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Software Project Management

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Software Project Management (CS615)
LECTURE # 42
10.Quality
10.1
Quality Concept
What is it? It's not enough to talk the talk by saying that soft ware quality is
important, you have to (1) explicitly define what is meant when you say 'software
quality, (2) create a set of activities that will help ensure that every software
engineering Work product exhibits high quality, (3) perform quality assurance
activities on every software project, (4) use metrics to develop strategies to
improving your software process and as a consequence the quality of. the end
product.
Who does it? Everyone involved in the software engineering process is
responsible for quality.
Why is it important? You can do it right, or you can do it over again. If a
software team stresses quality in all software engineering activities, it reduces the
amount of rework that it must do that results in lower costs, and more importantly,
improved time-to-market.
What are the steps? Before software quality assurance activities can be initiated,
it is important to define 'software quality' at a number of different levels of
abstraction, Once you understand what quality is, a software team must identify a
set of SQA activities that will filter errors out of work products before they are
passed on.
What is the work product? A Software Quality Assurance Plan is created to
define a software team's SQA strategy. During analysis, design, and code
generation, the primary SQA work product is the formal technical review
summary report. During testing, test plans and procedures are produced. Other
work products associated with process improvement may also be generated.
How do I ensure that I've done it right? Find errors before they become
defects! That is, work to improve your defect removal efficiency, thereby
reducing the amount of rework that your software team has to perform.
SQA encompasses:
(1) A quality management approach
(2) Effective software engineering technology (methods and tools)
(3) Formal technical reviews that are applied throughout the software process
(4) A multi-tiered testing strategy
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(5) Control of software documentation and the changes made to it
(6) A procedure to ensure compliance with software development standards
(when applicable)
(7) Measurement and reporting mechanisms.
Software quality is defined as conformance to explicitly stated functional and
performance requirements, documents, and standards. The factors that affect
software quality are a complex combination of conditions that can be measured
based on data, such as audit-ability, completeness, consistency, error tolerance,
and expandability.1n addition, this data includes hardware independence,
software system independence, modularity, security, and simplicity.
Software quality assurance is a planned and systematic approach necessary to
ensure the quality of a software product. Software reviews filter the product of all
errors. Software reviews can be conducted at all stages in the DLC of a software
product, such as analysis, design, and coding.
Testing is an important element of SQA activity. There are various testing tools to
automate testing process. The SQA plan is used as the template for all SQA
activities planned for a software project and includes details of the SQA activities
to be performed during project execution.
SCM is used to establish and maintain integrity of software items and ensure that
they can be traced easily. SCM helps define a library structure for storage and
retrieval of software items. SCM helps assess the impact of a recommended
change and make decisions depending on the costs and benefits. SCM needs to be
performed at all phases in the DLC of a software project.
The various SCM activities are identifying changes, controlling changes,
controlling versions, implementing changes, and communicating changes. These
activities are independent of the supervision of the project or the product
manager. This is to ensure objectivity in SCM. The scope of SCM is not limited
by code and includes requirements, design, database structures, test plans, and
documentation. SCM procedures vary with the project.
10.2
Producing quality software
As we have seen, one of the main problems in producing quality software is the
difficulty in determining the degree of quality within the software. As there is no
single widely accepted definition for quality, and because different people
perceive quality in different ways, both the developer and the customer must
reach agreement on metrics for quality' (this is discussed in more detail later). The
method of measuring quality may differ for different projects.
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This problem is discussed in a paper by Wesselius and Ververs (1990), in which
they conclude that complete objectivity in quality assessment cannot be achieved.
They identify three distinct components of quality:
An objectively assessable component
A subjectively assessable component
A non-assessable component
The quality of a product is objectively assessable when the characteristics of the
product, as stated in the requirements specification, can be identified.
The quality of a product is subjectively assessable when the characteristics of the
product comply with the customer's expectations.
The quality of a product is non-assessable when it behaves according to our
expectations in situations that have not been foreseen.
Wesselius and Ververs suggest that, for the quality of a software product to be
assessable, as many characteristics as possible should be moved from the
subjective and non-assessable components to the assessable component.
Essentially, this means that the requirements specification must describe as many
measurable characteristics of the product as possible.
Experience supports Wesselius and Ververs' conclusions. Badly defined
requirements are always a source of dispute between developer and customer.
Well-defined, detailed and measurable requirements minimize disputes and
disagreements when the development of the product is complete.
