1. Introduction
In this tutorial, we’ll discuss the topic of software quality and how to ensure that our products are of high quality. Additionally, we’ll cover an example of international standards concerned with improving the quality of software products.
2. What Is Software Quality?
Software quality measures how well a software product performs its intended functions. It can be qualitative (based on subjective assessments) or quantitative (based on numerical measures).
Overall, quality attributes describe the characteristics of a software product that make it better or worse than other products. Therefore, quality software meets the end user’s needs while being reliable, well-supported, maintainable, portable, bug or defect-free, and easily integrable with other tools.
Software quality is essential for both security and usability. With high-quality software, business processes are more predictable and ensure that their results are reliable and credible. Additionally, customers will be more satisfied and likely to trust a company’s services if its software is of high quality.
3. Key Aspects of Software Quality
Software quality can be challenging to determine, but there are various ways to measure it.
To measure the quality of software development, we keep track of various parameters (quality attributes). They estimate the performance of a software product during its development and after its release. This information can help us ensure the software development process’s quality and ensure it’s running smoothly.
The attributes for estimating software quality include correctness, reliability, usability, understandability, modifiability, efficiency, testability, and portability.
3.1. Correctness
Software products must perform their specified tasks exactly as required. It’s vital for software to meet this requirement since erroneous behavior causes problems for users.
If the software meets its specification and does only what’s in there, we consider it correct. Otherwise, it contains bugs or behaves in an undocumented way.
3.2. Reliability
The reliability of a product is determined by how it performs under different working conditions and in different environments.
If a product is reliable, it should work correctly under all conditions.
3.3. Usability
The usability of software is essential for two reasons. First, the user should be able to use the software easily and without problems.
Second, the user should be able to access common functionalities without configuring anything or getting help.
3.4. Understandability
The code must be easy to understand and well-organized. It should behave the way a developer would expect. Anything in the code that causes confusion reveals that the code is not well written.
High-quality code always appears logical and easy to understand.
3.5. Maintainability
For a piece of software to be maintainable, we should be able to change its code when necessary. This achieves flexibility and allows the software to be adapted to changes in its use cases.
Coding a software system around a specific functionality without planning for possible changes in the future can make it difficult to adjust later. This can lead to problems down the road.
3.6. Efficiency
Efficient software uses as few physical resources as possible and achieves as much as possible with the least resources.
Software that is efficient and fast is also memory-efficient and CPU-friendly. As a result, it’s also battery-friendly and uses few external services.
3.7. Testability
Verification is important to ensure that the software is functioning as intended. Testing it should be easy so that every possible use case can be covered.
In addition, verification metrics should be readily available so developers can track their progress.
3.8. Portability
Portable software is versatile and usable in different settings, and we can reuse it across projects.
Using the same software product in various contexts and settings has two benefits. First, it speeds up the development of other products and services which use it. Second, it enlarges its market share and customer base.
4. McCall’s Quality Models
Software quality models are widely used to help manage the quality of software systems.
A software quality model is a formalized way of measuring how well a software product meets specific standards. As the software industry grows, more products are being created daily, so it’s essential to know that the product we’re buying (or developing) meets certain expectations.
4.1. McCall’s Quality Model
McCall’s model is a collaborative approach to getting the best results from users and developers. It involves working together to produce high-quality software:
This model lists three perspectives of quality in software: product revision, product transition, and product operations. Each perspective has its own set of quality attributes that are important to consider.
4.2. Product Revision
Product revision is a change or enhancement to a software product that helps meet the end user’s needs and requirements.
Quality factors that may affect a product revision include:
- Maintainability
- Flexibility
- Testability
4.3. Product Transition
Product transition refers to adapting a software product to new conditions or environments.
We do this by identifying a quality factor that indicates the software needs to change in response to new surroundings:
- Portability
- Re-usability
- Interoperability
Interoperability is the ability of a software system or part of the system to work with other systems and/or parts of those systems.
4.4. Product Operations
This perspective deals with the degree to which software meets user expectations and runs smoothly without defects. It covers the following metrics:
- Correctness
- Reliability
- Efficiency
- Usability
5. How to Develop Quality Software?
Quality is essential in all projects, but some aspects can be more critical than others. For example, reliability, usability, and understandability should be the main priorities in some cases. In other instances, testability and efficiency should be the primary concerns.
For instance, aircraft software must be reliable since not responding to users’ actions exactly as specified may have fatal consequences. In this case, metrics such as interoperability and portability aren’t as important as reliability.
So, there is no universal way to prioritize quality aspects in software engineering, as the priorities depend on the particular project.
Nevertheless, as software engineers, we must know which quality aspects are the most important to our project and focus on those areas to achieve the best possible results.
6. Conclusion
In this article, we discussed the concept of software quality, which is crucial to successful software development.
To produce a quality product, we must first understand the metrics defining it. Then, we should set standards for each quality metric to ensure the product meets customer expectations.
This means we should conduct quality control. When we find problems with quality, we need to make proper improvements.