Quality Concepts

A. QUALITY.

Let we first of all define what do you mean by Quality?
As per the Rick Hover:
Quality involves entire Software Development PROCESS - monitoring and improving process, making sure that any agreed-upon standards and procedures are followed., and ensuring that problems are found and dealt with.
It means that quality refers to measurable characteristics. The characteristics of a software includes properties of the program such as cyclomatic complexity, cohesion, number of function point, lines of code and all other. We will have a look at these measures afterwards.
These characteristics leads us to two different categories of the quality.

1. Quality of Design :
It refers to the characteristics that designer specify.for a software. It includes tolerance and performance specification of a software. It encompasses requirements, specification and design of the system.

2. Quality of Conformance :
It is degree to which design specifications are followed during implementation of the software. If the implementation follows design and resulting system meets requirements and performance goals then conformance of quality is high.


B. QUALITY CONTROL:

It involves a series of inspections, reviews, and tests used throughout the software process.
It includes a feedback loop. Combination of measurement and feedback allows us to tune the process It can be automated, entirely manual or combination of both.
A key concept of quality control is that all products have defined, measurable specifications to which we may compare the output of each process.


C. QUALITY ASSURANCE:

It consist of auditing and reporting functions of management. The goal is to provide management with the data necessary to be informed about product quality. The measure concern is that the data provided by management should not have any problems. It's responsibility of the management to provide a proper data.


D. COST OF QUALITY:

It is done to provide a baseline for current cost of quality, identify opportunity for reducing cost and provide a normalized basis of comparison.
The quality cost can be divided mainly into 3 parts
1. Prevention Cost : It includes

• Quality Planning
• Format Technical Reviews
• Test Equipment
• Training

2. Appraisal Costs: Example of appraisal cost is

• in-process and interprocess inspection
• eqipment calibration and maintainance
• testing

3. Failure Cost: It can be subdivided into 2 parts.

a. Internal failure cost : occurs when we detect a defect in our product prior to shipment. It includes rework, repair etc.

b. External failure cost : occurs after product is delivered to customer. It can include product shipment, help line support and warranty work.