Software Quality Models Overview

Today, there is increasing attention to technological development. Thanks to its capacity for wealth creation, scientist continues to turn out new inventions every year. Prime among this advancement is the emergence of new software.

However, with its increased development, it has become expedient to ensure that these new applications meet a minimum standard. That is, the portability, integrity, and usability, of the software, satisfy the need of a user. It is in this light that various models have emerged to measure the quality of software. Noteworthy, these models are called Software Quality Models.

In view of this, this essay provides an overview of the concept. Noteworthy, this essay on software quality models overview delineates the various existing models.

A quality model is a “set of characteristics and the relationship between them that provides the basis for specifying quality requirements and evaluation.” Also, the quality of a software product refers to the extent to which a component, process, or system satisfies a specified requirement or expectations and needs of end-users. (Miguel et al., 2014)

Hence, software quality models are models that enable the measurement of the quality of a software product. Precisely, these models function to measure whether a particular software adequately satisfies the existing requirements and identified the needs of an end-user. (Miguel et al., 2014)

Existing Software Quality Models

Various models have emerged to standardize software quality. Noteworthy, these models fall under two categories, namely the “Basic Models” and the “Tailored Quality Models.” (Miguel et al., 2014)

The Basic Models

This category began with the Mc Call Model of 1977 and spanned till 2001. It involves a total and comprehensive evaluation of a software product in order to determine its quality. These models are structurally hierarchical and are adaptable to various types of software products for their evaluation and, in turn, improvement. Noteworthy, there are five prominent models under this category. (Miguel et al., 2014)

1. Mc Call’s Model

Mc Call and his colleagues developed this model in 1977. This model established the quality of a product through various features, which can then be categorized under three perspectives. (Miguel et al., 2014)

The first perspective is a product review and involves functions such as maintenance, testing, and flexibility. The second perspective is product operation, which involves whether a product is correct, efficient, reliable, and usable. Finally, the third perspective is product transition, which considers the reusability, interoperability, and portability of a selected product. (Miguel et al., 2014)

Noteworthy, the significant contribution of this model was to examine the relationship between metrics and quality characteristics. It also constituted the basis of further models. On the other hand, a significant limitation of this model is its accuracy as it used a Yes or No response. (Miguel et al., 2014)

2. Boehm Model

Boehm and his colleagues pioneered this model in 1978, and it mainly improved on the Mc Call model. This model establishes wide-scale features and included factors at various levels. Noteworthy, these factors are utility, maintainability, and portability. (Miguel et al., 2014)

Utility indicates the easiness, efficiency, and reliability in the use of a software product. Maintainability describes the capacity to modify the segments of understanding and testability. Portability then describes the capacity for continuous usage even after a change in the environment. (Miguel et al., 2014)

3. FURPS Model

This model emerged in 1992, and it categorizes the features of a product as either Functional Requirements (RF) or Non-Functional (NF). In the former’s case, this model defines the expected inputs and outputs by its Functionality (F). In the latter’s case, this model groups the features under Reliability (R), Performance (P), Product Support (S), and Usability (U). However, it fails to consider some main features like portability. (Miguel et al., 2014)

4. Dromey Model

This model emerged in 1995, and it exists within the context of product quality. This model identifies a more dynamic and different process of evaluation for every product. It posits that a satisfactory product is one wherein all its elements satisfy the necessary quality. These qualities include functionality, reliability, efficiency, maintainability, portability, and reusability. (Miguel et al., 2014)

5. ISO 9126 Model

This model emerged in 2001 and it is based on the Boehm and Mc Call model. It has two significant parts, firstly of the characteristics of external and internal quality, and secondly of the quality in the use of the product. (Miguel et al., 2014)

Generally, internal qualities are those system properties that can be assessed without executing, while external qualities are assessable through observation during execution. On the other hand, quality in use concerns the software product’s effectiveness, security, and productivity for the benefit of the user. (Miguel et al., 2014)

The Tailored Quality Models

This category involves models that emerged from 2001 to date. It began with the Bertoa Model and concerned itself with the evaluation and examination of the components of a software package. They were developed from the Basic Models and focused on a specific domain of application. They also focused on the utilization of Commercial Off-The-Shelf Components (COTS). (Miguel et al., 2014)

There are various models under this category, namely, the Generic, Multilayered and Customizable Model, Alvaro Model, Bertoa Model, and the Rawashdeh Model. The significant models under this category are examined below.

1. Bertoa Model

This model was developed from the ISO 9126 Model and delineated a set of attributes for the adequate evaluation of COTS. This model then categorizes quality under characteristics, then further delineate them into sub-characteristics (Runtime) and sub-characteristics (Life cycle). For instance, functionality is delineated into accuracy under runtime and suitability under the life cycle. (Miguel et al., 2014)

2. Rawashdeh Model

This model emerged from the Dromey and ISO 9126 model. Accordingly, this model stipulates four steps to establish a product quality standard. These processes involve identifying a group of essential quality features then delineating them into subordinate attributes.

Afterward, differentiate between external and internal metrics. Then, identify the users for each attribute. Finally, build a novel model using the ideas of the Dromey and ISO 9126 Model.

This essay on software quality models overview has examined the two major categories of software quality models. However, there exists a third category that has emerged in recent times – Free Software Orientated Models. Noteworthy, like the Tailored Quality Models, they also developed premised on the Basic Models. However, they focus on the quality of free or open-source software.