1. CHAPTER 9 INSPECTIONS AS AN UP-FRONT QUALITY TECHNIQUE

2. WITH PROPER INSPECTIONS
EARLY SKEPTIC
BELIEVER
FIRST HAND EXPERIENCE
WITH PROPER INSPECTIONS
AND ITS REWARDS

3. AGENDA: 1 Anatomy of Inspection.
Inspection Team
Inspection Phases
Inspection Types
Wrap-up
2 Lessons learned through the evolution
of the Inspection process.
3 Inspection Metrics
4 The National perspective
5 Examples of Payoff

4. Anatomy Of Inspection Primary Purpose Secondary Purposes
“..to remove defects as early as possible in the development process.”
Secondary Purposes
Trace requirements to design.
Provide a technically correct base for next phase of development.
Increase programming quality
Increase product quality
Decrease life cycle cost
Increase effectiveness of test activity
Provide first indication of maintainability
Encourage entry/exit criteria software management

5. Anatomy Of Inspection…
Inspection Team
MANAGER
MODERATOR
INSPECTORS
READER
AUTHOR

6. Inspection Phases Planning: Starting Phase The moderator will
Establish conduct & progress for entire process.
Identify team members and roles
Assure that materials to be inspected are available and conform to standards.
Determine entry criteria is met.
Determine need for overview.
Schedule meeting time and place.
Provide team with materials, resources and meeting notice.

7. Inspection Phases… Overview: Discretionary Phase The Author:
Gives a brief description of the product, its functionality and interfaces.
The Attendees:
Get familiar with product before the inspection
The Moderator:
Conducts the overview meeting.
Provides the inspection package to the team.
Gives inspection meeting notice.

8. Inspection Phases… Preparation:
Begins at least 5 days before inspection meeting.
Lead time to allow inspectors to examine the material for all possible defects.
Time spent – as much as duration of inspection meeting – maximum of 2 hours.
Inspectors record the defects and the time spent in preparation.
Reader prepares to present the material to the team.
Reader records any difficulties in understanding the material.

9. Inspection Phases… Inspection Meeting: The main event
Team meets to inspect the product.
Moderator ensures proper conduct of the meeting.
Reader presents the product to the team in a systematic manner.
Team identifies, discusses, validates and records the defects detected.
Moderator decides if re-inspection is required.
Moderator logs records of preparation and inspection times, defects found and re-inspection requirement.
Moderator sends the findings to author and SQA.

10. Inspection Phases… Rework: Follow-Up:
Author examines the defects and makes the necessary fixes.
Author verifies the fixes and informs moderator.
Moderator determines if re-inspection required.
Follow-Up:
Moderator assures that all defects logged have been fixed.
Moderator logs the verification and sends the summary to SQE.
Moderator declares inspection complete.

11. I0 I1 I2 INSPECTION TYPES SOFTWARE DEVELOPMENT PHASES REQUIREMENTS
PROGRAM
SPECIFICATIONS
LOW-LEVEL OR
DETAILED DESIGN
HIGH-LEVEL
DESIGN
CODE
IMPLEMENTATION I0 I2 I1

12. Inspection Types… High-Level Design Inspection I0:
Examine the HLD to verify that the specification has been correctly mapped to functional design.
Identify each requirement to process and task.
One I0 per mode.
Perform all six inspection phases.

13. Inspection Types… Low-Level Design Inspection I1:
Held for any module that is new, has structural or interface change, or 40% or more change in SLOC.
Verifies the detailed design before translation to code.
Perform all six inspection phases.
Coding begins only after the successful completion of this inspection.

14. Inspection Types… Code Inspection I2:
Held for all/selected new or changed code.
Code must compile cleanly.
Perform all six inspection phases.
Result of a successful I2 – Compiled code that conforms to requirements specifications, high-level and low-level design.
Testing begins only after the successful completion of this inspection.

15. Inspection Types…Some more
Requirements Inspections
Specification Inspections
Document Inspections
Salient Points:
Inspection is effective only when the product is presented in a standardized, structured form.
The results of these inspections, logged in a standardized form, can help the management in decision making.

