Compression can affect the speed, spin and trajectory of a shot. But compression is just one design element of many. Just knowing the compression of your golf ball will not tell you anything about its performance without understanding the layers, materials, dimple pattern, and other construction characteristics.  

The term compression has two different meanings in golf. As a design element, compression is a numerical measurement of the stiffness or softness of the golf ball, or any spherical object that is part of the golf ball design.

Compression can also refer to the club and ball interaction at impact. The amount of compression occurring at impact is dependent on clubhead speed, club selection, and the golf ball. Higher speeds deflect or compress the ball more and lower speeds deflect the ball less. 

It’s important to note that everyone measures compression differently. Golf ball manufacturers use different methods and devices. And compression is not a requirement of the USGA and R&A, and the rules of golf do not include compression specifications.