Dave Pelz published an article in which he says this:

The test results were conclusive: You will hole a higher percentage of putts when you leave the flagstick in.

The hits just keep on coming. From shortly before Christmas, we got this gift:

The Cliffs Notes at the end give it away: leave the flagstick in. It’s going to help you.

On January 16, we got a study from MyGolfSpy. Their conclusion: “Leave the pin in.”

All of these studies back our own study, conducted last year, and all conclude the same thing: leaving the flagstick in will help golfers to make more putts. (Our study tested putts that would roll at speeds carrying them between 3 and 6 feet past the hole, as some of these other tests continue to include the somewhat far-fetched nine feet past distances.)

The USGA and R&A, in proposing this Rule change, said that there “should be no advantage in being able to putt with the unattended flagstick in the hole.” They were wrong, and every study we’ve seen reaches the same conclusion: leaving the flagstick in is advantageous. We here at LSW conducted a study. Lou Stagner conducted a study. Dave Pelz has conducted two studies, in 1990 and in 2018. Others have conducted studies. They all reach the same conclusion: Leaving the flagstick in generally provides an advantage.

To golfers looking to shoot the lowest score, this is our advice:

• If the flagstick is leaning so much that a ball can’t fit* or it’s moving around in the hole due to high winds, take it out from short range or have it tended from long range (the flagstick and the person tending it can help with distance perception). These situations are incredibly rare.
• If you’re certain that you can control the ball speed to within about 3′ past the hole (at stimp 9.5), there’s no difference, so do whatever you like. A few of every hundred putts that would have gone in will be kept out, but about an equal number of putts that would have popped out will go in. There’s no real net advantage or disadvantage.
• For every foot that your ball has the potential to roll further than 3′ past the hole, the advantage of leaving the flagstick in grows. Balls that would miss will go in or stay closer to the hole than they otherwise would have.
• Additionally, consider that there may be times when you want to leave the flagstick in for shorter putts for two reasons. Not only do you have the option to hit the putt more firmly to take out some break, but because it may help you aim more precisely: you can aim at the “right edge of the flagstick” or even use the shadow cast by the flagstick as an alignment aid.

In other words, if you face a 40-foot putt, leave or put the flagstick in. Put the flagstick in if you have a very slippery downhill 15′ putt that could roll well past the hole. Put the flagstick in when you want to take away some of the break on a tricky four footer – plus the flagstick will give you more specific points at which to aim. For almost everything else, do as you like.

Putting with the flagstick in is an advantage. Use it.

* The 2019 Rules define a ball leaning against the flagstick as holed if any part of the ball is below the surface of the green, so even a flagstick leaning toward you so much that a ball won’t fit may not even be a good reason to pull the pin anymore, as a flagstick leaning toward you a little bit actually aids you even more as it deflects the ball downward and into the hole. This may actually just leave high winds as a time to take the flagstick out of the hole.

Later the day this article was originally published, we found this video from December 26, 2018:

MGS created this video:

Edoardo Molinari created his own test, the results of which you can see here, but in a later video with Mark Crossfield noted that “in is better” for putts hit at “very high speed.” He then defined “very high speed” as “four to five feet by.” Even on the PGA Tour, tens of thousands of putts are hit each year over 4′ by the hole.

Molinari’s testing is likely similar to this study by Cal Poly San Luis Obispo professor Tom Mase. His preliminary findings mirror Molinari’s in that well off-center putts that would be holed every time without a flagstick can occasionally be kicked out of the hole by the flagstick. We currently believe that, like Molinari’s study, these instances are fairly rare, and in a normal distribution of putts at a hole from farther ranges, would be more than made up for the by the times the flagstick helps. We’ll always go where the data leads us, but right now it is still solidly pointed in the direction of the advice above.

A brief aside on the Rules of Golf, the USGA, and the R&A:

We generally don’t find fault with much that these two organizations do. We find fault here, because they seemingly enacted a rule based on no actual information. We don’t feel that the USGA or R&A ever actually tested whether leaving the flagstick in provided an advantage or disadvantage, because we’re confident that had they done so, they would have found that there was an advantage.

We submitted feedback to the USGA as soon as we saw the Rule proposed, and we ran “flagstickrule.com” for a year to further oppose this proposed Rules change.

We can also see, if there was no advantage, how this Rules change might speed up the game, as it would allow someone who chipped close to just tap in, and would allow someone 50′ away to putt without fear of penalty while their playing companion finishes raking a bunker or something. Unfortunately, since there is an advantage, we fear the opposite may be true: this Rules change will slow down play. Think about – rather than taking the flagstick out once per green, and replacing it when everyone has holed out, smart golfers who realize and want to use the advantage putting with the flagstick in offers them will be replacing the flagstick when they putt from 28′ away after their buddy took it out from 32′. The flagstick might be taken out and replaced multiple times per hole, 18 times per round. That’s going to take much more time than the rare occasions when someone wanted to tap in or putt from 50′ away while their buddies were too busy doing other things to tend or pull the flagstick.

The USGA/R&A get a double bogey here, and it’ll be interesting to see how long this Rules change lasts.

P.S. PGA Tour players are not often valid sources of information. We advise not paying much attention to what they say – they’re great at what they do, and the “stigma” on Tour of putting with the flagstick in may take awhile to overcome. There are a lot of factors at play. We will note that Bryson DeChambeau, a relatively smart guy who doesn’t appear to care about what others think of him, is putting with the flagstick in fairly often, and Adam Scott is putting with the flagstick in ALL the time, as he feels it helps him aim his short putts and gives him more confidence.