Keystone Severity Formula
A formula that combines Keystone Index with substitutability to determine the urgency of protection needed.
A formula that combines Keystone Index with substitutability to determine the urgency of protection needed. Keystone Severity = KI × Substitution Difficulty. High impact with easy substitution is manageable; high impact with no substitution is existential risk.
When to Use Keystone Severity Formula
After calculating Keystone Index, use this formula to prioritize protection investments based on both impact and replaceability.
How to Apply
Calculate Keystone Index
Use the KI formula to determine impact-to-resource ratio.
Assess Substitution Difficulty
Score replaceability: Immediately substitutable (0.1), Substitutable with effort (0.5), Difficult to substitute (2), Functionally irreplaceable (10).
Multiply for Severity
Keystone Severity = KI × Substitution Difficulty score.
Prioritize Response
Severity > 100 requires immediate protection. Severity > 500 represents existential dependency requiring multi-year recovery if lost.