1、Chapter 7:Project Quality ManagementQuality of Information Technology ProjectsMany people joke about the poor quality of IT products People seem to accept systems being down occasionally or needing to reboot their PCsThere are many examples in the news about quality problems related to IT (See What
2、Went Wrong?)But quality is very important in many IT projectsWhat Is Project Quality Management?The International Organization for Standardization (ISO) defines quality as the totality of characteristics of an entity that bear on its ability to satisfy stated or implied needsOther experts define qua
3、lity based on conformance to requirements: meeting written specifications fitness for use: ensuring a product can be used as it was intendedProject Quality Management ProcessesQuality planning: identifying which quality standards are relevant to the project and how to satisfy themQuality assurance:
4、evaluating overall project performance to ensure the project will satisfy the relevant quality standardsQuality control: monitoring specific project results to ensure that they comply with the relevant quality standards while identifying ways to improve overall qualityModern Quality ManagementModern
5、 quality management requires customer satisfaction prefers prevention to inspection recognizes management responsibility for qualityNoteworthy quality experts include Deming, Juran, Crosby, Ishikawa, Taguchi, and FeigenbaumQuality ExpertsDeming was famous for his work in rebuilding Japan and his 14
6、pointsJuran wrote the Quality Control Handbook and 10 steps to quality improvementCrosby wrote Quality is Free and suggested that organizations strive for zero defectsIshikawa developed the concept of quality circles and using fishbone diagramsTaguchi developed methods for optimizing the process of
7、engineering experimentationFeigenbaum developed the concept of total quality controlFigure 7-1. Sample Fishbone or Ishikawa DiagramMalcolm Baldrige Award andISO 9000The Malcolm Baldrige Quality Award was started in 1987 to recognize companies with world-class qualityISO 9000 provides minimum require
8、ments for an organization to meet their quality certification standardsQuality PlanningIt is important to design in quality and communicate important factors that directly contribute to meeting the customers requirementsDesign of experiments helps identify which variable have the most influence on t
9、he overall outcome of a processMany scope aspects of IT projects affect quality like functionality, features, system outputs, performance, reliability, and maintainabilityQuality AssuranceQuality assurance includes all the activities related to satisfying the relevant quality standards for a project
10、Another goal of quality assurance is continuous quality improvementBenchmarking can be used to generate ideas for quality improvementsQuality audits help identify lessons learned that can improve performance on current or future projectsQuality ControlThe main outputs of quality control are acceptan
11、ce decisions rework process adjustmentsSome tools and techniques include pareto analysis statistical sampling quality control charts testingPareto AnalysisPareto analysis involves identifying the vital few contributors that account for the most quality problems in a systemAlso called the 80-20 rule,
12、 meaning that 80% of problems are often due to 20% of the causesPareto diagrams are histograms that help identify and prioritize problem areasFigure 7-2. Sample Pareto DiagramStatistical Sampling and Standard DeviationStatistical sampling involves choosing part of a population of interest for inspec
13、tionThe size of a sample depends on how representative you want the sample to beSample size formula:Sample size = .25 X (certainty Factor/acceptable error)2Table 7-1. Commonly Used Certainty FactorsDesired CertaintyCertainty Factor95%1.96090%1.64580%1.28195% certainty: Sample size = 0.25 X (1.960/.0
14、5) 2 = 38490% certainty: Sample size = 0.25 X (1.645/.10)2 = 6880% certainty: Sample size = 0.25 X (1.281/.20)2 = 10Standard DeviationStandard deviation measures how much variation exists in a distribution of dataA small standard deviation means that data cluster closely around the middle of a distr
15、ibution and there is little variability among the dataA normal distribution is a bell-shaped curve that is symmetrical about the mean or average value of a populationFigure 7-3. Normal Distribution and Standard DeviationTable 7-2. Sigma and Defective UnitsSpecification Range(in +/- Sigmas)Percent of
16、PopulationWithin RangeDefective UnitsPer Billion168.27317,300,000295.4545,400,000399.732,700,000499.993763,000599.99994357699.99999982Note: “Six sigma” often refers to +/-3 sigma, meaning2.7 million defects per billion units produced, or 2.7defects per million.Quality Control Charts, Six Sigma, and
17、the Seven Run RuleA control chart is a graphic display of data that illustrates the results of a process over time. It helps prevent defects and allows you to determine whether a process is in control or out of controlOperating at a higher sigma value, like 6 sigma, means the product tolerance or co
