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Many people joke about the poor quality of IT
products |
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People seem to accept systems being down
occasionally or needing to reboot their PCs |
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There are many examples in the news about
quality problems related to IT (See What Went Wrong?) |
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But quality is very important in many IT
projects |
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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 needs |
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Other experts define quality based on |
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conformance to requirements: meeting written
specifications |
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fitness for use: ensuring a product can be used
as it was intended |
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Quality planning: identifying which quality
standards are relevant to the project and how to satisfy them |
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Quality assurance: evaluating overall project
performance to ensure the project will satisfy the relevant quality
standards |
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Quality control: monitoring specific project
results to ensure that they comply with the relevant quality standards
while identifying ways to improve overall quality |
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Modern quality management |
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requires customer satisfaction |
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prefers prevention to inspection |
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recognizes management responsibility for quality |
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Noteworthy quality experts include Deming,
Juran, Crosby, Ishikawa, Taguchi, and Feigenbaum |
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Deming was famous for his work in rebuilding
Japan and his 14 points |
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Juran wrote the Quality Control Handbook and 10
steps to quality improvement |
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Crosby wrote Quality is Free and suggested that
organizations strive for zero defects |
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Ishikawa developed the concept of quality
circles and using fishbone diagrams |
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Taguchi developed methods for optimizing the
process of engineering experimentation |
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Feigenbaum developed the concept of total
quality control |
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The Malcolm Baldrige Quality Award was started
in 1987 to recognize companies with world-class quality |
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ISO 9000 provides minimum requirements for an
organization to meet their quality certification standards |
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It is important to design in quality and
communicate important factors that directly contribute to meeting the
customer’s requirements |
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Design of experiments helps identify which
variable have the most influence on the overall outcome of a process |
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Many scope aspects of IT projects affect quality
like functionality, features, system outputs, performance, reliability, and
maintainability |
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Quality assurance includes all the activities
related to satisfying the relevant quality standards for a project |
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Another goal of quality assurance is continuous
quality improvement |
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Benchmarking can be used to generate ideas for
quality improvements |
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Quality audits help identify lessons learned
that can improve performance on current or future projects |
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The main outputs of quality control are |
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acceptance decisions |
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rework |
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process adjustments |
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Some tools and techniques include |
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pareto analysis |
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statistical sampling |
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quality control charts |
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testing |
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Pareto analysis involves identifying the vital
few contributors that account for the most quality problems in a system |
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Also called the 80-20 rule, meaning that 80% of
problems are often due to 20% of the causes |
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Pareto diagrams are histograms that help
identify and prioritize problem areas |
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Statistical sampling involves choosing part of a
population of interest for inspection |
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The size of a sample depends on how
representative you want the sample to be |
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Sample size formula: |
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Sample size = .25 X (certainty Factor/acceptable
error)2 |
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Standard deviation measures how much variation
exists in a distribution of data |
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A small standard deviation means that data
cluster closely around the middle of a distribution and there is little
variability among the data |
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A normal distribution is a bell-shaped curve
that is symmetrical about the mean or average value of a population |
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A 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 control |
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Operating at a higher sigma value, like 6 sigma,
means the product tolerance or control limits have less variability |
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The 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 problems |
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Many IT professionals think of testing as a
stage that comes near the end of IT product development |
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Testing should be done during almost every phase
of the IT product development life cycle |
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A unit test is done to test each individual
component (often a program) to ensure it is as defect free as possible |
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Integration testing occurs between unit and
system testing to test functionally grouped components |
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System testing tests the entire system as one
entity |
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User acceptance testing is an independent test
performed by the end user prior to accepting the delivered system |
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Several suggestions for improving quality for IT
projects include |
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Leadership that promotes quality |
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Understanding the cost of quality |
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Focusing on organizational influences and
workplace factors that affect quality |
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Following maturity models to improve quality |
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“It is most important that top management be
quality-minded. In the absence of sincere manifestation of interest at the
top, little will happen below.” (Juran, 1945) |
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A large percentage of quality problems are
associated with management, not technical issues |
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The cost of quality is |
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the cost of conformance or delivering products
that meet requirements and fitness for use |
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the cost of nonconformance or taking
responsibility for failures or not meeting quality expectations |
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Prevention cost: the cost of planning and
executing a project so it is error-free or within an acceptable error range |
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Appraisal cost: the cost of evaluating processes
and their outputs to ensure quality |
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Internal failure cost: cost incurred to correct
an identified defect before the customer receives the product |
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External failure cost: cost that relates to all
errors not detected and corrected before delivery to the customer |
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Measurement and test equipment costs: capital
cost of equipment used to perform prevention and appraisal activities |
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Study by DeMarco and Lister showed that
organizational issues had a much greater influence on programmer
productivity than the technical environment or programming languages |
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Programmer productivity varied by a factor of
one to ten across organizations, but only by 21% within the same
organization |
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Study found no correlation between productivity
and programming language, years of experience, or salary |
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A dedicated workspace and a quiet work
environment were key factors to improving programmer productivity |
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Maturity models are frameworks for helping
organization improve their processes and systems |
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Software Quality Function Deployment Model
focuses on defining user requirements and planning software projects |
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The Software Engineering Institute’s Capability
Maturity Model provides a generic path to process improvement for software
development |
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Several groups are working on project management
maturity models |
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1. Ad-Hoc: The project management process is
described as disorganized, and occasionally even chaotic. The organization
has not defined systems and processes, and project success depends on
individual effort. There are chronic cost and schedule problems. |
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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. |
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3. Organized: There 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. |
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4. Managed: Management collects and uses
detailed measures of the effectiveness of project management. Project
success is more uniform, and cost and schedule performance conforms to
plan. |
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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. |
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