| Fault
Breakdown |
| Project Phase |
| Faults found (%) |
| Effort (%) |
| Specification |
| 3.25 |
| 5 |
| Z proof |
| 16 |
| 2.5 |
| High-level
design |
| 1.5 |
| 2 |
|
|
| Detailed
Design, Code & informal |
|
| test |
|
| 26.25 |
| 17 |
| Unit test |
| 15.75 |
| 25 |
| Integration test |
| 1.25 |
| 1 |
| Code proof |
| 5.25 |
| 4.5 |
| System
validation test |
| 21.5 |
| 9.5 |
| Acceptance test |
| 1.25 |
| 1.5 |
| Other (e.g.
management & training) |
| 8 |
| 32 |