Green reading: speed and line.

How much does reading matter?

A study by Jon Karlsen and Johnny Nilsson, part of Karlsen's 2010 doctoral thesis at the Norwegian School of Sport Sciences, is summarised as having tested 43 highly skilled golfers and concluded that green reading matters more than stroke technique for skilled players. We could not open the thesis summary itself, so treat that conclusion as unconfirmed; the percentages attributed to the study are left out here for the same reason. The stroke side of putting is on the putting page; this page is about the read.

Speed: how hard to hit it

Pelz's 17 inches and the "lumpy donut"

Dave Pelz described a ring of footprints within about six feet of the hole, left by golfers walking up to retrieve their balls. He called it the "lumpy donut", and it can knock a slow-moving putt off line (GOLF.com, 2021). His answer was pace: hit the putt firmly enough that, if it missed, it would finish about 17 inches past the hole. That is enough speed to roll through the donut without shrinking the effective size of the hole too much.

Too firm makes the hole smaller

TrackMan data reported by GOLF.com in 2020 shows the cost of hitting it harder. The faster a ball arrives, the more likely it is to lip out. On a flat green running at about 10 on the Stimpmeter:

Taken together: Pelz argued that some speed past the hole helps, and the TrackMan figures show how much of the target a firmer putt gives away.

Downhill or uphill?

Physicist A. Raymond Penner ("The physics of putting", Canadian Journal of Physics, 2002) found that downhill putts are much more likely to be holed than equivalent uphill putts, as reported by Inside Science in 2015. That runs against a common preference: golfers tend to say they would rather leave themselves an uphill putt.

Line: where to aim

Aim just past the hole

Physicist Robert Grober, as reported by Inside Science, says the ideal aiming point is just beyond the hole. Lines from putts struck from different positions meet above the hole and form a diamond-shaped aiming zone. That zone shrinks as putts get longer.

Do golfers under-read?

Dave Pelz is reported to have found that recreational golfers usually under-read the break on putts. That claim rests on a single secondary account of his research, so treat it as unconfirmed.

AimPoint Express

AimPoint Express was developed by coach Mark Sweeney as a simpler version of his earlier AimPoint system (Golfweek, David Dusek, April 2024). As Golfweek describes it, the player straddles the line about halfway to the hole to feel the slope through the feet, then holds up one finger per percent of slope at arm's length to find the aim point.

Sweeney told Golfweek that the finger method came from teaching children, and that testing showed one finger per percent was accurate to within an inch or two from 20 feet. That is the developer's own claim and has not been independently confirmed. Secondary sources also describe the finger scale in different ways (Keiser University College of Golf and Golf Digest Middle East give differing versions), so learn the method from an instructor who teaches it rather than from a summary.

Golfweek's 2024 list of AimPoint users included Max Homa, Will Zalatoris, Viktor Hovland, Keegan Bradley, Tommy Fleetwood, Collin Morikawa and Adam Scott. Tiger Woods, Jordan Spieth and Jason Day were named among those who do not use it.

Reading greens within the Rules

Under the 2023 Rules of Golf, in effect from 1 January 2023, Rule 13.1e says you must not deliberately rub the green or roll a ball to test it during a round. The exceptions are the green you have just finished and practice greens between holes.

Rule 5.6b asks players to play at a prompt pace, including the time spent preparing for each stroke, and in stroke play allows "ready golf" when it is safe. The R&A says the next edition is due on 1 January 2028. See pace of play and the putting green.