As a culture, we crave hyperbole. "Best ever," "worst ever," "most amazing" and so on. I say that to frame the fact that Jason Day's 2016-17 was the best putting season in recorded PGA Tour history, and we actually have the data to back this up.

Strokes gained is a complicated-sounding stat, but it's really not that complicated at all. Here is a definition from the man who crated the stat, Mark Broadie:

The new "strokes gained-putting" stat measures the number of putts a golfer takes relative to the PGA Tour average, taking into account the initial putt distance on each green. In 2010 Luke Donald led the Tour with 0.871 strokes gained. That means in each round, he gained an average of 0.871 strokes on the field just from his superior putting ability. Here's how the stat is computed. Suppose, for example, a golfer one-putts from 33 feet. The Tour average to hole-out from that distance is 2.0 putts, so a one-putt gains one putt on the field. A two-putt neither gains nor loses, but a three-putt represents a loss of one putt (or stroke) against the field.

From other distances, the strokes gained or lost are typically fractional. For example, suppose a golfer one-putts from eight feet. The Tour average from that distance is 1.5, so a one-putt gains 0.5 strokes, but a two-putt loses 0.5 strokes. If the golfer started from eight feet 10 times in the round and made half of them, his strokes gained would be zero—. He gained 0.5 on five holes and lost 0.5 on the other five holes. If the golfer made six and missed four, his strokes gained would be one—. He gained 0.5 on six holes and lost 0.5 on four holes. That makes sense because he took a total of 14 putts vs. the Tour average of 15 putts.

So with that in mind, let's look at the best strokes-gained putting seasons in recorded PGA Tour history which stretches back to 2004 (this is when ShotLink was brought into play which was able to measure distances from hole and calculate the data).

  1. Jason Day (2016): 1.13
  2. Jesper Parnevik (2007): .979
  3. Corey Pavin (2008): .973
  4. Ben Crane (2005): .939
  5. Luke Donald (2009): .934
  6. Graeme McDowell (2014): .882
  7. Tiger Woods (2009): .877

This is outrageous. It means Day gained an average of 1.13 strokes per round over an average PGA Tour player. This equates to 4.5 strokes a week. What's even crazier is that the golfer who finished second (Jordan Spieth) could only muster a .758 number.

Even nuttier: Phil Mickelson finished ninth in strokes gained putting, and his average strokes gained were exactly half (.565) of Day's. Day putted twice as good as the ninth-best putter on the PGA Tour in 2016. Insanity.