user friendliness

from Wikipedia, the free encyclopedia

Ease of use describes the quality of use experienced by the user when interacting with a system . A particularly simple operation suitable for the user and his tasks is seen as user-friendly.

Ease of use is to be understood analogously to terms such as skin-friendly : friendly to the user. In order to avoid confusing interpretations of the original English term user-friendly and the lack of scientific precision, the term " usability " of a (software) product is used in standardization contexts . This in turn is defined in Part 11 of the DIN EN ISO 9241 series of standards as the product of effectiveness , efficiency and satisfaction . This definition can also be transferred to all other tools and media. For users, however, the concept of user-friendliness is more intuitive and also takes more into account the emotional aspects of the overall user experience , the so-called user experience .

Objective ergonomics

Ease of use is closely related to ergonomics . While hardware ergonomics is understood to mean the adaptation of tools to the human movement and perception apparatus (e.g. body forces and spaces of movement), software ergonomics deals with the adaptation to the cognitive and physical abilities or characteristics of humans, that is, its options for processing information (e.g. complexity) but also software-controlled characteristics of the display (e.g. colors and font sizes ).

The aim is to take people and their tasks and skills into account and to adapt the tool (be it software or any other tool) to it.

1965 formulated Gordon Moore , the Moore's Law , according to which the complexity of integrated circuits doubles approximately every 18 months. The Canadian designer William Buxton finds a similar pattern for the development of the functionality of technology. The biophysical, cognitive development of humans cannot keep up with this. For this reason, a user-friendly design that is tailored to the capabilities of the person should always be aimed for.


By far the largest part of information about the outside world (around 80%) reaches people through the eyes. It is much easier to process and retain information that has a known structure.

Too much information overloads the cognitive system. Through abstraction, filtering and the recognition of causal relationships, sensory impressions are evaluated and sorted. This process is called " chunking " in psychology . Generally, the model of the “magic 7” ( Miller's number according to George A. Miller ) is applicable to human memory .

There are also disruptive factors that can reduce this number. It is important to remember an intermediate goal, you may be demotivated, in a bad mood, under stress, tired, intoxicated, etc. In addition, the memory while surfing does not go back further than approx. 4–5 screen pages. On average, three to five conceptual units remain in short-term memory.


Intense colors, strong contrasts, sharp contours as well as complex shapes and elements that stimulate intellectual debate stimulate attention. The other stands out. On the other hand, large areas, pastel tones and muted, broken or darkened colors are eye-friendly and pleasant . Special "eye catchers" are highly saturated red and warning colors such as black and yellow, animations, faces, eyes, the child schema or sexual representations. If too many of these attention-grabbing elements appear, they become distracting again.

Reading styles

The presentation of a screen or a website must meet different reading requirements. Users with floating attention have an ambiguous view of the entire content and “scan” the text for the most prominent parts. They cover around 50% of the content. A user with focused attention filters what is perceived. It "skims" for a specific search term and covers around 30% of the total content. A particularly varied presentation will please the first type of reader, but depress the second type.

Reading text on the screen is more difficult than reading books or magazines. As in any text, headings should be stronger, a distillate of the content and not contain any puns or irony. It is also beneficial to include important information in the first word or at the beginning of the text. Scanning is made even easier if each page does not start with the same word and a distinctive structure is generally recognizable. Key stimuli when scanning are terms such as news, stock exchange, travel, money, digital, jobs, mobile, etc.

In addition, texts that do not contain useful information and do not meet the needs of the user should not be written in the “brochure style”. (see above: Information, entertainment, shopping) "We are a progressive company in the XY sector that creatively uses the latest developments in information technology for its customers."


Many individual elements contribute to increasing legibility .

  • Contrast between text and background: Black text on a white background offers the best contrast.
  • Backgrounds should be monochrome, not distracting or only have subtle patterns.
  • Static text (no blinking or resizing)
  • sans serif fonts especially for small texts (Verdana, Arial)
  • Use emphasis in the text such as underlining and capitalization of whole words sparingly


The navigation should be quickly recognizable and comprehensible. This is made easier by breadcrumbs and a less nested structure. Alternative terminology should not be used that deviate from the conventions and confuse the user too much. (For example, the designation of the “shopping cart in a shop system as a 'shopping sledge'”, see Nielsen p. 188)


A clear structure and simple operation should make the page as accessible as possible and provide the user with the desired information as quickly as possible.


