Software Economics - Phase Yield

Software Engineering
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Software Economics - Phase Yield

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  1. Software EconomicsPhase Yield

    Slide 1 - Software EconomicsPhase Yield

    • Emerson Murphy-Hill
    • Creative Commons Attribution 4.0 License.
    • Material Created by NCSU Software Engineering Faculty.
  2. Fault removal yield

    Slide 2 - Fault removal yield

    • Phase yield = removed in phase removed in phase + escapes from phase
    • Phases: design review, code, code review, compile, test
    • Phase escapes: defects injected before or during the phase, not found before or during the phase, and found later
    • The “escapes from phase” measure cannot be precisely calculated until after the program has been used in the field (need post-development defects) – need 20/20 hindsight
    • even then some failures can surface for years
  3. Fault Removal Yield Example

    Slide 3 - Fault Removal Yield Example

    • Phase
    • Injected
    • Removed
    • Cumulative Injected
    • Cumulative Removed
    • Requirements
    • 1
    • 0
    • 1
    • 0
    • Design
    • 5
    • 0
    • 6
    • 0
    • Design Review
    • 0
    • 3
    • 6
    • 3
    • Code
    • 15
    • 1
    • 21
    • 4
    • Code Review
    • 0
    • 8
    • 21
    • 12
    • Static Analysis
    • 0
    • 6
    • 21
    • 18
    • Test
    • 0
    • 3
    • 21
    • 21
    • Field
    • 0
    • 5
    • Total
    • 26
    • Design Review Yield = 3/(0+6) = 50%
    • Code Review Yield= 8/(8+9) = 47%
    • Process Yield = 21/26 = 81%
    • Note: the faults show up in the “injected” column if they were analyzed and removed prior to release.
  4. Slide 4

    • 100 errors
    • Inspection
    • (50%)
    • 50 errors
    • Testing (50%)
    • 25 errors
    • To
    • customer
    • Solo programming with inspection
    • 100 errors
    • Testing
    • (50%)
    • 50 errors
    • To customer
    • Testing(50%)
    • Solo programming without inspection or pair programming
    • PairProgramming
    • 50 errors
    • Testing(50%)
    • 25 errors
    • To customer
    • Paired team without inspection
    • Quality Assurance Filters - Examples
    • See course pack page 23