Standard Ishikawa: Organizes root causes by category.

Weighted (FMEA-style): Each cause is given an RPN (Risk Priority Number) between 1-10. Higher RPN means higher priority.

Bayesian: Each cause has an independent probability of occurring [0.0 - 1.0]. The total probability of the Main Problem is calculated assuming causes are independent: \( P_{total} = 1 - \prod (1 - P_i) \).