However, many development methods have a prolonged interval between the
specification of requirements and the delivery of the product (refer to Chapter 4
for a discussion of the software development cycle). The determination of quality
should not be postponed until development is complete. Effective software quality
control requires frequent assessments throughout the development cycle. Thus,
effective quality control coupled with a good requirements specification will
clearly increase the quality of the final product.
10.3
Quality Control
Variation control may be equated to quality control. But how do we achieve
quality control? Quality control involves the series of inspections, reviews, and
tests used throughout the software process to ensure each work product meets the
requirements placed upon it.
Quality control includes a feedback loop to the process that created the work
product. The combination of measurement and feedback allows us to tune the
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process when the work products created fail to meet their specifications. This
approach views quality control as part of the manufacturing process.
Quality control activities may be fully automated, entirely manual, or a
combination of automated tools and human interaction. A key concept of quality
control is that all work products have defined; measurable specifications to which
we may compare the output of each process. The feedback loop is essential to
minimize the defects produced.
10.4
Quality Control Myths
The establishment of effective quality control frequently encounters various
misconceptions and myths, the most common of which is related to the cost
effectiveness of quality control. Cobb and Mills (1990) list several of these myths,
and suggest methods of combating them. Two of the more prevalent myths
identified by Cobb and Mills are described below.
Myth: Quality costs money. This is one of the most common myths (not only in
software development). In fact, quality in software usually saves money. Poor
quality breeds failure. There is a positive correlation between failures and cost in
that it is more expensive to remove execution failures designed into software than
to design software to exclude execution failures.
Myth: Software failures are unavoidable. This is one of the worst myths
because the statement is partly true, and is therefore often used as an excuse to
justify poor quality software. The claim that `there is always another bug' should
never be a parameter in the design or implementation of software.
As these myths lose ground in modern approaches to software development, the
demand for suitable quality control standards and procedures increases. The IEEE
issued their first standard for software quality assurance plans in 1984 (IEEE
.1984), followed by a detailed guide to support the standard, issued in 1986. The
US Department of Defense issued a separate standard 2168 for defense systems
software quality programs (DOD 1988b), which forms a companion to the famous
US DOD standard 2167A (DOD 1988a) for defense systems software
development. The European ISO standard 9000-3, of 1990 (ISO 1990) gives a
broader meaning to the term quality assurance and covers configuration control
too.
10.5
Resources for quality control
When the SQA mandate includes configuration control activities, the required
resources will also include those required for configuration control. Merging SQA
and configuration control is not uncommon, and can eliminate some duplication
of assignments and activities. Two alternative organizational charts are shown in
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Fig. 8.5. Note that for small projects, merging the two groups may mean simply
assigning both responsibilities to the same person.
Though many tools are common to quality control and configuration control, few
tools are specifically designed for quality control. The following are some of the
general support tools that can be useful in supporting SQA activities:
·
Documentation utilities
·
Software design tools
·
Debugging aids
·
Structured preprocessors
·
File comparators
·
Structure analyzers
·
Standards auditors
·
Simulators
·
Execution analyzers
·
Performance monitors
·
Statistical analysis packages
·
Integrated CASE tools
·
Test drivers
·
Test case generators
These tools support quality control in all phases of software development.
Documentation aids can provide partially automatic document writers, spelling
checkers and thesauruses etc. Structured preprocessors (such as the UNIX utility
lint) are useful both to standardize code listings. And to provide additional
compile-time warnings that compilers often overlook. Early warnings regarding
possible execution time problems can be provided by simulators, execution time
analyzers and performance monitors. Substantial software system testing can
often be performed automatically by test suite generators and automatic test
executors.
All SQA tools to be used during software development should be identified and
described in the SQA plan. This plan includes a description of all required quality
assurance resources and details of how they will be applied. Thus, at the start of
the project SQA resources can be budgeted and procured as part of the required
project development resources.
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(a)
Project manager
Configuration
Software quality
control
control
CC manage
OC manager
(b)
Project manager
Software quality
assurance SQA
Configuration
Software quality
control
control
10.6
Quality Assurance
Quality assurance consists of the auditing and reporting functions of
management. The goal of quality assurance is to provide management with the
data necessary to I be informed about product quality, thereby gaining insight and
confidence that product quality is meeting its goals. Of course, if the data
provided through quality assurance identify problems, it is management's
responsibility to address the problems, and apply the necessary resources to
resolve quality issues.
