14 Oktober 2015

Usability - Introduction to usability

Definition of usability Usability is a quality feature that evaluates the usability of the user interface (UI). The word usability also refers to the method of improving usability as part of the design process - e.g. of web applications.

Usability is defined by 5 quality characteristics:

Learnability: How easy is it for users to do basic tasks when they first encounter the UI?
Efficiency: How fast / efficient can users perform their tasks once they have familiarized themselves with the user interface?
Memorability: How easy is it for users to restore their knowledge if they have not used the interface for a long time and then reuse it?
Errors: How many mistakes do users make and how strong are these? How much effort is involved in the correction?
Satisfaction: What is the feeling when using the user interface?

There are many more important quality features. Another key feature is the utility, which evaluates the functionality of the UI. The question here is: Does the UI fulfill the use cases that users need?

Usability and utility are equally important: both together are an indicator of whether the application should be classified as useful. Both features have an equivalence relationship: it is irrelevant if an application is easy to use, but does not fulfill the functionality users need. Conversely, it is unacceptable for the application - hypothetically - to be able to do the task, but users can not operate the UI efficiently enough. To identify and improve the utility of a design / product, you can use the same methods that we will introduce below for usability.

First, let's briefly redefine the important vocabulary to briefly summarize the previous paragraph:

Utility = Are there any functionalities required by the users to complete a defined task (or workflow, use case)?
Usability = How easy and enjoyable are these functions from the user's point of view?
Useful = usability + utility.

Why usability matters

Websites must have good usability in order to achieve good acceptance (resulting in conversion rates). They have to meet the minimum expectations of the user and, at best, even surpass them. In the worst case, the expectations of the visitors are not met, so that most likely leave the page disappointed, resulting in a high bounce rate, bad conversion rate and below average visit duration. These effects are - in the worst case - then clearly noticeable by a devaluation of the domain (position in the SERPs) by the search engines. The expectations of the users can be composed of several factors. So can be reasons for premature leaving the website:

  1. The users do not find their way around the website and - after some subjective considerations - do not reach their destination fast enough.
  2. And / or the content is not optimized accordingly to the target audience, for example, if the language does not correspond to the level of the target audience or the specific questions of these groups remain unclear.

Every company has to keep in mind that the World Wide Web offers a wealth of information and competing products, so that users are by no means completely dependent on their own site. Note: (almost) every website is replaceable! Psychologically, escaping is the first and most common defensive attitude of users when they encounter difficulties. Therefore, users will hardly make efforts, e.g. to find your way around the website if it is easily replaceable and not very attractive in content and appearance. The top rule in e-commerce is that if users can not find the product, then they can not buy it. For intranets, usability is a matter of employee productivity. Time spent wandering around the intranet or having to do inefficient work steps is paid and wasted working hours. Current best practices use about 10% of the budget (in terms of total development budget) for a thorough usability review. Tests can almost double the quality of the websites on average and can significantly increase the efficiency of using the intranet. For software and physical products, the improvements are generally smaller - but still significant considering usability in the design process. For internal projects: the effort put into usability can be compensated by savings in the duration of training and more efficient operation - which increases employee productivity. For external projects, testing can double sales, duplicate registered users, and / or duplicate any key performance indicator (KPI) underlying the project.

How to improve usability?

There are many methods for studying usability, but the most basic and useful approaches are user testing. These have three components:

  • Obtain representative users, such as customers for an ecommerce website or employees for an intranet (outside their own department).
  • Let test candidates perform representative tasks that reveal the weaknesses and strengths in the design.
  • Observe what and how the users do different tasks, where they succeed and where they encounter difficulties, for example. with the user interface. Do not justify the design, but gratefully accept the comments of the test candidates as constructive criticism.

In these tests, it is very important that the users are individually tested they solve all problems completely independently. Any interaction - or assistance - could seriously distort the results of the tests, because the website visitors can not be helped immediately.

As a rule, five users are sufficient to identify the main usability problems of a design. Rather than conducting a large and expensive study, it is usually more useful to distribute the resources over many smaller tests in order to be able to representatively represent the progress between the individual tests.
Thus, the identified deficiencies can be corrected and then directly tested again in a new test. This iterative approach is an effective approach to increasing the quality of usability and thus the quality of the product. After all, the more variants and interfaces that are tested with the right users, the better the end product will ultimately be.

The development department also likes to use so-called focus groups: these can be useful in the design of the product, but they are only conditionally recommended for the usability tests. For less important (not entirely unimportant!) Are the personal opinions and feelings of the subjects, as the results that could be obtained by a focused and objective observation of the subjects while they interact with the product.

When to work on usability

Usability plays an important role in every step of the development process. We recommend the following approach:

  • Before starting the new UI, the old UI should have been thoroughly tested. Identify and emphasize the good parts you want to keep and the bad parts that can cause problems for the users
  • If possible, competitors should also be tested and analyzed in order to gain inspiration for implementation (both positive and negative).
  • Conduct a field study to analyze the behavior of users in their natural environment
  • Create prototypes from one or more new design ideas (wireframes, prototyping) and test them. The less time invested, the better, since after good testing, the ideas generally have to be reworked again - based on the new test results.
  • Focus on the design of the UI that has performed best in the tests and refine this design. Test each of the iteration steps - from low-fidelity prototyping (on paper, for example) to high-fidelity representations (wireframes, clickable prototypes, etc.)
  • Check if the draft complies with the most recent and widely used usability guidelines; Include results from previous tests as well!
  • If the final design for the UI design is ready, test it again. In the projects which can be used to leverage the usability optimization.

The usability tests should not take place until the end of the project, as early testing can identify structural ills already in their infancy and you are still flexible enough in the process to correct them accordingly. It's similar to building a house: first the house is built, then it is (almost) impossible to mend the foundation. Therefore, be happy about any critical flaw that you can identify as early as possible in the iterative process and fix it. Similar to a house, a structural change in your product - the further the project has progressed - can be very costly and therefore very expensive.

We therefore recommend that you carry out the tests as soon as possible in order to achieve an end product with higher usability and to regard this iterative procedure as a natural process that constantly accompanies the development. Understand it as a chance to simplify the development process and ultimately gain a higher quality product that is much better adapted to the needs of the users than some other competitors.

Where the tests should be done

If many studies are to be carried out, then a separate laboratory could pay for it. But for most companies, it will be enough to provide a separate (conference) room for the tests, which is isolated and quiet. A door here is a clear added value, because you can close this. Since one should focus on the subjects, we only recommend the use of a notebook, so observations can be quickly recorded and possibly also quickly made simple sketches.

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