“How safe?” or “How safe compared to plan?”
Figure *405: Diagram showing calculation of a Safety-Deviation for a performance Attribute. The Safety-Margin is relative to the target Level and the distance between the Baseline and the target. In this example, as the required Safety-Margin is 150%, it must be 50% beyond the target Level. The distance (x) is worked out from the distance between the target and the Baseline (2x).
2. Safety-Deviation expresses how far away the current design proposal, or Evo-Step implementation, is estimated to be from the desired safety Level. The higher the negative deviation is, the greater the “risk of failure” to deliver the target Level of the Attribute.
3. The Safety-Deviation can be used by technical management to monitor the progress of a design or a real Evolving project delivery. Management will need some Policy regarding setting and respecting Safety-Factors. They will need to set some Standards regarding the degree to which designs include planned Safety-Factors. This is a specific tactic for Risk management.
4. A Safety-Deviation is measured as a percentage difference between the estimated or actual Percentage-Impact and the Safety-Margin. Percentage values are usually used. It could however be expressed as the difference between the two Levels using the actual Units-of-Measure.
Assuming percentage values are being used,
5. When using the Value-Decision method, and a spreadsheet model, the Safety-Deviation computations can normally be done automatically using the values of the Requirements and the design Impacts. Automatic warning of insufficient safety is a possibility.
[Safety-Deviation *405]: X.±
This Concept entered by Adore.
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