There are certain design conventions (see design tasks above) that recur and are therefore assumed or assumed by the user. In western cultures, text flow is expected from left to right. Objects have meaning according to their size. At the top of the page is the most important thing.

Design tasks

The task z. B. a web page is always first to meet the needs of the customer. The customer wants to be informed, entertained, or buy something. To ensure this as well as possible, the page must clearly convey its content. (Where am I? What does this page do? Where have I been? Where can I go?) The information should be clearly presented in clear hierarchies and grouped in a meaningful way. The page has to be fast because the user is impatient and wants to get information quickly. The goal is the greatest possible processing depth " Depth of Processing " (Craig and Lockhart), the strongest possible memory of what has been seen.

Operation is simplified by standards such as a fixed layout or fixed terminology. The activation of already learned procedures for operating technical systems enables intuitive operation.

Evaluation of quality

The evaluation of the user friendliness can in principle be done using different methods:

Each of these methods has its specific strengths and weaknesses, especially with regard to their validity , reliability , representativeness and efficiency . Expert reviews suffer from the fact that they also depend on the skills of the expert and cannot always be reliably reproduced by other experts . Surveys, on the other hand, occasionally lull the interviewer into a false sense of security, as the development of measuring instruments (such as questionnaires) is often underestimated.

Test methods

In usability tests, typical users are confronted with typical tasks with the product to be evaluated (an " artifact " such as software, a website, interactive devices and tools) and systematically observed during use. The usability test applies i. A. as one of the reference methods for evaluating usability; However, it can be comparatively more expensive than the other methods due to the use of laboratories, video technology and other aids as well as the more complex evaluation. However, these costs can be reduced with simple means through "on-site" tests. The usability test is certified in the literature that it can identify 80% of the usability problems contained in a product with around 5 users (depending on the complexity of the test object). Even with usability tests, there is a risk that inaccurate test setups, priming and uncritical evaluation can lead to falsifications. Laboratory situations in particular occasionally generate untypical care or other unrepresentative behaviors in the test subjects.

A remote usability test is carried out for the test persons in their "natural environment", e.g. B. performed at home or at work. With the help of a special remote system, the test subjects are observed while they are performing their activities over the Internet. The remote usability test offers various advantages compared to a usability test in the laboratory:

  • The test subjects are not influenced by the unfamiliar test environment or an interviewer.
  • With the remote test, a significantly higher number of users can be observed over the same period.
  • It is economically possible. also test users in remote areas as long as they have an internet connection.

There are now a large number of remote usability test systems. These are usually suitable for websites and software.

One shortcoming of these remote tests, however, is that the test leader cannot see the test subjects (or only through a webcam) and so important information from the user's reaction remains hidden. Some remote testing tools are even limited to allowing users to submit comments on usage at the end of a session, which is not a usability test.

A very fundamental problem in the assessment by laypeople is often that the context of use is not systematically taken into account, but that general statements are inferred from individual experiences. Unfortunately, such blanket statements are also supported by the media that certify that a product is in fact universal usability without taking into account the special requirements that have to be assumed when using the product.

Another problem with a superficial layman's view is that user-friendliness seems rather inconspicuous (“intuitive to use”), while poor usability is perceived, but the exact cause cannot be named.

The focus of every evaluation is often the usability criteria according to DIN EN ISO 9241-110 such as B. Appropriateness of the task . The appropriateness of the task describes the extent to which the website or the tool fulfills the requirements of the task (informing, amusing, writing an invoice or ordering a book).

Web usability

Like any other technical aid, a website must meet certain requirements in order to be user-friendly. It is important to adapt the presentation of the content to the human receptivity.


The International Standards Committee has published various ISO standards that are of interest in terms of usability:

ISO 9126 (DIN 66272)
Evaluating Software Products - Quality Attributes and Guide to Using Them
ISO 9241
Ergonomic requirements for office work with display devices
ISO / IEC 12119
Software products - quality requirements and test provisions
ISO 13407
User-oriented design of interactive systems
ISO 14915
Software ergonomics for multimedia user interfaces


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Web links

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