AHL Topic 7: User Centered Design A

User-centered design (UCD) is a process (not restricted to interfaces or technologies) in which the needs, wants, and limitations of end users of a product, service or process are given extensive attention at each stage of the design process. User-centered design can be characterized as a multi-stage problem solving process that not only requires designers to analyse and foresee how users are likely to use a product, but also to test the validity of their assumptions with regard to user behaviour in real world tests with actual users. Such testing is necessary as it is often very difficult for the designers of a product to understand intuitively what a first-time user of their design experiences, and what each user's learning curve may look like.

The chief difference from other product design philosophies is that user-centered design tries to optimize the product around how users can, want, or need to use the product, rather than forcing the users to change their behavior to accommodate the product.

During the past twenty years, user-centered research (UCR) has become an increasingly common and important part of contemporary product development. The origins of this approach to design and development actually stretch back to the beginning of industrial design in America. Starting in the 1940s and 1950s, Henry Dreyfuss (widely considered the father of industrial design in the United States) preached and practiced a method of design that clearly focused on studying people’s behaviors and attitudes as a first step in designing successful products. During the next forty to fifty years, Dreyfuss’s example served to motivate other

highly successful and influential designers (e.g., Robert Probst, Jay Doblin, Niels Different, and William Stumpf) to adopt a user-centered approach to their design work.

The most valuable asset of a successful design team is the information they have about their users. When teams have the right information, the job of designing a powerful, intuitive, easy-to-use interface becomes tremendously easier. When they don’t, every little design decision becomes a struggle. Field studies get the team immersed in the environment of their users and allow them to observe critical details for which there is no other way of discovering.

Using an Iterative, Cyclical Design Process

Iterative design is a design methodology based on a cyclic process of prototyping, testing, analyzing, and refining a product or process. Based on the results of testing the most recent iteration of a design, changes and refinements are made. This process is intended to ultimately improve the quality and functionality of a design. The key requirements for Iterative Design are: identification of required changes, an ability to make changes, and a willingness to make changes. When a problem is encountered, there is no set method to determine the correct solution. Rather, there are empirical methods that can be used during system development or after the system is delivered, usually a more inopportune time. Ultimately, iterative design works towards meeting goals such as making the system user friendly, easy to use, easy to operate, simple, etc.

The five stages of UCD: ● research ● concept ● design ● implementation ● launch

An iterative, cyclical design process lends itself easily to user-centered design. User-centered design includes four important tenets identified by Gould, Boies, and Lewis (1991):

• Early focus on users. Designers should concentrate on understanding the needs of users early in the design process.

• Integrated design. All aspects of the design should evolve in parallel, rather than in sequence. Keep the internal design of the product consistent with the needs

of the user interface.

• Early and continual testing. The only currently feasible approach to User-centered design is an empirical one: the design works if real users decide it works.

Incorporating usability testing throughout the development process gives users a chance to deliver feedback on the design before the product is released.

• Iterative design. Big problems often mask small problems. Designers and developers should revise the design iteratively through rounds of testing.

Multidisciplinary Teams

UCD requires that specialists from several disciplines create the total customer experience. These roles can be organized into a conceptual team structure, which includes individuals who design, those who are architects, those who provide information, and those who lead. The work of all these individuals is informed by guidelines, processes, and tools, as well as by customer input and user evaluation. Even though all these categories of roles come together and synergistically create the total customer experience, it is important to point out the differences in the contributions made by each.

UCD Role Terminology Responsibility Skills

User experience Program manager, design lead, creative integrator, Has responsibility for the total customer experience Vision, leadership, technical expertise, project and design lead creative lead, creative director, ease of use lead, design of the project people management, facilitation user experience design lead

Product manager, marketing, packaging engineer Specifies the target market, user audience, key Marketing, market intelligence, market trends, Marketing specialist ​ competitor, market ease of use objectives, and ease synthesis of information, teamwork of use messages as well as the channel, packaging, and terms and condition requirements

Visual/industrial Industrial design, mechanical design, graphics Has responsibility for the overall appearance, layout, Art, design, model/prototype building, creativity, designer designer, media designer, artist, visual interface balance of the software offering including the consistent teamwork architect, mechanical engineer, director visual signature of the advertising, packaging, and product design

