Intimidate and Persuade are conversation options that sometimes appear when you speak to various people in Dragon Age: Origins. These options are sometimes only unlocked if you have the Coercion skill, and their success depends on the Strength or Cunning attributes of your main character, and how many levels of Coercion your main character has.
Both intimidation and persuasion work by testing against a coercion check. Here's how it works, based on information from the Intimidate and Persuade forum thread.
- Persuade uses Cunning
- Intimidate uses Strength
- The system takes a look at the skill and subtracts 10 from the attribute.
- Each level of coercion you have adds 25 to the number that the system checks against.
- If the combined score is higher than the coercion check difficulty you pass. Otherwise you fail.
- The highest difficulty check in the game is 100, so getting 4 points of Coercion skill means you should pass all tests in the game regardless of your Cunning or Strength.
Based on the above you should be able to determine just how many points of Coercion you need to pass most or all tests in the game.