Once you have calculated effective skill by applying all relevant modifiers to base skill, roll 3d to determine the outcome. If the total rolled on the dice is less than  or equal to your effective skill, you succeed, and the difference between your effective skill and your die roll is your margin of success.

Example: If you have effective skill 18 and roll a 12, you succeed; your margin of success is 6.  

If you roll higher than your effective skill, you fail, and the difference between the die roll and your effective skill is your margin of failure.

Example: If you have effective skill 9 and roll a 12, you fail; your margin of failure is 3.

Always note your margin of success or failure, as many rules use these margins to calculate results that matter in play. Even when the rules don’t call for these  numbers, the GM might wish to reward a large margin of success with a particularly favorable outcome, or assess especially dire consequences for a large margin of failure!

Extremely high or low rolls have special effects – beyond those for normal success and failure – regardless of your exact margin of success or failure.

Critical Success

A critical success is an especially good result. You score a critical success as follows:

• A roll of 3 or 4 is always a critical success.
• A roll of 5 is a critical success if your effective skill is 15+.
• A roll of 6 is a critical success if your effective skill is 16+.

When you roll a critical success, the GM determines what happens to you. It is always something good! The lower the roll, the better “bonus” he gives you.
A critical hit is a critical success scored on an attack. The GM does not determine the result. Instead, use the Critical Hit Table (p. 556).

Critical Failure

A critical failure is an especially bad result. You score a critical failure as follows:

• A roll of 18 is always a critical failure.
• A roll of 17 is a critical failure if your effective skill is 15 or less; otherwise, it is an ordinary failure.
• Any roll of 10 greater than your effective skill is a critical failure: 16 on a skill of 6, 15 on a skill of 5, and so on.

When you roll a critical failure, the GM determines what happens to you. It is always something bad – the higher the roll, the worse the result.

A critical miss is a critical failure scored on an attack. The GM does not determine the result. Instead, use the Critical Miss Table (p. 556).