THE NUMBERS, EXPLAINED
How to use this calculator.
Use the same observation period, severity grouping and deduplicated defect definition for both lists. Rates are descriptive, not causal.
Start with your inputs
Enter pre-release defects by severity (counts), post-release defects by severity (counts). Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Pre-release defects by severity (counts) | 8,18 |
| Post-release defects by severity (counts) | 2,2 |
A worked example
With the example inputs above, escape rates by severity (%) is 20, 10. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| Escape rates by severity (%) | 20, 10 |
| Overall escape rate (%) | 13.333333 |
How this is calculated
Escape rates by severity (%)
Divide escaped defects by all defects in each severity group.
Overall escape rate (%)
Divide total post-release defects by total defects.
Symbols and units
- a
- Pre-release defects by severity (counts)
- b
- Post-release defects by severity (counts)
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Assumptions and limits
Use the same observation period, severity grouping and deduplicated defect definition for both lists. Rates are descriptive, not causal.
Calculations use the values you enter. Blank or invalid inputs show an error instead of silently substituting zero. Results are displayed to useful precision; calculations retain the underlying numeric precision.
Questions about this tool
What does the result tell me?
Escape rates by severity (%); Overall escape rate (%). The result applies to the method and inputs described above. Check the units and assumptions before using it in a decision.
Why might another calculator differ?
Differences in units, rounding, timing or model definitions can produce different answers. Compare the input definitions and the method, rather than only the final number. For this tool: Use the same observation period, severity grouping and deduplicated defect definition for both lists. Rates are descriptive, not causal.
Are my inputs stored or sent to AI?
Calculations on this page happen in your browser. The separate AI question finder sends its submitted conversation to OpenAI; these calculator fields are not sent. Favourites and recent tool names are stored locally. A shared link contains the inputs you choose to include.
Further reading
OpenStax Prealgebra 2e — arithmetic and proportions ↗
Background reading; this does not imply endorsement or independent review of SumFizz.
Review status
Software example and browser checks are recorded in our quality report. No external expert review is claimed. Created with coding assistance; calculations run as ordinary browser code.
Read the quality report →