Information Technology Reference
In-Depth Information
12.2.2 McCall's Quality Factors
A more viable set of measures for software was developed by McCall, Richards
and Walters. Their measures relate directly to the field of software engineering.
Not all the quality factors they list can be directly measured; if indirect measures
of these are taken it is possible to assess the software quality. McCall's quality
factors are listed below with a brief explanation of each (McCall and Cavano
1978
).
• Correctness: The extent to which a program satisfies its specification and fulfills
the customer's mission objective.
• Reliability: The extent to which a program can be expected to perform its
intended function with required precision.
• Usability: The effort required to learn, operate, prepare input, and interpret
output of a program.
• Integrity: The extent to which access to software or data by unauthorized per-
sons can be controlled.
• Efficiency: The amount of computing resources and code required by a program
to perform its functions.
• Flexibility: The effort required to modify an operational program.
• Testability: The effort required to test a program to ensure that it performs its
intended functions.
• Maintainability: The effort required to locate and fix an error in a program.
• Portability: The effort required to transfer the program from one hardware and/
or software system environment to another.
• Reusability: The extent to which a program or parts of a program can be reused
in another application.
• Interoperability: The effort required to couple one system to another (Fig
12.1
).
Maintainability
Flexibility
Testability
Portability
Reusability
Interpolability
Product Revision
Product Transition
Product Operation
Correctness
Reliability
Usability
Integrity
Efficiency
Fig. 12.1
McCall's quality factor illustration (McCall and Cavano
1978
)
