Usability - convenience and ease of use - the ability of the digital product to be intuitively understood, studied and used. This includes attractiveness to the user under specified conditions (ISO / IEC 25010); the attribute of a system, product or service, in which a particular user can operate the system under certain conditions to achieve specified goals with the required efficiency and satisfaction (ISO 9241-210).
Usability in mobile and web software development is a result of the software design stage, which provides users with convenient facilities for app interaction, software or websites.
Good usability requires that:
- A website has a decent layout, is easy to navigate, consistent across all web pages, and useful and informative to visitors;
- An app should be bitsize and clear; content should be readable on different screen sizes, all the buttons and links are easy to use without rub contact. The intuitive design accompanies the features, while the main functions are obvious and easily available to users.
There are two main ways to assess the usability of the product:
- Direct evaluation based on the analysis of the efficiency and satisfaction achieved, as a result of product operation in real conditions: if in the above conditions one system is more ergonomic than the other, then the evaluation should detect this;
- Indirect evaluation based on the analysis of individual sub characteristics that reflect certain properties of the system in the specified operating conditions.
Direct evaluation is considered in the ISO 9241-11 standard, which assumes that the ergonomics of the system depends on all indicators affecting the operation of the system in real conditions, including both organizational indicators (for example, labor skills, location or appearance of products), and individual differences between users, for example, in the cultural level and preferences.
Indirect evaluation is considered in ISO / IEC 25010, which describes the following usability characteristics:
- Appropriateness recognizability: an ability of the user to understand whether the product or system is suitable for his or her needs, based on initial impressions, documentation and other information provided;
- Learnability: a degree of effectiveness, productivity and user satisfaction by learning how to use the system;
- Operability (controllability): ensuring the ease of management and control;
- User error protection: a degree to which the system protects the user against errors;
- User interface aesthetics: a degree to which the user interface satisfies the user and gives him pleasure from the interaction process;
- Accessibility: an ability to use a product or system by a wide range of people with a wide variety of opportunities ((including limited).
The best way to estimate the usability of the existing or new software is to implement the usability testing, inviting the real users to do the set of standard procedures as a test.