Disastrousness is a noun that means the quality, state, or degree of being disastrous (causing great distress, ruin, calamity, or severe failure)

You're describing a classification of controls based on their relationship to other controls — typically used in internal control, audit, risk management, or information security frameworks. Here's a clear breakdown:

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1. Redundant (Equal)

Definition: A control that duplicates the function of another control — same objective, same coverage, same effect.

• 🔹 Relationship: Equal / identical purpose
• 🔹 Effect: If one fails, the other still achieves the objective
• 🔹 Value: Backup / defense-in-depth
• 🔹 Example: Two independent approvers required for the same transaction; two firewalls performing identical filtering

2. Compensating (Substitute)

Definition: A control that substitutes for another control that cannot be implemented or is ineffective.

• 🔹 Relationship: Substitute / alternative
• 🔹 Effect: Achieves the same risk-reduction objective through different means
• 🔹 Value: Provides equivalent assurance when the primary control is impractical
• 🔹 Example: Manual reconciliation instead of automated three-way match; segregation of duties achieved through supervisory review when staff is limited

3. Completing (Additional — Not Mandatory)

Definition: A control that fills a gap to make another control complete or effective, but is not itself required.

• 🔹 Relationship: Supplementary / enabling
• 🔹 Effect: Enhances or finishes the risk response
• 🔹 Value: Makes the primary control work as intended
• 🔹 Example: A review step that validates an automated control's output; documentation requirement that makes an approval control auditable

4. Complementing (Additional — Not Mandatory)

Definition: A control that adds further risk reduction beyond what is required — enhancing but not essential.

• 🔹 Relationship: Supplementary / reinforcing
• 🔹 Effect: Adds extra assurance or defense-in-depth
• 🔹 Value: Strengthens overall control environment; not strictly necessary
• 🔹 Example: Extra monitoring dashboards; additional training beyond policy minimum; trend analysis supporting a core control

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Quick Comparison Table

Type	Relationship	Mandatory?	Same Objective?	Effect if Removed
Redundant	Equal	No	Yes	No impact (duplicate)
Compensating	Substitute	Yes*	Yes	Risk exposure (primary missing)
Completing	Additional	No	Enables primary	Primary becomes ineffective
Complementing	Additional	No	Enhances	Slightly reduced assurance

*Compensating controls are mandatory in the absence of the primary control.

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Key Distinctions

• Redundant vs. Compensating: Redundant = both exist and work together; Compensating = one replaces the other.
• Completing vs. Complementing: Completing = necessary for another control to function; Complementing = nice-to-have enhancement.

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Would you like this applied to a specific framework (COSO, ISO 27001, SOX, Basel)?

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