish (assuming they do - they rolled nine putts in the one example they gave), and interesting to see if they roll putts at speeds where the balls wouldn't go in without the flagstick. Otherwise I fear people are going to misread the study as proof the flagstick hurts overall.

Unless of course it shows that overall, it hurts. But I'd doubt that. (And I'm not counting the stupid 9' by distances from studies like the MyGolfSpy tests or Dave Pelz's earlier chipping study.)

I'll go where the data says we should go.

P.S. Watch the video and notice two things… One, if the flagstick is centered or if it's leaning, and two, watch the entry points even from 32" away - some of them are different than others. The putts rolled from even 32" away can hit different bumps and change directions a small amount a hundred times between the roller and the hole.

[saevel25]

Could they do this test on an artificial surface to take out the variance of green irregularities?

[Wally Fairway]

Erik -
Thanks for the data and the study, I haven't been able to put any of this into practice yet (thanks winter!)
But the data certainly shows keeping the pin in is going to be a huge advantage, by huge I mean maybe up to a couple of strokes a round.
Your comment about breaking putts intrigues me even more, as I can see players taking a slightly more aggressive approach to breakers if they leave the pin in. It will be interesting, at least to me, to see how this affects a course like ANGC, and some of the pin placements with severe breaks, as not only will it allow more putts to go in, but it will stop some putts that might have gone 4' or more past the hole and make the next putt a tap-in vs. a much more challenging attempt.

I can see this changing the target speed for the first putt, to expand an 'acceptable' miss to include distances further from the hole because a) they have a better chance of going in if they hit the pin and go in, b) they have a better chance of being close if they hit the pin and stop close to the hole and c) the come back putt should be easier to make from say 3-4 feet because you can leave the pin in for that as well.
I can imagine the data will show not only statistically significantly more 1-putts, but also a significantly fewer 3-putts. Time, and data, will tell - do you have a feel or gut instinct on this as well.
 

[iacas]

29 minutes ago, saevel25 said:

Could they do this test on an artificial surface to take out the variance of green irregularities?

That would not do that. Our artificial surface has variances. Unless it was a perfectly smooth surface, it's going to have irregularities, and the balls will take different paths. I tested from 18" to minimize these, but they still existed, I'm sure.

And an artificial surface probably wouldn't have the consistency (when the ball hits the far lip) of dirt and grass.

Just now, Wally Fairway said:

Thanks for the data and the study, I haven't been able to put any of this into practice yet (thanks winter!)
But the data certainly shows keeping the pin in is going to be a huge advantage, by huge I mean maybe up to a couple of strokes a round.

Highly unlikely it's going to be a couple strokes a round on average. There are going to be people who smash the stick a few times and gain even four or five shots a round (particularly if they're poor putters from, say, six feet), and there are going to be people who go months without the flagstick helping them. See my last note for more.

Just now, Wally Fairway said:

Your comment about breaking putts intrigues me even more, as I can see players taking a slightly more aggressive approach to breakers if they leave the pin in.

If you want to putt with the flagstick in from short range, there are times it can help:

• the more aggressive line
• when the flagstick helps you aim
• when the shadow of the flagstick helps you aim

That's about it, and if you take the more aggressive line, it looks like you don't really want to miss low, because there's a sliver of speed/off-centered-ness where the flagstick can hurt you.

I also don't recommend taking the more aggressive line. Make the hole bigger. Play a bit more break and make the hole bigger.

I've only recommended leaving the flagstick in from 25+ feet or so.

Just now, Wally Fairway said:

ANGC, and some of the pin placements with severe breaks, as not only will it allow more putts to go in, but it will stop some putts that might have gone 4' or more past the hole and make the next putt a tap-in vs. a much more challenging attempt.

Few holes are cut on areas of severe break at ANGC… it's just that the turf between the ball and the hole is sloped quite a bit. It'd be pretty nuts to put a pin at Augusta National on a 4% slope. Though we probably see a few 3% holes on occasion, like on #9.

Remember, too, every putt is going straight when it hits the lip of the hole. It can't and doesn't break "in the air." And the lip is not significantly lower just because the hole is cut on a slope.

Just now, Wally Fairway said:

I can see this changing the target speed for the first putt, to expand an 'acceptable' miss to include distances further from the hole because a) they have a better chance of going in if they hit the pin and go in, b) they have a better chance of being close if they hit the pin and stop close to the hole and c) the come back putt should be easier to make from say 3-4 feet because you can leave the pin in for that as well.

I don't think that it should do that, because the vast majority of the time your ball does not pass within the middle 2.18" of the hole where it could touch the flagstick.

Just now, Wally Fairway said:

I can imagine the data will show not only statistically significantly more 1-putts, but also a significantly fewer 3-putts. Time, and data, will tell - do you have a feel or gut instinct on this as well.

So here's the crux of anything, as it's easy to lose sight of the forest for the trees when you get into this:

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At the end of the day:

• ~94% of the putts hit from 25’+ won’t hit the hole at all (5.6% were made in 2018 from 25+ feet on the PGA Tour).
• Of the ~6% of the putts that hit the hole, a good number of them will either:
  • Not hit the flagstick (they'll hit outside the middle 2.18") or
  • Will be going at a slow enough speed that the flagstick won't change the fate at all.
• Of those that remain:
  • The majority will be helped by the flagstick.
  • A minority will be harmed by the flagstick.

We're focused right now in golf on the last little bit, but we're talking about maybe 1% of putts… from outside of 25', which is already probably less than 1/3 of the putts we take. So, 1% of 10 putts per round?

[Swooshgolf]

On 1/29/2019 at 8:37 AM, iacas said:

I disagree. Not only are different people going to see different rates (my kid plays 3x as much golf as I do, maybe more, so it's going to save her more than it saves me, and that's if we're equally skilled putters).

This - as well as all of the other studies showing the same thing - show that leaving the flagstick in is an advantage, which the USGA/R&A said it was not when they both proposed and issued the Rules change.

I can only imagine that the USGA/R&A  did thorough testing to get their conclusion.

[klineka]

20 minutes ago, Swooshgolf said:

I can only imagine that the USGA/R&A  did thorough testing to get their conclusion.

Why? What reason do you have to think that?