Plans and Expected Outcome

The Reference Line :

The first step was to perform "Defect Analysis of Past Projects" in order to create a reference line for the PIE.
We analysed 1336 defects from the baseline project (TETRA Release 1) and two other projects (to increase the statistical significance). A detailed Root Cause Analysis on all the defects was performed, and the Beizer Taxonomy was used as the "classification vehicle".
Analysis was done to five of the development phases, namely :

Based on this analysis, specific Defect Prevention solutions were determined for each of these phases.

The Beizer Taxonomy used for the classification includes ten major categories, each of which is divided into three levels, resulting in a 4-digit number which specifies unique defects.
The ten top level categories are :

  1. Planning
  2. Requirements and Features
  3. Functionality as Implemented
  4. Structural Bugs
  5. Data
  6. Implementation
  7. Integration
  8. Real-Time and Operating System
  9. Test Definition or Execution Bugs
  10. Other
The causes of the defects as determined by the engineers doing the classification, fall into four major categories: In creating the reference line, detailed interviews with 24 software engineers took place, in order to fully understand the reason for each defect, to classify the cause and to understand how the defect could have been prevented.
This "data mining" was performed on all the defects, resulting in a series of "classification tables" and a good Pareto analysis of the most common problems.

The following Pareto represents the breakdown (in descending order) of the defect analysis according to the Beizer Taxonomy top level categories :

Requirements and Features (1xxx) 47%

Functionality as Implemented (2xxx) 13.5%

Structural Bugs (3xxx) 9.3%

Implementation (5xxx) 8.3%

Data (4xxx) 6.9%

Integration (6xxx) 5.7%

Real time and Operating system (7xxx) 4.9%

Test definition or Execution bug (8xxx) 4.3%

Within each development phase in the baseline project, we further classified the defects, based on the Beizer Taxonomy.
For example, in the Requirement Specifications Phase, the second level breakdown of the main defects was as follows:
Requirement Completeness (13xx) 37.5%

Requirement Presentation (15xx) 34.7%

Requirement Changes (16xx) 11.2%

Requirement Incorrect (11xx) 8.7%

The third level breakdown of the main "Requirement Completeness" defects was :
Incomplete Requirements (131x) 73.4%

Missing, unspecified requirements (132x) 11.2%

Overly generalised requirements (134x) 4.6%

The same type of data analysis was performed for each of the five development phases selected for the PIE.

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Plans & expected outcome
Starting scenario
 Implementation of the improvement actions