You’re not making enough putts, or at least we figure that much considering you clicked on this story. The issue, however, is that real improvement requires hours of practice, and most people don’t have the time, so you might resign yourself to being a mediocre or poor putter.

But what if you could make lasting improvement with less than an hour of practice each week? Sports biomechanist Dr. Sasho MacKenzie says it’s possible, as long as you practice the right way.

“If you can get two 15-minute sessions in a week, adding to a half-hour, that’s going to be massive,” MacKenzie told Golf Digest+ members on a recent Golf Digest Happy Hour.

MORE: The science behind swinging faster and holing more putts, according to Dr. Sasho MacKenzie

While most people practice putting by whacking a few balls around, MacKenzie says the key is to focus your time on the putts that statistics show matter most. “Based on Mark Broadie’s research with strokes gained, we know the putts that separate good putters from bad putters,” he said. “It’s not 30 footers, and it’s not three footers. Putts between four and seven feet are the biggest difference makers.”

To get the most out of your 15 minutes of practice, MacKenzie proposes a targeted session where you hit short putts of varying break and speed.

The 6-5-4-3 putting warmup

• Six putts between four and seven feet
• Five putts between eight and 11 feet
• Four putts between 11 and 17 feet
• Three putts between 17 and 30 feet

The reason these shorter putts are so crucial to scoring is something course-management guru Scott Fawcett calls the “three-foot, eight-foot, 32-foot idea.” From three feet, PGA Tour players average a shade over one stroke to hole out, according to Arccos data lead Lou Stagner. From eight feet, however, they average about 1.5 strokes to hole out, meaning they make roughly 50 percent of those putts.

So, when a tour player moves from three to eight feet, they’ve essentially lost half a stroke. However, this trend doesn’t continue at the same pace as putts get longer. The next half stroke isn’t lost until you get 32 feet away. In other words, “You lose your first half shot of value in five feet—going from three to eight feet away. You lose your next half shot of value going all the way from eight feet to 32 feet,” Fawcett says.

https://twitter.com/LouStagner/status/1521285675546460160/photo/1

Translation: Short putts are really, really important to scoring. Trying to make more mid-range putts, like 25 or 30 footers, is less important. These statistics are why MacKenzie says most of your putting practice should be on shorter putts. It’s the idea at the center of his new Stack Putting System, which gives golfers 18 different putts, most of which are inside 17 feet. He says if you have extra time, you can work on distance control on long putts, but prioritize these short ones first.

Crucial to this plan is mixing up whether a putt is uphill or downhill, or breaking left or right. Each putt, even the ones at the same distance, should be from a different spot so that you aren’t simply grooving your stroke on one specific putt.

“It’s not random, even though it appears random,” MacKenzie said. “We are systematically targeting the types of putts that matter most. It’s practicing smarter, not just longer.”

This article was originally published on golfdigest.com