With the abundance of web applications, it is becoming increasingly essential to fill applications not with countless, but with relevant features and to deliver good usability. According to the rule of seven (plus or minus two), a person can process or store seven (plus or minus 2) units of information in his memory at the same time. Due to other negative factors (such as noise or fatigue), this number may be even lower (Miller, 1956).
Software in which usability aspects are considered and incorporated increases the chance that users will continue to use this software and not look for alternatives. Applications are primarily developed for non-tech-savvy users, and often the focus is more on the technological aspects and less on the human-machine interaction (Krug, Bayle, Straiger & Matcho, 2014).
A definition that can be found again and again in the literature, whether in Krug et al., Nielsen, or in various ISO standards, is that usability is defined by the fact that users can effectively, efficiently, and satisfactorily complete specific tasks in a specific context with the system, the product, or the service without having to invest more effort in completing the task than it brings benefits (ISO 25022, 2016; ISO 26513, 2017; Krug et al., 2014; Nielsen, 2005).
The following table shows 10 widely established usability heuristics established by Nielsen in 1994 and updated in 2020 (Nielsen, 2005).
| Heuristics | Description |
|---|---|
| Visibility of system status | The design should always keep users informed about what is going on, through appropriate feedback within a reasonable amount of time. |
| Match between system and the real world | The design should speak the users’ language. Use words, phrases, and concepts familiar to the user, rather than internal jargon. Follow real-world conventions, making information appear in a natural and logical order. |
| User control and freedom | Users often perform actions by mistake. They need a clearly marked “emergency exit” to leave the unwanted action without having to go through an extended process. |
| Consistency and standards | Users should not have to wonder whether different words, situations, or actions mean the same thing. Follow platform and industry conventions. |
| Error prevention | Good error messages are important, but the best designs carefully prevent problems from occurring in the first place. Either eliminate error-prone conditions, or check for them and present users with a confirmation option before they commit to the action. |
| Recognition rather than recall | Minimize the user’s memory load by making elements, actions, and options visible. The user should not have to remember information from one part of the interface to another. Information required to use the design (e.g. field labels or menu items) should be visible or easily retrievable when needed. |
| Flexibility and efficiency of use | Shortcuts — hidden from novice users — may speed up the interaction for the expert user so that the design can cater to both inexperienced and experienced users. Allow users to tailor frequent actions. |
| Aesthetic and minimalist design | Interfaces should not contain information that is irrelevant or rarely needed. Every extra unit of information in an interface competes with the relevant units of information and diminishes their relative visibility. |
| Help users recognize, diagnose, and recover from errors | Error messages should be expressed in plain language (no error codes), precisely indicate the problem, and constructively suggest a solution. |
| Help and documentation | It’s best if the system doesn’t need any additional explanation. However, it may be necessary to provide documentation to help users understand how to complete their tasks. |
The following table shows usability aspects Krug mentions in his book Dont make me think (Krug 2014).
| Aspects | Description |
|---|---|
| Useful | Does it do something people need done? |
| Learnable | Can people figure out how to use it? |
| Memorable | Do they have to relearn it each time they use it? |
| Effective | Does it get the job done? |
| Efficient | Does it do it with a reasonable amount of time and effort? |
| Desirable | Do people want it? |
| Delightful | Is using it enjoyable, or even fun? |
Usability aspects defined in ISO 25010 are described in the following table (ISO25010, 2011).
| Aspects | Description |
|---|---|
| Effectiveness | How effective does the user need to be when using the system to perform their task? |
| Efficiency | How efficient does the user need to be when using the system to perform their task? |
| Satisfaction | How satisfied does the user need to be when using the system to perform their task? |
| Freedom from risk | How risk free does using the system to perform their task need to be for the user? |
| Reliability | How reliable does the system need to be when the user uses it to perform their task? |
| Security | How secure does the system need to be when the user uses it to perform their task? |
| Context coverage | To what extent does the system need to be effective, efficient, risk free and satisfying in all the intended and potential contexts of use? |
| Learnability | To what extent does learning to use the system need to be effective, efficient, risk free and satisfying? |
| Accessibility | To what extent does the system need to be effective, efficient, risk free and satisfying to use for people with disabilities? |
Usability also aims to reduce cognitive load. The Cognitive Load Theory describes that the learning of complex cognitive tasks is made more difficult by the fact that the learner is overwhelmed with interactive information (van Gog, Paas & Sweller, 2010). Users usually have a goal they want to achieve when they use an application. This goal should be achieved as easily as possible without overloading the user with clutter.
