Quality Models in Software Engineering Literature: An Analytical and Comparative Study Rafa E. Al-Qutaish, PhD Al Ain University of Science and Technology – Abu Dhabi Campus Journal of American Science 2010 工科所 N 張柏欽 工科所 N 林弘緯 1

Outline Introduction Model Review McCall’s Quality Model Boehm’s Quality Model Dromey’s Quality Model FURPS Quality Model ISO 9126 Quality Model Model Analysis Discussion 2

Outline Introduction Model Review McCall’s Quality Model Boehm’s Quality Model Dromey’s Quality Model FURPS Quality Model ISO 9126 Quality Model Model Analysis Discussion 3

Introduction The quality of software products is now considered to be an essential element in business success. For some sensitive systems, the software quality is essential since the poor quality may cause tremendous human loss. 4

Introduction Definition of “Software Quality” IEEE(1990) The degree to which a system, component or process meets specified requirements and customer (user) needs (expectations) Pressman(2004) Conformance to explicitly stated functional and performance requirements, explicitly documented development standards, and implicit characteristics that are expected of all professionally developed software ISO(1999) The totality of characteristics of an entity that bear on its ability to satisfy stated and implied needs Petrasch(1999) The existence of characteristics of a product which can be assigned to requirements 5

Outline Introduction Model Review McCall’s Quality Model Boehm’s Quality Model Dromey’s Quality Model FURPS Quality Model ISO 9126 Quality Model Model Analysis Discussion 6

Model Overview McCall’s Quality Model(1977) The most known quality model originates from the US military Model aim to bridge the gap between users and developers Three major perspectives Product Revision Product Operations Product Transitions The metric is computed by answering “yes” or “no” questions 7

Model Overview Product Transition Maintainability Flexibility Testability Product Operations Correctness Reliability Efficiency Integrity Usability Product Transition Portability Reusability Interoperability 8

Model Overview McCall’s Quality Model(1977) Product revision Maintainability Testability Flexibility Modularity Self-descriptiveness Conciseness SimplicityYes : 50% No:50% 9

Model Overview Boehm’s Quality Model(1976) High Level Requirements of actual use Intermediate Level Qualities expected from a software system lowest-level (primitive) characteristics provide the foundation for defining quality metrics Metric A measure of extent or degree to which a product possesses and exhibits a certain (quality) characteristic 10

Model Overview-Boehm’s Quality Model 11

Model Overview Dromey’s Quality Model Product Based Quality evaluation 12

Model Overview Dromey’s Quality Model 13

Model Overview FURPS Quality Model(Robert Grady, 1992) Has been extended by IBM Rational Software FURPS+ design constraints requirements implementation requirements interface requirements physical requirements FURPS Functionality Usability Reliability Performance Supportability 14

Model Overview ISO 9126 Quality Model(1991) Software Product Evaluation – Quality Characteristics and Guidelines for Their Use History ISO IS : Quality Model [ISO, 2001] ISO TR : External Metrics [ISO, 2003] ISO TR : Internal Metrics [ISO, 2003] ISO TR : Quality in Use Metrics [ISO,2004] 15

Model Overview Two parts quality model Internal and external quality model Quality in use model 16

Model Overview Two parts quality model Internal and external quality model Quality in use model 17

Model Overview Quality in the lifecycle 18

Outline Introduction Model Review McCall’s Quality Model Boehm’s Quality Model Dromey’s Quality Model FURPS Quality Model ISO 9126 Quality Model Model Analysis Discussion 19

Model Analysis Common Factor Distinct Factor 20

Outline Introduction Model Review McCall’s Quality Model Boehm’s Quality Model Dromey’s Quality Model FURPS Quality Model ISO 9126 Quality Model Model Analysis Discussion 21

Discussion McCall’s Quality Model Bridge the gap between users and developers Boehm’s Quality Model Requirements of actual use Dromey’s Quality Model Product Based/Quality evaluation FURPS Build for IBM Rational Software Company ISO 9126 Quality Models National Standard 22

Discussion McCall’s Quality Model has the most specific definitions of the metrics FURPS may not suit to most software systems since it’s build for a certain company Since each model has its distinguish features, model use could depend on which character you are Program Manager McCall’s Model Developer(Programmer) ISO Model Overview Dromey’s Model 23