Good Software quality attributes
Software quality is a fundamental aspect of any software development project. This article summarizes key attributes that refer to the characteristics or properties defining the software’s quality. These attributes can be further divided into functional and non-functional attributes, which collectively determine the software’s overall quality.
A well-crafted software package consists of the following attributes, each with its unique specifics:
- Usability
- Functionality
- Correctness
- Maintainability
- Reliability
- Flexibility
- Scalability
- Testability
- Efficiency
- Security
Among all the attributes, there is one that stands out: the software’s usability from a user experience perspective. Even if you have excelled in coding and considered all the other attributes mentioned earlier, poor intuitiveness and flow in the software can undermine everything.
Regardless of what perspective you look at the product, in the end, if it fails to meet the user’s expectations, it will be a failure. Therefore, having a vision for the best possible UX is of utmost importance.
Usability
In our perspective, usability is one of the most important attributes, as it plays a paramount role in a product’s success. After all, what is the point of spending effort on other attributes if the software fails at usability? Therefore, to achieve usability, one should embrace the KISS principle or “Keep it Simple Stupid.”
In other words, it refers to how effortlessly users can interact with the software to accomplish tasks and the number of clicks needed to reach the goal, or in the design’s native language,” to reach the tootsie.” Therefore a software application must have the following:
- Intuitive and user-friendly UI that is easy to understand and navigate
- Preferably requires minimum or even no previous training
- Minimum clicks required to complete a desired action, workflow, or process.
To excel in this attribute, having a skilled product owner with a clear vision is essential. Collecting user stories at the beginning, having a competent designer, and doing prototyping are equally vital. Additionally, considering users with different types of disabilities (such as color blindness, etc.) is also essential. Even though all software-driven systems are designed with ease of use in mind, not all manage to achieve it.
Functionality
The software’s functionality is its ability to perform the intended functions as specified in the requirements (such as User requirements, Software requirements, and Software design specifications). A good software application should include all the necessary features required for users to complete their tasks or workflows, as was intended in the product vision.
Equally important to functional requirements are non-functional requirements, which require efficient collaboration between the product owner and system architects to decide on which technologies to use and more. Thus, it falls upon the developers to ensure correct implementation based on the specifications, leading us to the next attribute, “correctness.”
Correctness
The name itself explains the key point of this attribute, signifying the system’s ability to perform tasks precisely as defined by its specification. One could say that this attribute is a necessary condition for a secure implementation, though insufficient. Therefore, if the program aligns perfectly with its specification, it is considered to be 100% correct. This also implies that the software either works entirely correctly or not at all, without any middle ground. It is considered an all-or-nothing attribute.
However, achieving 100% correctness is undoubtedly challenging.
Maintainability
Maintainability also represents one of the important attributes in software design, and it refers to how easily developers can modify (e.g., add new features in the future), extend, find a root cause in the code, and fix bugs in a software application. From a cost perspective, it indicates expenses involved in keeping the system running in the long term. Therefore, a maintainable software application must be well-structured, with clear and concise code that is easy to understand and modify. At the same time, it should enable changes to meet the users’ evolving needs.
This is where developers’ skills, vigilance, and discipline truly sets apart excellent developers from good ones. Why vigilance and ? For example, once the project is in the maintenance phase, one should be mindful of how to tackle post-release fixes. In this stage, considering available time, it becomes a balancing act of choosing when to do a thorough solution and when a “quick and dirty” solution is sufficient with a minimal impact on the code structure down the line. Meaning we will not end up with “unmaintainable spaghetti code” as developers like to say.
Reliability
Reliability is the software’s ability to perform the intended tasks consistently and without errors. At the same time, software should be able to handle all the possible errors and exceptions without crashing or losing data.
Flexibility
Flexibility can be considered as an individual attribute, but it can also include other related attributes such as Portability, Interoperability, Modularity, and Reusability. Each of these sub-attributes covers different aspects:
- Portability and/or Interoperability refers to the ability of a software application to run on different hardware and software platforms. An interoperable software application must be designed to be platform-independent and capable of running on various operating systems and hardware configurations. The most common challenges related to interoperability are the following:
- Supporting multiple data formats
- Supporting different APIs (e.g., User interface – UI or Operating systems – OS)
- Legacy systems (e.g., older OS versions)
- Lack of standards between different OS systems
- Modularity refers to designing the software with multiple separate individual components that can be modified, removed, or added without breaking the core software structure.
- Reusability is essential for software development in the long term. It can be viewed as the effort required to comprehend the systems and how cohesive it is. For example, how easy it is to reuse specific components on other projects, leading to faster project completion and enhanced robustness in the end.
Scalability
If taken into account, scalability can enable future improvements in the software without significant additional investments. By considering scalability vertically (more hardware resources for an existing server) or horizontally (distributed software design choices across multiple servers) during the software design process, developers can ensure that the software can grow and adapt to changing requirements. This also enables the software to handle increased workloads and deliver a reliable and responsive user experience.
Testability
In software development, it is crucial to perform numerous and extensive tests to ensure the final product meets expectations. So, what exactly is testability?
Testability indicates how effectively the application allows software testers to perform tests aligned with predefined test cases and criteria. It also assesses the ease with which QA engineers can develop test criteria for a dedicated system. However, testability is more than that. It also defines:
- How fast can a test for a specific feature be created?
- How much time is needed to perform System tests and Acceptance tests?
For instance, if the software testability level is low, it can result in a higher cost and greater difficulty in maintaining and updating the software in the future. Therefore, good practice in software development is for developers to prepare, (whenever possible or applicable) “Unit” and “Integration” tests during the project duration. These tests will ensure that the core architecture functions correctly before testers start to perform System and Acceptance tests.
Efficiency
Efficiency refers to the software’s performance, energy efficiency, speed and others. Definitely, no one prefers cumbersome and sluggish software. However, it is crucial to consider that even if the software appears efficient to users, it might still be inefficient as it could consume excessive resources, slowing down other applications or systems as a whole. Thus, software applications must be able to perform the intended tasks quickly and without excessive resource consumption. Careful consideration of which technology to use in each development project is essential.
A basic example would be if the software is designed for data processing. There are decisions to be made on how the data will be fetched and then processed. Will this happen in parallel or sequentially and how many resources would be required for each approach for example? Therefore, making sound decisions at the beginning of the project is paramount since poor choices could have a significant impact down the line.
Security
Last but certainly not least, we must include security in our list of the most important software quality attributes. Globally, the number of cyber-attacks has increased, and users have started prioritizing a product’s safety. Overall, software security is measured by the program’s ability to operate without endangering users, the software environment, and resources. The level of security in software varies based on its intended purpose. As a starting point, it is always wise to follow established best practices and recommendations for the technology used in software development.
Additionally, contributing to software security involves various aspects, such as selecting secure components to start with, conducting threat modelling, and implementing secure coding practices. From the user’s perspective, providing features like authorization and authentication (e.g., user login, two-factor authentication and other.) is also important. Lastly, software owners’ IT support should regularly perform system security checks to ensure they remain updated and well-protected. By considering all these measures, the software can attain a higher level of security, safeguarding users and their data.
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Summary
In the end, good software is a combination of multiple attributes that together form a comprehensive package. But regardless of how one perceives the software product, as stated above, the most important attribute is software usability, as it defines how the software will be accepted by the users. Without getting usability right, other attributes lose their significance.
