A Forced Error is an error that stems from pressure created by the other player’s ball. This is different from the more familiar concept of the Unforced Error.

An Unforced Error is a mistake that a player makes on an easy or routine ball—the error stems from the player’s inability to execute what should be a simple stroke or return.

A player generates a Forced Error through pace or location, or a combination of both.

Forced Errors are critical statistics because they account for up to half or more of the points in most matches.

The Aggressive Margin

So tracking Forced Errors is critical. Once we start to track Forced Errors we can then combine them with the better known stats of Winners and Unforced Errors to calculate the second key stat, what is called the Aggressive Margin.

The Aggressive Margin is the total of a player’s Winners and Forced Errors minus his Unforced Errors.

For example, let’s say a player hits 10 Winners and generates another 10 Forced Errors. That’s plus 20. Let’s say he makes 10 Unforced Errors, that’s –10. Subtract the Unforced Errors from the Winners and Forced Errors (20-10 = 10.). That’s an Aggressive Margin of +10.

The Aggressive Margin can be a positive or a negative number. It shows whether a player is playing positive tennis, or simply relying on his opponent to make more errors than he.

Statistical tennis is the key to victory. The best players will win more points than they lose by playing correct patterns and making high percentage shot execution.

For example:

Nadal would be + 25 during a match and Top juniors + 10

Developing the ability to win points through positive shot making is the key to winning—and making sure you’re positive shot making exceeds your unforced errors.