YOU can usually tell when someone makes a living on the professional golf circuit.

The majority of the logoinfested elite players are immaculately turned out, the caddies have their own livery of shorts and unfeasibly large runners, while the coaches have a certain sophisticated windblown look. Except, that is, for Dave Pelz.

With his beard and his pale complexion, Pelz could be mistaken, say, for a NASA research scientist, which is probably understandable because he just happened to work as a physicist for the American space agency for the best part of 15 years.

But for most of that career crunching payload numbers, he was really a golfer in a white coat. A talented enough player to have won a scholarship to Indiana University, he found himself that indefinable amount short of making a living as a pro. But the lure of the game was too strong, and eventually in 1975, he quit physics and went back to something more complex.

But not as a competitor, as a teacher. And not as a conventional teacher either. With his grasp of data, and of why certain shots had a higher percentage success rate than others, he set himself up as a short-game specialist. If thousands of amateurs at his schools and clinics in the USA have listened to, and learned from his message, so have major champions such as Phil Mickelson, Vijay Singh and Mike Weir.

It was mentioned earlier this week when he announced that he was setting up his first Scoring Game School outside of America at Killeen Castle, the impressive new Jack Nicklaus-designed course in county Meath, that Pelz was a 30-year overnight sensation.

While his novel techniques aimed at improving putting and wedge play were common enough knowledge, he has moved more into the game's spotlight through his association with Mickelson.

Early in 2004 when the two first worked together, Mickelson had played in 42 majors and hadn't won one, but a few months later, he was slipping on the green jacket at Augusta National.

Since then, Mickelson has won two more titles with Pelz imbuing his star pupil with a more strategic approach to course management. "Phil was great before I got anywhere near him, he's one of the great wedge players that ever lived, " says Pelz. "So, I take no credit for what he has achieved."

If there were a few eyebrows raised when the game's most gifted short-game exponent decided to retain a short-game coach, Pelz explains that his advice is more statistically oriented than anything else. "It's not so much showing him how to grip the club, or how to execute the shot, it's more that I tell him which shots work in the majority of cases, and which don't. And Phil is a numbers guy, so if something works, he'll usually switch to it."

One set of statistics Pelz will be mindful of this week is Mickelson's dismal Open championship record of having played 13 times as a pro with just one top-10 finish.

That third place at Troon in 2004 is the only occasion that the left-hander has got himself into contention since he first competed back in 1993.

"Early in his career, Phil hit the ball high and hard with lots of spin, and that style has not won on many of the Open courses, " says Pelz. "So, we've been working on lower ball flight and a game which has minimum spin, but it's true that he has yet to prove himself on a links. Part of that is down to the problems he's had with his driver. He has just hit it so crooked off the tee, and that's why he changed instructors to Butch Harmon this year."

Having already spent three days with Mickelson at Carnoustie over last weekend, Pelz believes the course suits him. "There are lots of run-off areas were chipping comes into play, and it'll take a lot of talent to get up and down. During our practice sessions, he ran off the green maybe five or six times, and he was faced with a chip from a downhill lie to a pin well above him. So, he had to hit a high, soft shot, and Phil can probably do that better than anyone else in the world.

"His short game is better than it ever was, and he showed when he won at the Players Championship in May what he can do if he drives it well. So, if he has no problems from this wrist injury, I have high hopes for Carnoustie."