Putting is Easier with the Flagstick In
Despite the USGA/R&A saying:
We do not believe this to be true. Just watch this video:
Note how easily Mike is able to bang the ball toward the hole, even with the flagstick leaning slightly toward him. He can "take out break" and just hit the flagstick, assured that the ball will slow significantly enough to drop. Many of his putts would have popped up in the air or lipped out entirely had the flagstick not been in the hole.
Unfortunately there is not a lot of data around. Dave Pelz conducted a study many moons ago that concluded:
We conducted a similar study using the Perfect Putter in the fall of 2016, and will seek to replicate that study this spring when we can get back out to a golf course.
Putting with the flagstick in, particularly from 3 to 6 feet, makes those putts significantly easier. Because even those knee knockers become almost tap-ins, this makes putting from 30 feet, 40 feet, and further away easier because rather than needing to hit the ball to two feet to guarantee a two-putt, golfers can hit the ball to a circle eight feet in diameter for a virtually assured two-putt.