16. Anatomy of Inspection – Wrap-up
Inspection Defect Types
Design Defects
Logic Defects
Syntax Defects
Standards Defects
Data Defects
Interface Defects
Return code/Message Defects
Prologue/Comment Defects
Requirements change Defects
Performance Improvement Defects

17. Inspections - Success Factors
Inspection Prerequisites
Technically competent and trained inspectors.
Trained moderator.
Proper planning and distribution of materials.
Good professional attitude.
Full preparation prior to inspection meeting.
Completed design or cleanly compiled code.
Updated resource requirements.
Training for managers to understand and gain from inspections.

18. AGENDA: 1 Anatomy of Inspection.
Inspection Team
Inspection Phases
Inspection Types
Wrap-up
2 Lessons learned through the evolution
of the Inspection process.
3 Inspection Metrics
4 The National perspective
5 Examples of Payoff

19. Lessons Learned
Keep the psychological factor in mind. – Help, don’t embarass!!!
Make inspections impersonal
Keep team size to small groups of peers
Make data collection consistent
Utilize only trained personnel.

20. Inspection Metrics Established by AT&T Bell Labs.
Defines nine metrics.
Help plan, monitor, control and improve code inspection process.
Helped to achieve >70% defect removal.
Used the Goal-Question-Metric paradigm to derive the nine metrics.

21. Inspection Metrics… GQM paradigm Identify measurement goal.
Pose specific question – in measurable terms – whose answer fulfills the goal.
Enumerate the metrics.
Example
Goal – Monitor and Control
Question – What is the quality of the inspected software?
Metric – Average faults detected per KLOC
- Average inspection rate
- Average Preparation rate

22. Inspection Metrics… Total KLOC Average lines of code inspected =
1000 x KLOC / #Inspections
Average Preparation rate =
1000 x KLOC / AvgInspectPrepTime
Average Inspection rate =
1000 x KLOC / TotInspectMeetingTime
Average Effort per KLOC =
TotInspectionEffort / KLOC

23. Inspection Metrics… (cont’d)
Average Effort per fault detected =
TotalInspectEffort / #Faults_Detected
Average Faults detected per KLOC =
#Faults_detected / KLOC
Percentage of re-inspections =
100 * #Re-Inspections / #Inspections
Defect removal efficiency =
100 x #Faults_Detected / #CodingFaults

24. AGENDA: 1 Anatomy of Inspection.
Inspection Team
Inspection Phases
Inspection Types
Wrap-up
2 Lessons learned through the evolution
of the Inspection process.
3 Inspection Metrics
4 The National perspective
5 Examples of Payoff

25. National Software Quality Experiment
Reasons for the experiment
Quality has become a national goal.
Software Engineering is maturing.
Aware consumers demand higher quality.
Aggressive quality goals at corporate level.
Experiment
27 inspections labs
327 trained professionals
90,925 SLOC inspected using packaged procedures.
22, 828 minutes of preparation effort
5,464 minutes of inspection time
1,849 defects detected

26. Examples of Payoff AT&T Bell Laboratories Bell Northern Research
Adopted Nine Metrics based on GQM paradigm
Reduced cost of fault removal by 300%
Defect Removal Efficiency of +70%
Bell Northern Research
Inspections give 1 defect per person-hour invested – 2-4 times faster than testing
1 person-hour of code inspection saves 33 person-hours of future maintenance effort.

27. Examples of Payoff… Large Satellite Comm System
The project was done in 1993.
330 KLOC on five target platforms with many COTS products.
73 inspection meetings over 4 months
#Defects recorded – 2,760
Cost Savings - $1 million
Cost to find and fix during test – Cost to find and fix via inspections prior to test

28. Examples of Payoff… Raytheon
Inspection = Defect Detection Process DDP + Defect Prevention Process DPP
Used DDP + DPP ( )
Rework cost decrease: 45% to 5-10%.
Increase software productivity 2.7x
Reduced negative deviation from budget and deadlines from 40% to near 0.
Reduced error density by factor of 3.

29. Final Words …
And
Questions???