Software defect discovery curve calculator

Calculate observed discovery curve [day,new,cumulative] and OLS discovery-count slope with your own figures.

Your numbers

Use the units shown. Results update as you change valid inputs.

Use observed discovery curve [day,new,cumulative] and OLS discovery-count slope to compare changes to your inputs. The method and limits below explain the scope.

Examples

Examples

Try the starting example

JSON Unique defect observations [ID,test-day index]
[["D1",1],["D2",1],["D3",2],["D4",3]]
Observed discovery curve [day,new,cumulative]
[[1,2,2],[2,1,3],[3,1,4]]
OLS discovery-count slope (defects/day²)
-0.5
OLS count intercept (defects/day)
2.333333

Try another scenario

JSON Unique defect observations [ID,test-day index]
[["D1",1],["D2",2],["D3",2],["D4",3],["D5",3]]
Observed discovery curve [day,new,cumulative]
[[1,1,1],[2,2,3],[3,2,5]]
OLS discovery-count slope (defects/day²)
0.5
OLS count intercept (defects/day)
0.666667
Calculation method

Calculation method

Observed discovery curve [day,new,cumulative]

Group unique defect IDs by supplied day and cumulatively sum counts.

OLS discovery-count slope (defects/day²)

Regress observed daily new-defect counts on observed day indices with equal day weight.

OLS count intercept (defects/day)

mean(count)−slope×mean(day); one distinct day gives slope zero.

Symbols and units
a
JSON Unique defect observations [ID,test-day index]

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

  • Descriptive observed-day linear trend only. Untested days must not be treated as zero observations; no total-defect or release-readiness prediction. Supported limits: 1–1000 distinct defect IDs. One chosen build cohort per run.
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