Software Quality Assurance
Even the most jaded software developers will agree that high-quality software is
an important goal. But how do we define quality? A wag once said, 'Every
program does something right, it just may not be the thing that we want it to do.'
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Many definitions of software quality have been proposed in the literature. For our
purposes, software quality is defined as:
Conformance to explicitly stated functional and performance requirements,
explicitly documented development standards, and implicit characteristics that
are expected of all professionally developed software.
There is little question that this definition could be modified or extended. In fact,
a definitive definition of software quality could be debated endlessly. For the
purposes of this book, the definition serves to emphasize three important points:
1. Software requirements are the foundation from which quality is measured.
Lack of conformance to requirements is lack of quality.
2. Specified standards define a set of development criteria that guide the manner
in which software is engineered. If the criteria are not followed, lack of
quality will almost surely result.
3. A set of implicit requirements often goes unmentioned (e.g., the desire for
ease of use and good maintainability). If software conforms to its explicit
requirements but fails to meet implicit requirements, software quality is
suspect.
Background Issues
Quality assurance is an essential activity for any business that produces products
to be used by others. Prior to the twentieth century, quality assurance was the sole
responsibility of the craftsperson who built a product. The first formal quality
assurance and control function was introduced at Bell Labs in 1916 and spread
rapidly throughout the manufacturing world. During the 1940s, more formal
approaches to quality control were suggested. These relied on measurement and
continuous process improvement as key elements of quality management.
Today, every company has mechanisms to ensure quality in its products. In fact,
explicit statements of a company's concern for quality have become a marketing
ploy during the past few decades.
The history of quality assurance in software development parallels the history of
quality in hardware manufacturing. During the early days of computing (1950s
and 1960s), quality was the sole responsibility of the programmer. Standards for
quality assurance for software were introduced in military contract software
development during the 1970s and have spread rapidly into software development
in the commercial world [IEE94].
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Extending the definition presented earlier, software quality assurance is a planned
and systematic pattern of actions [SCH98] that are required to ensure high quality
in software.
The scope of quality assurance responsibility might best be characterized by
paraphrasing a once-popular automobile commercial:
Quality is Job # 1'. The implication for software is that many different
constituencies have software quality assurance responsibility-software engineers,
project managers, customers, salespeople, and the individuals who serve within an
SQA group.
The SQA group serves as the customer's in-house representative. That is, the
people who perform SQA must look at the software from the customer's point of
view. Has software development been conducted according to pre-established
standards? Have the technical disciplines properly performed their roles as part of
the SQA activity? The SQA group attempts to answer these and other questions to
ensure that software quality is maintained.
SQA Activities
Software quality assurance is composed of a variety of tasks associated with two
different constituencies-the software engineers who do technical work and an
SQA group that has responsibility for quality assurance planning, oversight,
record keeping, analysis, and reporting. 'If Software engineers address quality and
perform quality assurance and quality control activities by applying solid
technical methods and measures, conducting formal technical reviews, and
performing well-planned software testing.
The charter of the SQA group is to assist the software team in achieving a high-
quality end product. The Software Engineering Institute [PAU93] recommends a
set of SQA activities that address quality assurance planning, oversight, record
keeping, analysis, and reporting.
These activities are performed (or facilitated) by an independent SQA group that:
1. Prepares SQA plan for a project
The plan is developed during project planning and is reviewed by all
interested parties. Quality assurance activities performed by the software
engineering team and the SQA group are governed by the plan. The plan
identifies
·
evaluations to be performed
·
audits and reviews to be performed
·
standards that are applicable to the project
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Software Project Management (CS615)
·
procedures for error reporting and tracking
·
documents to be produced by the SQA group
·
amount of feedback provided to the software project team
2. Participates in the development of the project's software process
description
The software team selects a process for the work to be performed. The SQA
group reviews the process description for compliance with organizational
policy, internal software standards, externally imposed standards (e.g., ISO-
900 I), and other parts of the software project plan.
3. Reviews software engineering activities to verify compliance with the
defined software process. The SQA group identifies, documents, and tracks
deviations from the process and verifies that corrections have been made.
4. Audits designated software work products to verify compliance with
those defined as part of the software process. The SQA group reviews
selected work products; identifies, documents, and tracks deviations; verifies
that corrections have been made; and periodically reports the results of its
work to the project manager.