Human-computer User interaction design, user interface design, Responsible for specifying the task flow, interaction Human-computer interaction, conceptual modeling, interaction designer interaction designer, designer, product designer, HCI design, and division of tasks to be carried out by the information synthesis designer, HCI specialist, information architect user and by the computer

User assistance User communication design, user assistance Has responsibility to specify the appropriate user Information architecture, teamwork architect designer, user assistance architect, writer, assistance mechanisms for the offering information designer

Technology Programmer, technologist, architect, software Has responsibility for specifying the underlying Technical skill in relevant domain, development architect designer, UI programmer technology required to implement the desired total process, programming and/or engineering customer experience teamwork

Service and support User support specialist, service planner, service and Specifies the service and support that should be delivered technologies and options specialist support engineer with the offering

Usability specialist, usability engineer, human Has responsibility for the design, analysis, and Usability engineering, technical aptitude, UCD User research ​ specialist factors engineer, user experience specialist, user interpretation of UCD studies carried out on the methods experience architect, user research specialist, user project including the articulation of feedback specialist recommendations coming from this applied research

Internationalization/ Localization designer Is responsible for ensuring that the offering Internationalization and localization specialization, terminology appropriately addresses the needs of the terminology, languages, HL enablement specialist international audience within the target market and for specifying the appropriate terminology to be used in the offering

UCD project lead Program manager, project manager, product Has overall responsibility for UCD deliverables and Project management, UCD process, development manager plans as well as the integration of them into the process development plan

The primary notion of usability is that an object designed with a generalized users' psychology ​ and physiology in mind is, for example: ​ ​

• More efficient to use—takes less time to accomplish a particular task ​ ​ • Easier to learn—operation can be learned by observing the object ​ ​ • More satisfying to use

In the user-centered design model, the product is designed with its intended users in mind at all times. In the user-driven or participatory design model, some of the users become actual or de facto members of the design team.

The term user friendly is often used as a synonym for usable, though it may also refer to accessibility. Usability describes the quality of user experience across websites, software, products, and environments.

There is no consensus about the relation of the terms ergonomics (or human factors) and usability. Some think of usability as the software specialization of the larger topic of ergonomics. Others view these topics as tangential, with ergonomics focusing on physiological matters (e.g., turning a door handle) and usability focusing on psychological matters (e.g., recognizing that a door can be opened by turning its handle).

Designed products surround us all and range from bus tickets to buildings. One of the primary considerations in all fields of design is ‘usability’ and, increasingly, the phenomenon of ‘user-centred design’. This can focus on physical attributes of products but increasingly it depends on an understanding of our cognitive abilities required to operate even simple products.

We all have some experience of designs that are not usable (perhaps mobile phones or car controls).

Products should be user friendly. This applies to the cars we drive, the tools we use and the various computer devices we depend on to access information daily. Sadly, many products are not very usable. Mobile phones with unusable micro buttons, DVD recorders that cannot be understood, toasters that burn, jars with lids that cannot be removed. These are not failings on the part of the consumers – what is needed is a better and more people-centred design approach.

People Centred

Of course usability is just one of the many factors that designers need to be aware of. Products need to be manufacturable, they need to use materials that are suitable, they need to be sustainable and they need to be available to consumers at a certain price. Nevertheless, design must be first and foremost people-centred.

Usability objectives

According to ISO 9241, the dimensions of usability are:

• effectiveness: the accuracy and completeness with which users achieve specified

goals

• efficiency: the resources expended in relation to the accuracy and completeness

with which users achieve goals

• satisfaction: the comfort and acceptability of use

Effectiveness measures usability from the point of view of the output of the interaction. The first component of effectiveness, accuracy, refers to the quality of the output and the second, completeness, refers to the quantity of the output in relation to a specified target level. Efficiency relates effectiveness of interaction to resources expended. It may be measured in terms of mental or physical effort, time, materials or financial costs.