According to Krug et al. (2014), it can be assumed that conducting usability evaluations at regular intervals with the involvement of potential future users will increase the potential of the application to be accepted and used. If usability is only evaluated by those who were involved in the creation of the application, it is more likely that primarily technical aspects are taken into account and that processes in the application typical for the developers are perceived as effective and efficient, although the standard user finds them bumpy in his or her daily work. This is also supported by Krug et al. (2014).
Krug et al. assumes that when working on a system as a developer, a tunnel vision can develop after a short time, which potential end users do not have. A study on the evaluation of usability by Peker, Kucukozer-Cavdar and Cagiltay (2016) with 20 participants conducted on university websites showed that the main problems of all websites were unsatisfactory navigation, insufficient design of menus and main pages overfilled with elements.
Usability includes that users experience a positive feeling when working with the application. From the literature review, it appears that usability in a application that is appropriate for the user and positive feelings can be achieved through a combination of at least the following three factors.
- Comply with standards, norms, heuristics and aspects
- Usability evaluation
- Questionnaire
In part, this procedure with the three factors mentioned is already described in more detail in ISO 9241-210 (2019) as follows:
- The design is based on an explicit understanding of users, tasks and environments.
- Users are involved throughout the design and development process
- Design is driven and refined through user-centered evaluation
- The process is iterative
- Design is focused on the overall user experience
- Design team includes multidisciplinary skills and perspectives
Standards have become established in the design of applications to which users have already become accustomed. For example, placing the navigation menu horizontally at the beginning of the application or vertically, left-aligned. Deviations from such standards can lead to confusion among users and increase the cognitive load (Nielsen, 2005). Nielsen (2005) lists consistency and standards as one of his 10 usability heuristics. This describes exactly the point mentioned, that established standards should be adhered to in order to make it as easy as possible for users to get started with the application.
The aforementioned study on usability evaluation conducted by Peker et al. (2016) found that almost half of all participants described the navigation of applications as weak, which made it difficult to perform the tasks for evaluating the application. In order to reduce the cognitive load, reference can be made to, among others, the heuristic Recognize instead of Remember according to Nielsen (2005) and the aspect Learnable according to Krug et al. (2014). The simpler a application is designed, whereby simple can be translated here as not overloaded, the faster the user finds his way around the application and can learn to use it and achieve his intended goal.
Far too often, the mindset still prevails in companies and among developers that more functionality equals higher customer satisfaction. In reality, of the X functionalities or features offered in applications, only a subset Y is actually used by users (The Standish Group International, 2010). As a result, it can be assumed that applications should only offer subset Y as functionality, but this subset must be developed according to usability standards, norms, heuristics and aspects in order to increase customer satisfaction.
Special attention should be paid to the following 3 points, as they are congruent for usability across sources according to Krug et al. (2014), Nielsen (2005) and ISO 25010 (2011), among others.
| Aspects | Description |
|---|---|
| Simple | Simple in terms of the appearance of the web application or website. It must not be overloaded with information or elements that users consider to be unnecessary information or elements. |
| Consistent | Consistent with other applications in terms of standard elements such as navigation, menus, or links so that users can always expect to find a navigation at the beginning of the application, but also consistent in itself, so that the appearance of the application or website does not change drastically from link to link. |
| Clear | Clear in this context means that it must be clear to users how to use the application or website in order to achieve the goal the user has. |
Have you encountered any interesting usability challenges in your software projects? Or perhaps you have success stories to share about improving user experience through usability design? We’d love to hear from you! Leave a comment below and join the conversation. Your valuable insights and experiences could inspire and help others in our community of software enthusiasts. Together, let’s make software usability the foundation of exceptional user experiences!
For further information about Usability and how to evaluate it check out my Blog Enhancing UX: Exploring Software Usability Evaluation
Sources
Miller, G. A. (1956). The magical number seven, plus or minus two: Some limits on our capacity for processing information. doi: https://doi.org/10.1037/h0043158
Krug, S., Bayle, E., Straiger, A. & Matcho, M. (2014). Don’t make me think, revisited : a common sense approach to web usability. New Riders Press.
Nielsen, J. (2005). Ten usability heuristics. http://useit.com.
van Gog, T., Paas, F. & Sweller, J. (2010). Cognitive load theory: Advances in research on worked examples, animations, and cognitive load measurement (Bd. 22). doi: 10.1007/s10648-010-9145-4
ISO25010 – Systems and software engineering — Systems and software Quality Requirements and Evaluation (SQuaRE) — System and software quality models (Standard). (2011). International Organization for Standardization.
Peker, S., Kucukozer-Cavdar, S. & Cagiltay, K. (2016). Exploring the relationship between web presence and web usability for universities: A case study from turkey. Program, 50, 157-174. doi: 10.1108/PROG-04-2014-0024
The Standish Group International, I. (2010). Modernization clearing a pathway to success.
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