Examples
Examples
Try the starting example
- External dependencies: name, supplied failure probability %
- API,10 CDN,20
- Projects: name, value lost on dependency failure $, required dependencies joined by |
- Shop,100,API|CDN Blog,50,CDN
- Named failure scenario, comma-separated, or none
- API
- Total expected project loss ($)
- $38.00
- Expected loss by project ($)
- Shop: 28; Blog: 10
- Project value exposed to each dependency ($)
- API: 100; CDN: 150
- Dependencies required by multiple projects
- CDN
- Loss in named failure scenario, counting each project once ($)
- $100.00
Try another scenario
- External dependencies: name, supplied failure probability %
- API,10 CDN,20
- Projects: name, value lost on dependency failure $, required dependencies joined by |
- Shop,100,API|CDN Blog,50,CDN
- Named failure scenario, comma-separated, or none
- API,CDN
- Total expected project loss ($)
- $38.00
- Expected loss by project ($)
- Shop: 28; Blog: 10
- Project value exposed to each dependency ($)
- API: 100; CDN: 150
- Dependencies required by multiple projects
- CDN
- Loss in named failure scenario, counting each project once ($)
- $150.00
Calculation method
Calculation method
Total expected project loss ($)
For each project, assume independent listed dependency failures and compute 1−product(1−p); multiply by entered project loss and sum projects.
Expected loss by project ($)
Show each project’s union-failure expected loss.
Project value exposed to each dependency ($)
Sum entered project values requiring each dependency; do not add these exposures to obtain total loss because projects can overlap.
Dependencies required by multiple projects
List dependency nodes with at least two distinct dependent projects.
Loss in named failure scenario, counting each project once ($)
A project incurs its entered loss once if any required dependency is in the supplied failure set.
Symbols and units
- a
- External dependencies: name, supplied failure probability %
- b
- Projects: name, value lost on dependency failure $, required dependencies joined by |
- c
- Named failure scenario, comma-separated, or none
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Assumptions & limits
Assumptions & limits
- A two-level project/dependency loss model with externally supplied failure risks. Dependency failures are assumed independent for expected-loss calculation; projects can share dependencies. Cascades, partial losses and actual service reliability are not inferred.
Are these inputs private?
These calculations run in your browser. A shared link contains the values you choose to share. Only questions submitted to the separate AI finder are sent to OpenAI.
Further reading
OpenStax: arithmetic and geometry ↗
Background reading; this does not imply endorsement or independent review of SumFizz.