CIF301 Project Quality Unit 6

Project Quality Introduction “Quality” is generally agreed to be a good thing Often the use of procedures that will help ensure a systems quality will be lacking Quality systems must be defined Metrics should be used to check quality systems

The importance of software quality Increasing criticality of software The intangibility of software Accumulating errors during software development

Defining software quality Should be three specification for software quality a functional specification describing what the system does a quality specification concerned with how the system operates a resources specification concerned with how much will be spent on the system

ISO 9126 Published in 1991 Provides a definition for software quality Is seen as the base on which more detailed standards can be built

ISO 9126 ISO 9126 defines six software quality characteristics Functionality which covers the functions that a software product provides to satisfy a user needs Reliability which relates to the capability of the software to maintain its level of performance

ISO 9126 Usability Efficiency Maintainability Portability which relates to the effort needed to use the software Efficiency which relates to the physical resources used when the software is executed Maintainability which relates to the effort needed to make changes to the software Portability which relates to the ability of the software to be transferred to a different environment

Software quality measures Reliability Could measure availability mean time between failures failure at time of operation number of faults dealt with

Software quality measures Maintainability Closely related flexibility Extendibility Ease with which new features can be added to the software

Product versus process quality management What is the difference? Why is this important? Often one or the other is looked at Both should always be considered

BS EN ISO 9001 This is the standard for quality management systems Current standard BS EN ISO 9001:2000 This is a family of standards. 2000 series superseded 1994 series Standard grew out of DEF STAN 05-21 and BS5750 There are other related quality standards

BS EN ISO 9001 BS EN ISO 9000 is a group of standards: 9000, fundamentals and vocabulary 9001, Quality Management Systems requirements 9004, guidelines for performance improvement 9001 is the standard that applicants are assessed against. It is a general standard that can be applied to any business or organisation

TickIT The BS EN ISO 9000 series of standards refers to quality management systems in general In the UK, the Department of Trade and Industry (DTI) have formulated the TickIT standards. The TickIT standards give an interpretation of the BS EN ISO 9001 standard as it specifically applies to software development.

TickIT The main requirements of Tick IT are: A detailed development plan is required before development is embarked upon. Change control procedures should be used at all stages of development Design reviews must take place The suitability of the design methodology must be reviewed

TickIT main requirements of Tick IT (cont.) Progress must be reviewed on a systematic basis It must be possible to trace back the features of software design to specifications and requirements Designs must be properly documented

TickIT main requirements of Tick IT (cont.) Suitable test plans, specifications and records must be produced A code of practice must be in place that governs the way the software is developed

TickIT The code of practice must include the following: The design must be broken down into levels, each with identifiable inputs and outputs. Software must be organised into modules. A module must normally perform a single function or a set of related functions. A plain language description must exist for each module.

TickIT A TickIT auditor will certify that a particular organisation conforms to the standard The process is referred to as certification The TickIT scheme is now administered by a division of the British Standards Institute on behalf of the DTI

Capability Maturity Model Developed in US by The Software Engineering Institute, Carnegie Mellon University. The Capability Maturity Model attempts to place an organisation producing software at one of five levels.

Capability Maturity Model Level 1: Initial Level 2: Repeatable Level 3: Defined Level 4: Managed Level 5: Optimizing

Capability Maturity Model Level 1: Initial The procedures followed tend to be haphazard. Some projects will be successful, but this tends to be because of the skills of particular individuals including project managers. There is no level 0 and so any organization would be at this level by default.

Capability Maturity Model Level 2: Repeatable Organizations at this level will have basic project management procedures in place. The way an individual task is carried out will depend largely on the person doing it Level 3: Defined The organization has defined the way in which each task in the software development cycle is to be done.

Capability Maturity Model Level 4: Managed The products and processes involved in software development are subject to measurement and control. Level 5: Optimizing Improvement in procedures are designed and implemented using the data gathered from the measurement process

Ways to help enhance software quality Increasing visibility checking each others code proposed by Weinberg in 1971in what he termed “egoless programming” Procedural Structure Checking intermediate stages

Conclusion IT Project Quality Quality definitions ISO 9126 BS EN ISO 9001 TickIT The capability maturity model Enhancing software quality