Ivars Peterson's MathTrek

August 18, 2003

Golf Clubs and Driving Distance

The last 20 years have seen remarkable changes in golf equipment: metal-headed drivers, forgiving irons, new putter variants, juiced golf balls, and more. Have these technology changes led to improved performance?

Anecdotal evidence certainly points to such improvements. In 1980, for example, the leader in driving distance on the Professional Golfers of America (PGA) Tour was Dan Pohl, who averaged 274.1 yards. In 2002, this value would have put Pohl into 158th place.

To gain some insight into changes in driving distance and accuracy, statistician Scott M. Berry of Sycamore, Ill., analyzed driving statistics from the PGA Tour over the last 24 years. His report appears in the current issue of Chance.

PGA officials have a protocol for determining a player's average driving distance. At each tournament, they select two holes where most players hit drivers. Typically, the holes are fairly flat and oriented in opposite directions to minimize wind effects. Officials record the length of each player's drive on each hole, and the average of the two distances is considered a player's average driving distance.

A player's driving accuracy is the percentage of times that he hits the fairway for all par-4 and par-5 holes.

Berry obtained data on average driving distance for 735 PGA Tour golfers going back to 1980. A plot of the data shows some interesting features. Average driving distances stayed fairly flat during the 1980s, with a slight increase toward the end of the decade. There was a slight decrease in the early 1990s, followed by a steady, strong increase in the median driving distance from 1993 to the present.

"In the current golf season, every single PGA Tour player has an average driving distance larger than the median player's average driving distance in 1993," Berry remarked. "The average driving distance of the median Tour player has increased 27.3 yards from 1993 to 2003."

Is the improvement due to equipment or a stronger pool of players? Berry looked at the data for the seven golfers included in at least 23 of the 24 seasons of data. He saw a similar pattern in their statistics.

"This is an interesting trend, especially because these golfers, all having been Tour players for at least 20 years, are getting older," Berry noted. "They are all at least 40 and hitting the ball farther than they ever have!"

Further analysis led Berry to conclude that changes in technology were largely responsible for the increase in driving distance in the last 10 years.

Has technology aided a golfer's ability to hit drives not only farther but also straighter? In this case, the trend wasn't as evident as it was in the case of driving distance. In 1980, the median driving accuracy was 62.4 percent. It increased to a high of 69.8 percent in 1998, then decreased in the following 5 years. The 2003 median of 65.7 percent is the lowest since 1990.

Nonetheless, overall accuracy is improving. Indeed, further analysis suggested a 5-percent increase over the last 20 years.

There's a tradeoff between distance and accuracy, however. The error in the angle at which you hit the ball to keep it in the fairway is smaller the farther the ball goes. Indeed, the data show that, despite the overall improvement in accuracy, there remains a negative correlation between driving distance and accuracy.

Golf courses used in professional tournaments are already adapting to new equipment and performance levels, with longer holes, tighter fairways, and other changes.

"The best drivers of today are almost 1.5 shots per round better than the best drivers of 1980, resulting in a 6-shot difference in a four-round tournament," Berry wrote in Chance.

In the sport of golf, that's huge.