5. Ensures that deviations in software work and work products are
documented and handled according to a documented procedure.
Deviations may be encountered in the project plan, process description, -
applicable standards, or technical work products.
6. Records any noncompliance and reports to senior management.
Noncompliance items are tracked until they are resolved.
In addition to these activities, the SQA group coordinates the control and
management of change and helps to collect and analyze software metrics.
10.7
SQA Plan
The SQA plan serves as the template for SQA activities planned for each software
project. The SQA group and the project team develop the SQA plan. The initial
two sections of the plan describe the purpose and references of the SQA plan. The
next section records details of the roles and responsibilities for maintaining
software product quality.
The Documentation section of the SQA plan describes each of the work products
produced during the software process. This section defines the minimum set of
work products that are acceptable to achieve high quality. The Documentation
section consists of:
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­ Project document such as project plan, requirements document, test cases, test
reports, user manual, and administrative manuals
­ Models such as ERDs, class hierarchies
­ Technical document such as specifications, test plans
­ User document such as help files
All applicable standards to be used in the project are listed in the Standards and
Guidelines section of the SQA plan. The standards and practices applied are the
document standards, coding standards, and review guidelines.
Example of the contents of a software quality assurance plan
1. Software quality assurance organization and resources
Organization structure.
Personnel skill level and qualifications
Resources
2. SQA standards, procedures, policies and guidelines
3. SQA documentation requirements
List of all documentation subject to quality control
Description of method of evaluation and approval
4. SQA software requirements
Evaluation and approval of software
Description of method of evaluation
Evaluation of the software development process
Evaluation of reused software
Evaluation of non-deliverable software
5. Evaluation of storage, handling and delivery
Project documents
Software
Data files
6. Reviews and audits
7. Software configuration management (when not addressed in
a separate document)
8. Problem reporting and corrective action
9. Evaluation of test procedures
10. Tools techniques and methodologies
11. Quality control of subcontractors, vendors and suppliers
12. Additional control
Miscellaneous control procedures
Project specific control
13. SQA reporting, records and documentation.
Status reporting procedures
Maintenance
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Storage and security
Retention period
10.8
Software quality metrics
Much attention has been devoted to questions associated with the measurement of
quality. How do we determine the extent to which a software product contains this
vague attribute called quality? When is the quality of a software product high and
when is it low?
One of the more recent developments in quality assurance (not only for software)
is the realization that quality is not a binary attribute that either exists or does not
exist. Kaposi and Myers (1990), in a paper on measurement-based quality
assurance, have stated their belief that 'the quality assurance of products and
processes of software engineering must be based on measurement 7. The earlier
the measurement of quality begins, the earlier problems will be located. Cohen et
al. (1986), in addressing the cost of removing errors during the early phases of
software development, proclaim the existence of the famous exponential law8.
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The quality of two products can be compared, and it is perfectly acceptable to
claim that the quality of one product is greater than the quality of another. It is
also acceptable to measure quality and deduce the extent of expected faults based
on the measured result.
The set of measurable values associated with the quality of a product is referred to
as the product's quality metrics. Software quality metrics can be used to determine
the extent to which a software product meets its requirements. The use of quality
metrics increases the objectivity of the evaluation of product quality. Human
evaluation of quality is subjective, and is therefore a possible source of
disagreement, particularly between customer and developer.
A number of methods for establishing software quality metrics are currently being
developed, though no generally accepted standard has yet emerged. For example,
an initial draft of IEEE Std-1061 (1990) includes a detailed discussion of software
quality metrics in general, including a suggested methodology for applying
metrics, and many examples and guidelines. Quality metrics, once defined, do
indeed increase objectivity, but the definition itself is not necessarily objective
and greatly depends upon the needs of the organization that produces the
definition.
The basic approach for applying software quality metrics requires:
·
The identification of all required software quality attributes. This is usually
derived from the software requirements specification.
·
Determinations of measurable values to be associated with each quality
attribute. A description of the method by which each measurable value will be
measured.
·
A procedure for documenting the results of measuring the quality of the
software product.
A set of many values can be used to determine the overall quality of a software
product. However, a single measure can be created to represent the overall quality
of the software product. This requires:
·
A weighted method for combining the measured quality attributes into a
single measure of quality for the product.
