Strokes gained golf stats.  What are they?

If you've followed the PGA Tour in recent years you would have noticed that they've made a switch from the old style golf stats to strokes gained rankings.

If you look at this graphic of Jordan Spieth's 2016/2017 rankings, you will see that these are all measured in strokes gained.  So what are strokes gained stats? Well, it's basically a player's performance versus a benchmark, with the benchmark being the average performance by a tour player. A strokes gained number of zero, would then mean a player is performing exactly like the average player on tour.

Strokes gained stats are used by the PGA Tour as well as the European Tour. The PGA Tour has hundreds of volunteers each week that collect information about each shot every player hits via their Shotlink system.  Because they have so much information they can calculate the effective par for every shot a player might face, be that a 3 foot putt or a 169 yard shot from the rough.

The par for a 3 foot putt is therefore calculated at 1.02 and a 7 foot putt has a par of 1.5. What this basically means is that the average tour player would make 98 out of a hundred three foot putts missing just two. From 7 feet that number would drop to 50 out of 100, so this gives you a par of 1.02 and a par of 1.5 for these respective distances. 

So how do you then calculate strokes gained or lost per shot?  The formula is really quite simple.  Take the starting par of a given shot, subtract 1 for the shot the player just hit and then subtract the remaining par. The result is then the strokes gained or lost for that specific shot.

If you then want to calculate the total strokes gained for putting for the round, you simply add all the pluses and minuses of all putts hit on the day and you'll get a total for the round.

If we then use a specific example of a player that makes a 7 foot putt, the calculation will be as follows.   Starting par of 1.5, minus 1 shot hit by the player, minus the remaining par which would be 0 in this case.  This then adds up to +0.5 for the putt or a gain of 0.5 shots on the field.

If we had to calculate the strokes gained or lost for a longer shot, in this case a 137 yard shot that was hit to 7 feet at the famous 17th hole at Sawgrass it would look as follows.

A starting par of 2.93 (137 yards), minus 1 shot hit by the player, minus 1.5 (par from 7 feet) which then gives us a +0.43 or a gain of 0.43 shots on the field for the shot.

Hopefully this gives you a better idea of what strokes gained stats are and why it is so useful for the professional golfers.