The 2016 Masters Tournament is in the history books. Jordan Spieth had what some are calling an epic meltdown on the final 9 holes of the tournament and, in a come-from-behind victory, Danny Willett earned the green jacket. The tournament is touted as a tradition unlike any other.™ Edge-of-your seat drama aside, does this tradition actually represent a stable process?
The tournament that began in 1934 is held at the same course every year. Augusta National is a par 72 course. Unlike most other golf courses in the US, Augusta National has never been rated, although it has been unofficially rated twice by a team assembled by Golf Digest at 76.2.and 78.1. A control chart of the average of the four winning rounds from 1934 to 2016 reveals that collectively the winners have beaten par, averaging 69.87.
Using all of the data to create the control limits in the above chart, two out-of-control situations are revealed: a run above the mean from 1956-1963 and a run below the mean from 1990-1998. If not for 1999, which is slightly above the mean, we would have witnessed 16 consecutive years below the mean. Given the increase in the quality of competition and improvements in golf equipment over the past 80 plus years, it isn’t too surprising that scores have decreased.
The second chart below defines The Masters winning golf scores as two processes, one from 1934 to 1973, and a second 1974 to 2015. Creating two sets of limits does eliminate the out-of-control situations that appeared in the previous chart, but a new out- of-control condition appears on the range chart for 1989. This is the year that Nick Faldo, another Englishman, won his first Masters. After scoring a third-round 77 in the midst of bad weather, he took advantage of Scott Hoch’s now infamous choke, and closed with a fourth round 65. He switched putters before that last round, a fruitful move (to the tune of $200,000). That new putter helped him score the low round of the tournament and sink a birdie putt to win in a sudden death playoff with Hoch.
So which control chart appears more useful to you? It likely depends on what question you are trying to answer.
If you are looking for signals in the data so that you can investigate causes of trends, the first chart might be the better choice. Was the Augusta course altered in 1956 in a way that caused scores to go up? Did the introduction of the stainless steel driver cause scores to fall in the early 1990s?
If you want to highlight the overall improvements, both in winning scores and in reduced variation, you might find the second chart useful. Or, it may just be your ticket to that new putter.