Some examples of software metrics are:
Reliability: The percentage of time that the system is successfully operational
(e.g. 23 out of 24 hours produces: 100 x (23/24) percent)
Recoverability: The amount of time it takes for the system to recover after failure
(e.g. 1hour to reload from backups and 30 minutes to reinitialize the system)
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User-friendliness: The amount of training time needed for a new user
The measurement of software quality should not be performed only at the end of a
project. The degree of quality should be measured at regular intervals during
development. Thus, any major reduction in the overall measure of quality should
act as a warning for the project manager that collective action is required. High
quality at the end of the project is achieved by assuring high quality throughout
the development of the project.
10.9
Some general guidelines
The basic software quality assurance activities cover the review and approval of
the development methodology, the software and documentation, and the
supervision and approval of testing. Other SQA activities, such as the supervision
of reviews, the selection and approval of development tools, or the administration
of configuration control, depend on the way SQA is adapted to a specific project.
The size of the project is usually the determining factor. The following guidelines
discuss some of the parameters to be considered for different types of project
when planning SQA.
·
In small projects, many SQA activities can be performed by the project
manager. This includes the organization and supervision of reviews and
audits, the evaluation and selection of development tools, and the selection
and application of standards.
·
Test procedures and testing are always best when conducted by a separate
independent team (discussed later). The decision on whether supervision of
testing activities can be assigned to SQA depends on many factors, including
the independence of the SQA team, the size of the project and the 'complexity
of the project.
·
When testing is performed by an independent test team, SQAS involvement
will be minimal. In most other cases it will be the responsibility of the SQA
team to plan and supervise the testing of the system.
·
As a general guideline, it is usually undesirable for SQA to be performed by a
member of the development team. However, small projects often cannot
justify the cost of a dedicated SQA engineer. This problem can be solved by
having a single SQA engineer responsible for two or three small projects (with
each project funding its share of the SQA services).
One additional guideline is based on the conclusions of Wesselius and Ververs
(1990) for the application of effective quality control:
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Software Project Management (CS615)
·
The ability to control software quality is directly linked to the quality of the
software requirements specification. Quality control requires the unambiguous
specification of as many of the required characteristics of the software product
as possible.
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Table of Contents:
  1. Introduction & Fundamentals
  2. Goals of Project management
  3. Project Dimensions, Software Development Lifecycle
  4. Cost Management, Project vs. Program Management, Project Success
  5. Project Management’s nine Knowledge Areas
  6. Team leader, Project Organization, Organizational structure
  7. Project Execution Fundamentals Tracking
  8. Organizational Issues and Project Management
  9. Managing Processes: Project Plan, Managing Quality, Project Execution, Project Initiation
  10. Project Execution: Product Implementation, Project Closedown
  11. Problems in Software Projects, Process- related Problems
  12. Product-related Problems, Technology-related problems
  13. Requirements Management, Requirements analysis
  14. Requirements Elicitation for Software
  15. The Software Requirements Specification
  16. Attributes of Software Design, Key Features of Design
  17. Software Configuration Management Vs Software Maintenance
  18. Quality Assurance Management, Quality Factors
  19. Software Quality Assurance Activities
  20. Software Process, PM Process Groups, Links, PM Phase interactions
  21. Initiating Process: Inputs, Outputs, Tools and Techniques
  22. Planning Process Tasks, Executing Process Tasks, Controlling Process Tasks
  23. Project Planning Objectives, Primary Planning Steps
  24. Tools and Techniques for SDP, Outputs from SDP, SDP Execution
  25. PLANNING: Elements of SDP
  26. Life cycle Models: Spiral Model, Statement of Requirement, Data Item Descriptions
  27. Organizational Systems
  28. ORGANIZATIONAL PLANNING, Organizational Management Tools
  29. Estimation - Concepts
  30. Decomposition Techniques, Estimation – Tools
  31. Estimation – Tools
  32. Work Breakdown Structure
  33. WBS- A Mandatory Management Tool
  34. Characteristics of a High-Quality WBS
  35. Work Breakdown Structure (WBS)
  36. WBS- Major Steps, WBS Implementation, high level WBS tasks
  37. Schedule: Scheduling Fundamentals
  38. Scheduling Tools: GANTT CHARTS, PERT, CPM
  39. Risk and Change Management: Risk Management Concepts
  40. Risk & Change Management Concepts
  41. Risk Management Process
  42. Quality Concept, Producing quality software, Quality Control
  43. Managing Tasks in Microsoft Project 2000
  44. Commissioning & Migration