Equitable Stroke Control sets a maximum per-hole score that you can turn in for handicap purposes, and those per-hole maximums are based on your course handicap. For example, on that one disaster hole you might have taken 14 strokes (get to the practice range, buddy!) to get the ball in the cup. But based on your course handicap, ESC might require you to post only a "7" on the scorecard you submit to the handicap committee.
Including that 14 on your handicap score might throw your handicap index out of whack. And remember, the handicap index is not meant to reflect your average score, it's meant to reflect your best potential.
To determine the Equitable Stroke Control limits for your round, you must first know your course handicap. Once you've determined your course handicap, you can check the chart down below (which should also be available at golf courses) to determine the ESC per-hole maximums.
(If you are in the process of establishing a handicap index, you won't yet have a course handicap and therefore won't be able to use the chart below. Wait, yes you will! Use the USGA maximum handicaps - 36.4 for men, 40.4 for women - to determine course handicap.)
Keep in mind that Equitable Stroke Control is a function of the USGA Handicap System; it is used by golfers who carry USGA handicaps who are playing rounds that will be turned in to a handicap committee. If you do not carry a USGA handicap or are playing a round that you won't turn in for handicap purposes, ESC doesn't apply.
Also note that even when ESC limits are in use, golfers must still count all their strokes. If you score 89, you don't get to claim to your buddies that you shot 79 because of ESC limits. Your score is the number of strokes you used. But the score you submit to a handicap committee is the total that results after you apply Equitable Stroke Control (and that figure is known as your adjusted gross score).
Here is the chart that shows Equitable Stroke Control limits:
Equitable Stroke Control Chart
|Course Handicap||Maximum Score|
|40 or more||10|