18、ntrol limits have less variabilityThe seven run rule states that if seven data points in a row are all below the mean, above,the mean, or increasing or decreasing, then the process needs to be examined for non-random problemsFigure 7-4. Sample Quality Control ChartFigure 7-5. Reducing Defects with S
19、ix SigmaTestingMany IT professionals think of testing as a stage that comes near the end of IT product developmentTesting should be done during almost every phase of the IT product development life cycleFigure 7-6. Testing Tasks in the Software Development Life CycleTypes of TestsA unit test is done
20、 to test each individual component (often a program) to ensure it is as defect free as possibleIntegration testing occurs between unit and system testing to test functionally grouped componentsSystem testing tests the entire system as one entityUser acceptance testing is an independent test performe
21、d by the end user prior to accepting the delivered systemFigure 7-7. Gantt Chart for Building Testing into a Systems Development Project PlanProject 98 fileImproving Information Technology Project QualitySeveral suggestions for improving quality for IT projects include Leadership that promotes quali
22、ty Understanding the cost of quality Focusing on organizational influences and workplace factors that affect quality Following maturity models to improve qualityLeadership“It is most important that top management be quality-minded. In the absence of sincere manifestation of interest at the top, litt
23、le will happen below.” (Juran, 1945)A large percentage of quality problems are associated with management, not technical issuesThe Cost of QualityThe cost of quality is the cost of conformance or delivering products that meet requirements and fitness for use the cost of nonconformance or taking resp
24、onsibility for failures or not meeting quality expectationsTable 7-3. Costs Per Hour of Downtime Caused by Software DefectsBusinessCost per Hour DowntimeAutomated teller machines (medium-sized bank)$14,500Package shipping service$28,250Telephone ticket sales$69,000Catalog sales center$90,000Airline
25、reservation center (small airline)$89,500Five Cost Categories Related to QualityPrevention cost: the cost of planning and executing a project so it is error-free or within an acceptable error rangeAppraisal cost: the cost of evaluating processes and their outputs to ensure qualityInternal failure co
26、st: cost incurred to correct an identified defect before the customer receives the productExternal failure cost: cost that relates to all errors not detected and corrected before delivery to the customerMeasurement and test equipment costs: capital cost of equipment used to perform prevention and ap
27、praisal activitiesOrganization Influences, Workplace Factors, and QualityStudy by DeMarco and Lister showed that organizational issues had a much greater influence on programmer productivity than the technical environment or programming languagesProgrammer productivity varied by a factor of one to t
28、en across organizations, but only by 21% within the same organizationStudy found no correlation between productivity and programming language, years of experience, or salaryA dedicated workspace and a quiet work environment were key factors to improving programmer productivityMaturity ModelsMaturity
29、 models are frameworks for helping organization improve their processes and systems Software Quality Function Deployment Model focuses on defining user requirements and planning software projects The Software Engineering Institutes Capability Maturity Model provides a generic path to process improve
30、ment for software development Several groups are working on project management maturity modelsProject Management Maturity Model1. Ad-Hoc: The project management process is described as disorganized, and occasionally even chaotic. The organization has not defined systems and processes, and project su
31、ccess depends on individual effort. There are chronic cost and schedule problems.2. Abbreviated: There are some project management processes and systems in place to track cost, schedule, and scope. Project success is largely unpredictable and cost and schedule problems are common.3. Organized: There
32、 are standardized, documented project management processes and systems that are integrated into the rest of the organization. Project success is more predictable, and cost and schedule performance is improved.4. Managed: Management collects and uses detailed measures of the effectiveness of project
33、management. Project success is more uniform, and cost and schedule performance conforms to plan.5. Adaptive: Feedback from the project management process and from piloting innovative ideas and technologies enables continuous improvement. Project success is the norm, and cost and schedule performance is continuously improving.
