What he found was surprising:
Many people claim that the short game and putting are the most important determinants of golf scores. For example, Pelz (1999, p.1) writes, “60% to 65% of all golf shots occur inside 100 yards of the hole. More important, about 80% of the shots golfers lose to par occur inside 100 yards.” Several academic studies have reached similar conclusions. In contrast, strokes gained analysis of PGA TOUR data shows that the long game is the most important factor explaining the variability in professional golf scores. . .Of the three components to the game -- long (>100 yards), short, and putting -- the contribution of the long game to shots gained (over the average player) is huge:
The availability of detailed golf shot data makes it possible to create golf measures that allow consistent comparisons between different parts of the game. Using the starting and ending locations of each shot, strokes gained gives the number of strokes a golfer gains or loses relative to an average PGA TOUR tournament field. Analysis of over eight million shots on the PGA TOUR in 2003-2010 shows that the long game (defined as shots starting over 100 yards from the hole) accounts for more than two-thirds of the scoring differences between PGA TOUR golfers.
Using data from 2003-2010 for golfers with at least 120 rounds, the contributions to total strokes gained are 72%, 11% and 17% for the long game, short game and putting, respectively. By this measure, the long game explains more than two-thirds of the variation in total strokes gained.So when Justin Rose won the US Open yesterday, what you saw was the consequence driving in the fairway and long irons to the green, just as Broadie's research indicates is most important. Mickelson falling short resulted not from his short game -- though missed putts and a thin sand wedge from the green made for good TV -- but his inability to hit the fairway and the poor position that placed him in for his long approaches.
The data show that Mickelson was 12th overall in both the long and short game and 95th in putting. This would suggest that he has the most to gain in improving his putting. However, when looked at in terms of strokes gained, Mickelson was almost a full stroke behind the Tour leader in the long game, 0.22 in the short game and 0.57 in putting.
If these findings hold today (would need updated data to determine) then this suggests that Phil has a lot more room for relative improvement in the long game than in putting and the short game combined.