Personal Software Process Team Software Process CSC 3380 Lecture 08

Sources Introduction to the Personal Software Process by Watts S. Humphery, pp. 239-273, Introduction to the Team Software Process by Watts S. Humphery

Product Quality Can’t retrofit a product to improve quality From the beginning we need: Quality standards; Process standards; Quality assurance mechanisms, responsibilities Defect elimination is the principal metric Done by reviews, compilation, and testing Each such filter passes on a %age of defects Testing is most expensive and least effective

Product Quality continued Problems with testing Hard to trace back from symptom to defect Defects interact to mask each other Tests are often enormous - testing is “blind”, so we must test for every category of defect You never know that a product is defect-free Keep individual/organization estimated filter rates Individual review may not exceed 70% effectiveness - prototyping helps eliminate rest, which often arise in requirements, specification, and design errors

Filtering yields of different methods Individual Code review 70% to 80% Group Code Inspection 50% to 70% Compilation 50% Unit Testing 40% to 50% Integration Testing 45% Requirements (System) Testing Algorithm Testing 8%

Process Quality As quality improves, removal rates decrease Defect removal strategy: Individuals develop high quality modules Team inspects all module interfaces and interactions Team validates all requirements and their presence in code Individual conducts very complete unit test Team does comprehensive integration testing QA does thorough system testing

Process Quality Build in as much quality as you want to buy Quality failure costs – fixing defects Quality appraisal costs – reviews and other filtering that doesn’t remove defects Defect prevention costs – process analysis and improvement efforts Failure costs ~ compile and test costs Appraisal costs ~ reviews Personal process metrics Appraisal/failure > 2.0 (primary metric) Review yield >= 70% (use own checklist) When achieved, cull checklist and do prototyping

Major Insights of Introductory Team Software Process Teams are the norm; they speed up development,bring skills/experience to bear Teamwork is synergistic; this requires: Training and experience Common goals and good communication Acceptance of assigned roles Environmental support (management) Accepted process, including planning Commitment to all the above Mutual respect and support Teams are fun and satisfying as well as productive

The Team Process Launch sets goals, roles, meeting schedule Strategizing sets conceptual design, risk assessment, development strategy, estimates Planning sets detailed plans and QA process Requirements definition sets specifications and mechanisms for requirements change Design sets standards, product design, test plans, and performs reviews, inspections Implementation completes low-level design, coding, reviews, inspections, testing

The Team Process continued Integration and system testing tests and validates product, produces documentation Postmortem evaluates experience, analyzes process, provides suggestions for improving Team roles: Leader Development manager Planning manager Quality/process manager Support manager