Broad difficulty

For the sake of conciseness, many challenges are now listed merely as 'Broad', with an attribute and a number attached (the Difficulty Level). Here's how this works.

The probability of success for a 'Broad' challenge relies on three things: the Level of the Attribute or Quality being tested, the Difficulty Level, and the Difficulty Scaler, as follows:


 * Probability of success = (Scaler) * (Quality Level) / (Difficulty Level). [rounded down]

The difficulty scaler for Fallen London is 0.65 (as of 28th March 2013), although this seems liable to change. This gives the 'base' probability of success (65%), which occurs when the Quality Level equals the Difficulty Level.

The following adjectives are used to describe the difficulty of a particular challenge, based on the calculated probability:
 * 0-10%: almost impossible
 * 11-30%: high-risk
 * 31-40%: tough
 * 41-50%: very chancy
 * 51-60%: chancy
 * 61-70%: modest
 * 71-80%: very modest
 * 81-90%: low-risk
 * 90-100%: straightforward

e.g. a Broad challenge on Shadowy with a difficulty level of 50 would currently have the following chances of success:
 * 0-8: almost impossible
 * 9-23: high-risk
 * 24-31: tough
 * 32-39: very chancy
 * 40-46: chancy
 * 47-54: modest
 * 55-62: very modest
 * 63-69: low-risk
 * 70+: straightforward

For further reading, this Story Nexus reference describes this rather less drily.