What is software quality?

The main problem in quality management is the fact that the definition of quality is too vague and ambiguous. This is due to the fact that usually the term quality misunderstood. Such confusion may be due to several reasons …

Try to answer the following questions:

• What is software quality?
• Popular opinion on the quality
• Professional approach to quality

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What is software quality?

In our first issue, we try to give a definition of quality and Software Qa.

The main problem in quality management is the fact that the definition of quality is too vague and ambiguous. This is due to the fact that usually the term quality misunderstood. Such confusion may be due to several reasons.

First, the quality is not a single idea or concept is more diverse and multidimensional concept.

Second, for any concepts and definitions, there are several levels of abstraction, for example, when people talk about as one of the means by this is too broad and vague sense, while another may refer to a specific definition and meaning.

Third, the term quality is an integral part of our everyday communication, but the common and professional use may be very different.

Popular opinion on the quality

Conventional wisdom about the quality is such that it is something intangible and intangible - of it may be controversy and debate, it is possible to criticize and praise, but to weigh and measure the quality of the impossible. Such expressions as "good quality" and "poor quality" are a clear example of how people talk about something uncertain for them, that they can not clearly describe and define. 

This opinion reflects the fact that people perceive and interpret quality in different ways. It is understood that quality can not be controlled and managed, and the more it can not be quantitatively measurable. Such a view clearly contrasts with the professional approach to quality management - quality is a well-defined quantity that can be measured and controlled, it can be managed and improved.

Other popular opinion that the quality is closely connected with a luxury first-class and refined taste. Dear, thoroughly thought out and more technically sophisticated product is considered as a guarantee of high quality than cheaper counterparts. Following this logic, Cadillac - is a quality car, and Chevrolet is not, despite the reliability and the number of breakdowns, or HI-FI system is a quality system, as an ordinary radio - no. Under this approach, the quality is limited to certain class of high-value products with sophisticated functionality and class products. Simply put, it is hardly inexpensive product will be classified as a quality product.

Professional approach to quality

Unfortunately, such an uncertain and vague ideas can not be used to improve functional testing services. Consequently, it is necessary to give a clear and easy to work definition. In 1979, Crosby has defined quality as "compliance» ("conformance to requirements"), and Juran and Gryna in 1970 to define quality as "fitness for use» ("fitness for use"). These two definitions are closely linked and are in excellent agreement, as we shall see later.

"Compliance" suggests that the requirements should be clearly defined so that they can not be understood and interpreted correctly. Later, at the design stage, made regular measurements of the developed product, to determine compliance. 

Any discrepancies should be considered a defect - the lack of quality. For example, the specification of a particular model of radio stations may require ability to make a certain frequency of radio waves at a distance of more than 30 kilometers from the source of broadcasting. 

If the station is unable to fulfill this requirement, it does not meet quality requirements and should be declared unfit and defective. Based on the same principles, if Cadillac meets all the requirements to machines Cadillac, then it’s a quality machine.

If Chevrolet meets all the requirements to machines Chevrolet, therefore, it is also a quality machine. These two machines can be quite different in style, speed and efficiency, but if both are measured by the standard sets for them, then they both will be high-quality machines.

The definition of "fitness for use" takes into account the requirements and expectations of end users of the product, which expect that the product or service provided will be convenient for their needs. However, different users can use the product differently, this means that the product must have the most diverse use cases. By definition, Juran each use case is a characteristic of quality and they can be classified into categories as parameters usability.

These two definitions of quality ("compliance" and "fitness for use") is essentially the same. The difference is that the version of "fitness for use" refers to the role requirements and expectations of the customer. The role of the customer associated with the quality, can never be overstated. From the perspective of the customer, product quality, which he acquired, consists of many different factors, such as: price, performance, reliability, etc.

Only your customer can tell you about the quality because it’s the only thing he really buys. The customer does not buy the product. He buys your assurance that all of his expectations for the product will be realized.

Conclusions

Let’s try again to give a definition of quality from the perspective of the customer or user of the product.

Quality - it’s suitability for use. Does the product is what I need, whether it makes my job if I can use it as I prefer.

And now look at the developer’s perspective.

Quality - is the compliance requirements specified and collected if the product does everything that is stated in the requirements.

The problem is that the specified requirements and collected is usually only part of the real requirements and expectations of the customer. Where is the correct definition of quality?

The quality of this correspondence is the real requirements, explicit and implicit. Very often implicit requirements are so obvious to the customer or the user that he does not even suggest that they are unknown to the developers. For example, let us return to our cars - the customer can describe in detail the requirements for the design parameters of the engine, interior design, exterior colors, but never point out that the tires should be round, and the windshield - transparent.

The customer will be satisfied only if the purchased product will fully meet its real and vital needs, as specified, or not.