[jedanbik]

Reminds me of risk analysis: Impact times Probability equals Risk.

Contagion seems like a probability factor. Impact is the cost of leaving things unchanged. Fix cost is the cost of fixing the problem.

Risk management in this context then means comparing Impact cost to Fix cost in terms of impact for the business.

[stouset]

The one difference is that contagion is multiplicative over time (potentially logarithmically, linearly, or exponentially—probably a reasonable definition for 1/5, 3/5, and 5/5 respectively).