New technology offers the potential for real improvements to our lives – products that make jobs easier, quicker or give better results. But all too often the conversion of a technology into an artefact results in products that are difficult to understand and use. Some ‘usability’ problems are very obvious and we see them before we buy. For example a mobile phone where the buttons seem too small for our fingers to operate or a camera that seems too complicated to understand. In these cases we have advance warning and can find alternative products to purchase. But many usability problems only become apparent AFTER we have purchased a product. One of the most important purposes of design is to represent the users in the product development process. Good design makes innovation understandable and usable for the intended market. But designing products to be usable is only one of many concerns for a manufacturer.

OXO GOOD GRIPS

OXO began with a few simple questions - Why do ordinary kitchen tools hurt your hands? Why can't there be wonderfully comfortable tools that are easy to use?

The man who asked these questions was Sam Farber, an entrepreneur in the housewares industry. Noticing that his wife Betsey was having difficulty gripping ordinary kitchen tools due to a slight case of arthritis in her hands, he saw an opportunity to create more comfortable cooking tools that would benefit all users.

After hundreds of models, dozens of design iterations, and extensive research, OXO was born. In 1990, the first group of 15 OXO Good Grips kitchen tools was introduced to the U.S. market. These ergonomically-designed, transgenerational tools set a new standard for the industry and raised the bar of consumer expectation for comfort and performance.

Today, OXO offers over 850 products covering many areas of the home. Each was developed based on the concept of Universal Design (also known as Inclusive Design), a philosophy of making products that are usable by as many people as possible. The concept of Universal Design makes room for all users by taking as many needs as possible into consideration in the design process. For OXO, it means designing products for young and old, male and female, left- and right-handed and many with special needs.

Since the introduction of the first Good Grips peeler, many other products have been added to the OXO range – and many other producers have taken up the design, manufacturing and marketing principles embodied in the original product.

Designing for users

Although most producer companies devote major resources to researching the market for their products, many products still appear on the market that seem not to have been designed with their user in mind. You must have experienced or noticed some dangerous, baffling or irritating product design failures yourself. Perhaps sometimes you thought the failure lay with you, in not understanding how to use the product. Maybe you thought the designers just had not made the product sufficiently idiot-proof! But wait – you are not alone. Even professors of psychology get baffled by everyday objects. Here is a short extract from The Design of Everyday Things by Professor Donald Norman.

If I were placed in the cockpit of a modern jet airliner, my inability to perform gracefully and smoothly would neither surprise nor bother me. But I shouldn't have ​ trouble with doors and switches, water faucets [taps] and stoves. ‘Doors?’ I can hear the reader saying, ‘You have trouble opening doors?’ Yes. I push doors that are meant to be pulled, pull doors that should be pushed, and walk into doors that should be slid. Moreover, I see others having the same troubles – unnecessary troubles. There are psychological principles that can be followed to make these things understandable and usable.

Why are so many everyday objects not only difficult to use but actually dangerous? Many domestic accidents are associated with using everyday objects such as scissors, knives, can-openers and garden tools and machines. These are perhaps inherently dangerous things that need care in their use, but many accidents also result from perfectly normal use of things such as cookers, heaters and even furniture. Of course, many domestic accidents involve young children, or elderly or infirm people; relatively young, healthy adults are less accident-prone. But surely designers realise that not everyone is a young, healthy adult?

Most designers do recognize that often they are designing products for a wide range of users. It is not fair just to blame designers, when they are working to requirements laid down by producer companies and manufacturers, to quality standards set by retail company buyers, and to cost limits set by prices that consumers are prepared to pay.

Characteristics of good user-product interfaces

• Clarity: The interface avoids ambiguity by making everything clear through language, flow, hierarchy and metaphors for visual elements.

• Concision: It’s easy to make the interface clear by over-clarifying and labeling everything, but this leads to interface bloat, where there is just too much stuff on

the screen at the same time. If too many things are on the screen, finding what you’re looking for is difficult, and so the interface becomes tedious to use. The

real challenge in making a great interface is to make it concise and clear at the same time.

• Familiarity: Even if someone uses an interface for the first time, certain elements can still be familiar. Real-life metaphors can be used to communicate

meaning.

