Software Quality: An Overview From the Perspective of Total Quality Management By Kan, Basili and Shapiro

1.General Quality –necessary condition but not sufficient for today’s world market –multidimensional concept involving: entity of interest, view of that entity, quality attributes of that entity –Multiple definitions a) conformance to requirements (Crosby) and b) fitness for use (Juran) this is non-trivial to do

Software Quality (cont.) 2. Product Quality –two levels : small q - at product level –Defect rate (e.g. use “bugs/kloc” metric) –Reliability (e.g. use “meantime-to-failure” metric) Big Q - product level PLUS customer satisfaction level –quality loop concept: customer wants requirements product design and implementation according to requirements distribute and service the product customer satisfaction

Software Quality (cont.) 3. Process Quality: –Ensuring that each intermediate product resulting from the steps of development process is of good quality and satisfies the internal customers who have to perform the next step. –Ensuring that the methodology, tools, and technologies employed for the process are under control and are improving Need metrics for this ?---

Total Quality Management (TQM) A style of management that creates an organizational culture for improvement of –product –process –service to achieve success through customer satisfaction Key elements are: 1.Customer focus 2.Process 3.Human Culture 4.Measurements Several Organizational frameworks have been proposed to improve quality –Plan-Do-Check-Act (improving/optimizing a process) –Quality Improvement Paradigm/Experience Factory (building cont. improving org.) –SEI Capability Maturity Model (staged process improvement) –Lean Enterprise Management (“valued added” process and development)

1. Customer Focus Understanding the customers’ wants and needs is a key element for software TQM –Early in the development phase - verify requirements and early feedback: rapid throwaway prototyping iterative enhancement evolutionary development –Late in the development phase – controlled feedback customer beta test customer “burn-in” for early customers

2. Process, Technology, and Development Defect Prevention Process –causal analysis –action team –(action kick off meetings) –action tracking Reviews and Inspections Formal Methods Improvements in Design Paradigms (e.g. OO) Programming Languages Development Platforms, Libraries, Change Control and Middleware (Screen -Logic –DataBase; M-V-C) Software Reuse

3. Human Culture Organizational Participation (total) –Management commitment and leadership –Professional buy-in and empowerment –customer interaction (my addition for emphasis) Integrated Operational Approach –project (schedule/resource/function perspective) –process –quality Communication is a “huge” factor for human culture Many software projects are “group” activities -- social, psychological, organizational skills are relatively important

4. Data, Measurement, and Model Collecting data and performing measurements are absolutely necessary –well defined metrics (a necessary pre-req.) Goal/Question/Metric (GQM) –“models” are needed reliability models quality models (may be used for both development and service) complexity models service models (my addition) –must have means to collect and record –collected information needs to be valid & reliable,