What it measures
Club Path describes which way the clubhead is traveling, left or right, at the instant the ball is most compressed against the face. It follows the geometric center of the clubhead, not the spot on the face where the ball was struck, and is given in degrees relative to the target line. Path is a snapshot of that one instant, which makes it different from Swing Direction, which describes the whole arc across the bottom of the downswing.
For a right-handed golfer, a positive number means the club is moving to the right of the target, often called in-to-out. A negative number means it is moving to the left, or out-to-in. Zero means the club is moving straight down the target line. Left-handed golfers see the same sign rule applied to the target line, so their in-to-out path reads negative.
Typical numbers
There is no single tour average for path, because tour players shape shots both ways and lefts and rights would cancel out. What stands out with skilled players is control: stock shots usually come from a path within a few degrees of zero, and many coaches prefer a deliberate path of a few degrees in one direction, matched by the face, rather than chasing exactly zero.
Everyday golfers vary much more from swing to swing. Out-to-in paths are very common among higher handicaps, which is one reason the slice is the most common miss for that group. Numbers in the minus 5 to minus 10 range are not unusual for a slicer, but this varies widely from player to player.
What changes it
The direction of the swing arc is the biggest factor: an over-the-top move sends path left and a swing that comes from inside sends it right. Attack angle matters too. Hitting down on the ball shifts path to the right, and hitting up shifts it to the left, because the ball is struck before or after the bottom of a tilted arc. With longer, flatter clubs this shift is close to one degree of path per degree of attack angle; with shorter, more upright clubs it is smaller.
Ball position works through the same geometry. A ball played farther back is met earlier in the arc, which tends to push path right; a ball played forward tends to pull it left. Alignment of the feet, hips and shoulders also nudges path in the direction they point.
What it changes
Path on its own does not decide where the ball goes. It has a small effect on start direction, roughly 15 percent with a driver and about 25 percent with an iron, with the face doing the rest. Its bigger job is curvature: the gap between face and path (Face to Path) sets the tilt of the spin axis, and the ball curves away from the path.
Because path is half of the Face to Path equation, a path far from zero forces the face to match it closely or the ball curves a lot. A very in-to-out path with a slightly closed face hooks; a very out-to-in path with a slightly open face slices.
How to use it
Pick a path that suits your shot shape and aim for consistency, not a perfect zero. Read path together with Face Angle and Face to Path before changing anything.
Bay drill: lay an alignment stick or a headcover a few inches outside and slightly behind the ball, so an over-the-top swing would hit it. Hit ten 7 irons and watch the path number. Then try moving the ball one ball width back and forward and note how much the path moves with each position.