Quality Assurance Management, Quality Factors

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Software Quality Assurance Activities >>

Software Project Management (CS615)

LECTURE # 18

2. Software Development Fundamentals

Technical Fundamentals

2.15

Quality Assurance Management

⇒ Definition

According to American Heritage Dictionary, quality is defined as "an inherent or

distinguishing characteristic or a property".

The distinguishing characteristics of a software product are the cyclomatic

complexity, cohesion, function points, and lines of code. These characteristics of

a software product define the quality of the product.

The US DOD (1988) defines software quality rather simply as:

The ability of a software product to satisfy its specified requirements.

The British Standards Institution (1986) has stated that:

"Quality is in the eye of the beholder, a matter, of the client's judgment."

⇒ Quality Standards and Procedures

The quality of software is said to be high if it meets the standards and procedures,

defined for the product. Standards are criteria to which the products are compared.

For example, there may be standards that govern the quality review process.

Documentation standard design standard and code standard are the three types of

standards that software projects usually follow.

Documentation standard specifies the form and content for planning, control, and

product documentation. Design standards provide rules and methods for

translating the software requirements into software design. The design standards

are specified in the form and content of the product design.

Unlike documentation standard, code standard defines the language in which code

should be written. The standard clearly mentions the structures, style conventions,

and rules for data structures and interfaces that will be implemented in the project.

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Procedures are criteria to which the development and control processes are

compared. Procedures are explicit steps followed in a process. Procedures need to

be properly documented because they are needed for configuration management,

nonconformance reporting, corrective action, testing, and formal inspections.

Proper documentation of procedures is necessary because SQA activities rely on

them for project compliance. Organizations normally enforce quality standards

with the help of checklists, common error lists, and standards and guidelines.

⇒ Concepts

Product quality depends on its conformance to software requirements,

development standards, and implicit requirements.

During software development, the quality of a product depends on the quality of

the design.

The quality of product design, in turn, depends on how effectively the product

designer captures the client requirements and specifications. At times, the client

has some implicit requirements that are not captured in the requirements

document. There are three things that guide requirements: want, desire, and wish.

Usually, wants are captured explicitly in the requirements documents. However, if

you manage to capture desires and wishes, the product becomes a great success.

The product designer needs to state these implicit requirements clearly during

analysis. The adherence to these implicit requirements is the key attribute that sets

one product apart from another.

The product quality also depends on how strictly, and to what degree the

developer adheres to design specifications. This is what the concept quality is

meeting or exceeding our client's needs and requirements' means.

The product quality is said to be high if the product is manufactured according to

design specifications.

⇒ Quality Control

Quality control is a series of review activities, such as:

Inspections

Reviews and

Tests, used throughout the SDLC of the software product

The objective of quality control is to find problems as early as possible and fix

them.

Quality control ensures that the software product meets the requirements defined

at every stage in its development.

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There is provision for feedback mechanism during quality control. Any slippage

in meeting the requirements during the development process is communicated to

the development team immediately.

Feedback ensures that errors or misses found during quality control are rectified

as soon as they are detected.

During software development, quality control plays a valuable role by evaluating

products against standards and specifications.

Quality control activities can be fully automated manual, or a combination of

these. Quality control involves monitoring specific project results to determine if:

They comply with relevant quality standards

Identifying ways to eliminate causes of unsatisfactory results.

Project results include both:

Product results, such as deliverables, and

Project management results, such as cost and schedule performance.

⇒ Quality Factors

There are a number of factors that determine the quality of a software product.

These factors can be measured either directly or indirectly. McCall (MCC77) and

his colleagues proposed some software quality factors based on three most

important aspects of a software product:

1. Product operation

2. Product revision and

3. Product transition

1. Product Operation Factors

The product operation factors determine the quality of software when a

program is executed. Good quality software is not only correct and reliable

but also delivers correct performance in all circumstances. Some of the factors

of product operation are correctness, reliability, efficiency, integrity, and

usability. You can look at the factor description in Table 1.

Table 1: Product Operation Factors

Accuracy of the program and the extent to which it fulfills design specifications

Correctness

Extent to which the program is secure and its ability to recover quickly from failure.

Reliability

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Software Project Management (CS615)

Performance of the program and its ability to perform tasks within a time frame

Efficiency

Ability of the program to take care of security and the extent to which it can prevent

Integrity

unauthorized.

Ease with which a user can learn, operates, and uses the program.

Usability

2. Product Revision Factors

Product revision factors focus on the ease of maintenance of the software

product. Maintenance tasks could be either correcting faults in the original

design or making improvements to adapt the functionality to changing

environments. Product revision covers the following factors: maintainability,

flexibility, and testability. These factors are described in Table 2.

Table 2: Product Revision Factors

Maintainability Ease with which a program is debugged.

Ease with which a program is modified.

Flexibility

Ease with which a program is tested.

Testability

3. Product Transition Factors

The product transition factors determine the quality of programs that are

designed for open systems. Here the focus is more on the portability and

reusability of a software product. To help a system run on different platforms,

certain parts of a system may be reused. The product transition factors are

portability, reusability, interoperability, configurability, and expandability.

These factors are described in Table 3.

Table 3: Product Transition Factors

Efficiency with which a program runs on different platforms or operating systems

Portability

Extent to which the program can be used in more than one program or system

Reusability

Interoperability Effort needed to transfer a program to another system

Ability of the program to be installed at more than one location with different

Configurability

features at each location

Ability of the program to support an increase in data and users

Expandability

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