Usability test

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Test person in a usability laboratory at Siemens in Munich-Neuperlach (2000)

A usability test is carried out to check the usability of software or hardware with potential users. It belongs to the techniques of empirical software evaluation , in contrast to analytical methods such as cognitive walkthrough .

Within a development process, for example a website design, a redesign process - classic, scenario-based usability tests (as presented in detail below) are mainly carried out when click dummies or beta versions have been created. The focus is on the detail optimization of interaction processes (such as the ordering process in an online shop).

Delimitation of the term

Simply collecting opinions on an object or document counts as market research or qualitative research and not referred to as a usability test. Usability tests usually involve systematic observation under controlled conditions to determine how well users can use the product. Often, however, both qualitative tests and usability tests are used in combination in order to better understand not only the actions of the users but also their motivations / perceptions.

Instead of showing users a rough draft and asking, "Do you understand?", Usability testing involves watching people try to use something for its intended purpose. For example, if instructions for assembling a toy are being tested, the test subjects should be given the instructions and a box of parts. Instead of being asked to comment on the parts and materials, they are asked to assemble the toy. The wording of the instructions, the quality of the illustrations and the design of the toy all influence how the toy is assembled.

Test variants

In addition to scenario-based usability tests in the laboratory, there are other test variants, for example, which are suitable for different questions or problems in the development process:

  • Expert-based usability evaluations
  • On-site surveys (including benchmarking )
  • Drop-out analyzes with the help of user tracking tools and (event-related) on-site surveys
  • Concept / design tests (online and offline)
  • Online usability tests via task-based online surveys and tracking of click behavior .

method

In a usability test, test subjects are induced to solve typical tasks with the test object that they would later complete in a similar form with this product. It is checked at which points difficulties arise during use.

The test subjects are asked to think aloud so that the observer learns what the person is looking for and what he or she is thinking of among the options offered.

A developer easily overlooks weaknesses in their own product and tends to defend it. Other employees of the company are biased as test subjects because they have prior knowledge of the structure of the company and the names and purposes of its products and services; Knowledge that an outside visitor lacks. For this reason, developers should not appear as test subjects or test managers in the usability test, and other company employees should also not appear as test subjects. Instead, usability experts recommend using an independent evaluation team. If the test persons need to be instructed by the test personnel, precautions must be taken to ensure that the test persons do not receive any tips on how to use the software or the website, which would falsify the test results.

Surveys can take place before and after the test. An initial survey can be used to select suitable test subjects. Prior to the usability test, the subject's previous knowledge, e.g. experience with similar products, is queried. Sometimes card sorting techniques or wording tests are used for this. Various other testing tools such as written instructions, paper prototypes, and pre- and post-test questionnaires are also used to gather feedback on the product being tested.

After the test, information about the tested product is requested. Semi-structured interviews are held for this purpose. Their implementation places high demands on the interviewer. As part of these surveys, comparisons with other products are often made. The test persons are asked what advantages and disadvantages there are compared to similar products. Since classic, scenario-based tests are usually carried out with a small sample (5 to a maximum of 30 test persons), the results of such comparisons can only show initial tendencies with regard to any assessment differences.

After the usability test, the weak points are analyzed and the product is optimized in such a way that as many people as possible perceive it as easy to use, thereby improving user-friendliness .

recording

In order to be able to log usability tests and ultimately possible weak points as precisely as possible, various forms of recording are used:

  • Sound, video and screen recording
  • Tracking software to record, for example, mouse movements, mouse clicks, keystrokes and websites visited (for web usability) by the user
  • Eye movement registration
  • observation

After the test, all protocols (text protocols, video, eye movement data) are evaluated.

Applications

In principle, usability tests can always be carried out when something is subject to human-machine interaction. Both software and a real object are possible objects of investigation.

Examples are:

Other test methods

Usability tests can also be carried out as benchmark tests, for example to find out whether a product is already sufficiently usable. For example, a usability goal could be to improve a web application for booking a flight until a user manages to book a flight within three minutes. In this case, the usability test measures the time for this task and does not think aloud. The usability test controls the prototyping process.

Usability tests are also carried out as comparative tests, for example when purchasing software. It is tested which product has the better usability.

The implementation often takes place in usability laboratories . In the meantime, however, there are also providers who offer “remote usability tests” or “crowd usability tests”. The testers are not invited to a laboratory, but test from home. Since no laboratory is required for the tests and the testers work from home, this method can achieve significant cost savings.

Eye tracking in usability research

Evaluation of eye tracking data after a usability test

Eye tracking or eye movement registration is used, among other things, in usability and concept tests to record the eye movements of test subjects. This makes it possible to determine which areas of a screen the user has viewed and how intensively he has viewed them. In addition, it is possible to identify areas or elements that have received little or no attention. Data from eye tracking / gaze progression studies provide valuable insights into the optimization of layouts and designs. Thus, eye tracking is used more and more often in the early phases of a development process (on designs and prototypes) and iteratively in several stages. This is supported by the advent of cheap eye-tracking hardware and alternative forms of recording such as remote usability tests via the webcam.

