To ensure that every player on the course is given a fair shake, rules and regulations govern equipment. Regulations placed upon golf balls monitor the weight, size and reaction of the ball.
Weight
The weight of a golf ball is carefully regulated to ensure that balls that are too heavy are not produced and used in an official capacity. The maximum weight for a ball is 1.62 ounces, and balls are not permitted to exceed this and still be used in tournament play. Most balls are manufactured to be close to this 1.62-ounce maximum weight, making it a safe estimate for the weight of a given ball.
Benefits
The benefits of weight on a ball come from the ball's ability to push through the air without being slowed. If you have ever hit a Wiffle ball, you can see how quickly a light ball the size of a golf ball stops when flying through the air. Adding weight to a ball would cause it to travel farther, making extra weight an unfair advantage.
Diameter
Golf balls have a minimum diameter of 1.68 inches, and similar to the weight restrictions, the diameter limits are closely adhered to. The benefits of a smaller diameter are twofold.
On the green, a smaller ball will be easier to hole out with, and while the benefit is minute, in time a smaller ball will equate to saved strokes on just-missed putts. Additionally, with a smaller surface area, the ball will have less response to wind resistance, again adding distance.
Construction
The construction of the ball, and the components used to create the ball, are also monitored to ensure that nothing being put into the ball is giving the player using it an unfair advantage. Innovations in the ball's construction have persisted, however, in a legal fashion with the implementation of multi-level cores aiming to maximize both the distance and control of the ball without sacrificing too much of one for the other.
Ball Stats
Even if a ball meets the legal requirements of the constitution of the ball and the dimensions of the ball, it is still possible for a ball to be failed and deemed illegal if it is found to provide an unfair edge, such as the ball's speed off the face of the club, distance in the air, and the total distance traveled, under controlled circumstances. Should any of these numbers be too high, the ball will not be approved.