• Responsiveness: A good interface should not feel sluggish. This means that the interface should provide good feedback to the user about what’s happening and

whether the user’s input is being successfully processed.

• Consistency: Keeping your interface consistent across your application is important because it allows users to recognize usage patterns.

• Aesthetics: While you don’t need to make an interface attractive for it to do its job, making something look good will make the time your users spend using

your application more enjoyable; and happier users can only be a good thing.

• Efficiency: Time is money, and a great interface should make the user more productive through shortcuts and good design.

• Forgiveness: A good interface should not punish users for their mistakes but should instead provide the means to remedy them.

Population Stereotypes

Population stereotypes: responses that are found to be widespread in a user population. “Long-term habits and well-ingrained knowledge that we have about the ​ ​ world” (Kantowitz & Sorkin, 1983). ​ ​

Making use of population stereotypes in the design of the controls for products is relevant. It is usually anti clockwise for ‘on’ when dealing with fluids and gases (a tap) ​ ​ ​ ​ and clockwise for ‘on’ when dealing with mechanical products (a radio). ​ ​ ​ ​

Light switches generally follow the pattern of Up for the US and Down for the rest of the world.

Population stereotypes can be displaced (changed or relearned) by alternative learnt responses, but they frequently reassert (return) under conditions of stress such as tiredness or panic.

Case Study

Below is an extract from “A scrapbook of illustrated examples of things that are hard to use because they do not follow human factors principles”. By Michael J. ​ ​ ​ ​ ​ Darnell

“A friend told me he was confused by the switches on his coffee maker (See ​ photo.) Each switch has a light on it. The top switch turns the coffee maker on and off. When it is on, its light goes on. No light appears when the coffee maker is off. The bottom switch selects the quantity of coffee desired, either a) the smaller quantity of 3 or fewer cups or b) the larger quantity of 4 or more cups. The problem is with the light on this bottom switch. When would you expect the switch light to go on, for the smaller quantity or for the larger quantity? If you said that the light goes on when the switch is set to the larger quantity of 4 or more cups, you would be wrong. The quantity light ONLY goes on for the smaller quantity, three cups or less. It does NOT go on for the larger quantity, 4 or more cups.” ​

Why is this confusing? People naturally expect more coffee to be associated with more light (light on) and less coffee to be associated with less light (light off).

Converging technology in product design may also lead to a confusing control layout. E.g. gas cooker controls are turned clockwise for ‘off’ but for an ​ ​ ​ ​ electric cooker they are the other way round. This is because the gas cooker knobs are effectively taps, operating a fluid or gas. This can be confusing for consumers and be a safety hazard, especially with a gas hob and electric oven combined into one product.

Activity

In the following three examples you are forced to learn which controls operate the burners. The spatial arrangement of the controls in relation to the burners is ambiguous (open to more than one interpretation; having a double meaning). Often producers try to reduce this problems by placing icons next to the controls to indicate which burner it operates (mapping). But it still requires you to look at the icon every time. After many repetitions you might have learned which burners the controls operate but what happens if you are going to cook at another stove? Exactly, you have to learn it again, another long painstaking process.

Easy to use products are characterised by a short or even no learning curve.

User population

User Population: The range of users for a particular product or system.

Large user groups may be defined by age, gender, physical condition, economic means etc. When considering a product designed for mass use, it is not good to rely on information collected from just a few people, as it is unlikely to be representative of the whole range of users. Therefore it is important to use ‘sampling’ across the population groups to gain information about potential users. ​ ​ ​ ​

When deciding which user group sample to use for a product it is vital that you have identified all areas of the target audience and have given equal opportunity for users from all of these to partake. To further define the exact nature of a user group sample it is important to understand the characteristics that are important to the final evaluation. These characteristics are the ones that must be represented by the members of the sample.

Who are the users?

Uers can include a wide variety of people – not just the final purchasers or consumers of a product. The section also makes the case for strong user representation in the design process.

In addition to the obvious or intended users there is a variety of people who have to interact with the product in various ways at different times, such as the people who make it or assemble it.