Eye tracking provides information on this

  • Which elements of the screen the user is paying attention to
  • Which elements a user sees, which not
  • How important an area is for a user
  • Whether a user is oriented or disoriented
  • Whether a text is read through

In-store tests, remote tests, proxy procedures

Test procedures in the usability laboratory, in which participants are observed and questioned on site, usually require budgets that are out of the question for small website projects. Therefore, in such cases, economical procedures such as in-store tests, remote usability tests or the proxy procedure are used.

In the in-store test according to Jakob Nielsen , the test manager tests a paper prototype or click dummy on the website in the customer's shop with five randomly present customers as test subjects.

With remote usability tests, the entire usability test process is carried out online. One refrains from recruiting test persons locally and inviting them to a laboratory or one's own office. As a rule, these tests are carried out by a specialized provider who provides its own panel of test persons, from which people can be recruited based on various criteria such as age, gender, Internet experience, shopping behavior, etc. The duration of such a test varies depending on the target group between a few hours and several days. One of the newer methods that have been developed for performing a synchronous remote usability test is the use of virtual reality environments .

In the proxy process, user access to a website is redirected via a proxy server . This saves the call order and viewing time of the individual pages, as well as all user input. If you now give the user tasks, for example to find out about the offer on the respective page, you can use the stored data to assess both the clarity of the layout and the understandability of the texts. The advantage is that neither the code of the page has to be changed nor its functionality is impaired. The origins of this process go back to the late 1990s. The web event logging tool WET developed by AT&T in 1999 and the WebQuilt developed in 2001 are considered pioneers.

Special features of medical devices

Usability test in the experimental operating room in Tübingen

Since medical devices are generally safety-critical devices, special requirements for usability tests must also be made for these devices. In addition to the usability factors of efficiency, effectiveness and satisfaction, safety must also be taken into account. The "UseProb" method combines the requirements of usability with those of risk management. The usability test should also be carried out in a special usability laboratory (e.g. an experimental operating room ) in order to simulate a typical usage environment and situation. Special requirements for the verification and validation of the usability of medical devices are specified in the standards DIN EN 60601-1-6 and DIN EN 62366 .

Special features of modeling languages

In addition to the already existing procedures for determining the user-friendliness of various objects of investigation such as applications, websites, methods etc., usability tests can also be used to evaluate modeling languages. The aim can be to check a newly developed modeling language or extension against existing notations with regard to their usability. Both the aspects of the creation and the interpretation of a model can be tested, with direct usability attributes and usability-influencing meta properties of models playing a role. The usability attributes of modeling languages ​​are specifically measured and calculated in the test using metrics . Of the 28 publications examined in 2013 on the subject of “Measuring the Usability of Modeling Languages”, 18 set the definition of usability, ideally in the form of individual attributes. The criteria learnability, effectiveness, efficiency and user satisfaction were mentioned in more than a third of the sources examined as criteria of usability. The calculation of metrics that can be used to measure these criteria are largely the same across all publications.

literature

  • F. Sarodnick, H. Brau: Methods of Usability Evaluation. Hans Huber, Bern 2011.
  • Andrew Duchowski: Eye Tracking Methodology - Theory and Practice. 2nd Edition. Springer, London 2007, ISBN 978-1-84628-608-7 .
  • David Kratz, Konrad Scherfer: Qualitative-analytical usability evaluation as a genuinely web-scientific method. In: Konrad Scherfer (Hrsg.): Theory and Practice of the Web - Basic Considerations of a Future Web Science . LIT, Münster 2008, ISBN 978-3-8258-0947-8 .
  • Martina Manhartsberger, Norbert Zellhofer: Eye tracking in usability research: What users really see. Usability Symposium, 2005, pp. 141–152.

Individual evidence

  1. ↑ Jakob Nielsen: Why You Only Need to Test With 5 Users. . Alertbox, March 19, 2000, accessed October 29, 2015.
  2. ↑ Optimize online shops from the user's point of view. ( Memento of the original from December 9, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Deutsche Messe Interactive - Director's Letter. March 2013. (PDF; 780 kB) @1@ 2Template: Webachiv / IABot / www.testhub.com
  3. ↑ Jakob Nielsen: Usability for $ 200. Alertbox, June 2, 2003, accessed October 29, 2015.
  4. ↑ M. Etgen, J. Cantor: What does getting WET (Web Event-logging Tool) mean for Web Usability? in CHI '06 extended abstracts on human factors in computing systems
  5. ↑ JI Hong, J. Heer, S. Waterson, JA Landay: WebQuilt: A proxy-based approach to remote web usability testing . In: ACM Transactions on Information Systems. 19, No. 3, 2001, pp. 263-285.
  6. ↑ D. Büchel, M. Scherrer, U. Matern: Example: User-centered development processes for an emergency device that is not used every day. In: A. Hermeneit, J. Stockhardt, A. Steffen: The CE route planner - planning, developing, realizing medical devices. TÜV Media GmbH, Cologne 2009, ISBN 978-3-8249-1100-4 .
  7. ↑ K. Figl J. Mendling, M. Strembeck, J. Recker: On the Cognitive Effectiveness of Routing Symbols in Process Modeling Languages . 2010.
  8. ↑ Christian Schalles: Usability Evaluation of Modeling Languages ​​- An Empirical Study . 2013.

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