This lecture is brought to you by the Dean of Criminal Rehabilitation & Eradication

Many challenges are now listed as 'Broad'. This means the probability of success increases linearly from 0 and up, with a roof on 100%. This is different from the previous system, 'Narrow', where the challenge only increased around +/- 5 levels from the challenge level.

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]

Probability CalculatorEdit

 template = Template:Calculator/Probability
 form = Probability
 result = ProbabilityResult
 param = quality|Quality Level||int|0-350
 param = diff|Difficulty Level|50|int|1-1000
 param = scaler|Difficulty Scaler (%)|60|int|1-100
Calculator loading...

The difficulty scaler for Fallen London is 0.60 (as of 9th Sept. 2013). This gives the 'base' probability of success (60%), 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
  • 91-100%: 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
  • 9-25: high-risk
  • 26-33: tough
  • 34-41: very chancy
  • 42-50: chancy
  • 51-59: modest
  • 60-67: very modest
  • 68-75: low-risk
  • 76+: straightforward

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

More CalculatorsEdit

Difficulty LevelEdit

Work out the likely difficulty level, given your probability and quality level:

 template = Template:Calculator/Difficulty Level
 form = Difficulty
 result = DifficultyResult
 param = quality|Quality Level||int|0-999
 param = prob|Success Probability (%)|50|int|0-100
 param = scaler|Difficulty Scaler (%)|60|int|1-100
Calculator loading...

Relative ProbabilityEdit

Given your current probability of success, what quality level will you need to achieve your desired probability?

 template = Template:Calculator/Relative Probability
 form = RelProbability
 result = RelProbabilityResult
 param = quality|Quality Level||int|1-250
 param = prob|Success Probability (%)||int|1-100
 param = prob2|Desired Probability (%)|80|int|1-100
Calculator loading...

Challenge List GeneratorEdit

 template = Template:Calculator/ChallengeList
 form = ChallengeGenerator
 result = ChallengeGeneratorResult
 param = qualLink|Quality Link|Dangerous|string
 param = diff|Difficulty Level|50|int|1-1000
 param = scaler|Difficulty Scaler (%)|60|int|1-100
Calculator loading...