To manufacture the product people have to shape material, drill holes in components, and so on. During assembly people have to pick up the different pieces and put them together. During installation the product has to be transported, fitted into place, connections made and performance tested perhaps. The product has to be maintained and repaired by people during its working life. Finally, product components are often recycled or reprocessed; the different materials have to be separated and this is usually done by hand.

All these stages involve people in one way or another and so, ideally, a full usability evaluation would examine not only how well the product suited the capabilities, limitations and requirements of the user in the sense of the consumer, but all the other people who interact with it as well. For instance, how many times have you tried to repair something, only to find that you do not have the right tool, or the interior parts are inaccessible?

Manufacturing requirements can often override even consumer needs. That is because manufacturing and assembly difficulties cost money through lost time, faulty products, accidents and worker dissatisfaction.

Why not design for the ‘average’ user ​ ​ ​ ​ Even when user needs are being considered in design, it is still relatively easy for the designer to fall into the trap of designing for the average user. On the face of it, it seems a good idea to design for the average user. Obviously people do vary but there are limits to variation and surely it should be possible to design around the needs of the majority of average people?

The problem is that although it is relatively easy, for example, to measure body dimensions of a large group of people and determine what the average values are, it is quite difficult to find individuals who are average in more than just a few of these. An experiment conducted in the United States of America illustrates this point (Bailey, 1982). The averages of a large number of physical body dimensions such as standing height, arm length or chest circumference are already well known for US adult men. For this study, 4063 males were selected at random and measured to see how well they conformed to the known averages for their population.

The first measurement was of standing height and out of the original sample of 4063, only 1055 or 25.9 per cent were found to be close to the average. The rest of the sample were allowed to go home and the experiment continued with only those who were of average height. They were next measured for chest circumference and it was found that only 302 or 7.4 per cent of this group were of both average height and chest measurement. All those not average in both respects were sent home and the experiment continued in this way, working through ten simple dimensions in all.

By the time the experimenters got to the tenth set of measurements only 2 subjects were left in the sample and after the tenth measurement even they were eliminated. They had run out of people to measure. No-one from the original sample of 4063 subjects was average in all 10 of the dimensions measured. The

explanation is of course that every human being is unique, bodily dimensions vary quite widely both in terms of absolute size and in proportion to each other. In other words, the average person is rather unique.

Nevertheless it is possible to define populations that have characteristics that are similar to or different from other populations. Generally speaking adults are taller than children, so age is one criterion we can use to define different user groups. Another is gender: men tend to be taller than women, although some women are of course taller than some men.

Physical condition is another way of looking at systematic variation between different populations. Pregnancy and obesity are conditions that have obvious implications for size and shape. Disabilities that limit movement or that affect physical size and shape may be another way of defining user populations usefully. Factors such as age, size, occupation, leisure interests and personal values may all be relevant characteristics in defining the user population. So when we talk about the typical user we need to make sure that we actually have a truly representative range of typical users in mind.

One common way of defining the range of a user population is the so-called method of extremes. Using this method, sample users are selected to represent the extremes of the user population plus one or two intermediate values.

In a study to establish recommended kitchen work surface heights, three groups of sample female users were selected for the experiments

The idea of a percentile is quite straightforward. It is that proportion of the population under consideration with a dimension at or less than a given value. So, for example, if the 95th percentile for the standing height of a population is 1795 mm, then 95 per cent of that population are 1795 mm or shorter.

This is shown graphically. The horizontal axis shows what percentage of the total population reach a particular height and the vertical axis represents a range of different standing heights. From this figure you can see that 95 per cent of this particular population are 1795 mm or less tall, whereas only 5 per cent are 1605 mm or less, and 50 per cent are 1700 mm or less. Therefore, someone with a standing height of 1605 mm is at the 5th percentile, someone 1700 mm tall is on the 50th percentile and someone 1795 mm tall is at the 95th percentile of this population.

Who is the average user?

The average user is just a formula obtained from the characteristics of our real users. Since it is not possible to take into account the needs of all our users, we design according to the needs of a “typical” user that represents them.

Obviously, these average users cannot represent ‘extreme’ users, those who are further away from them because of some of their characteristics. But this is not important because it is assumed they are just a minority.

However, we need to consider two drawbacks:

1. The average user is artificial

The average user is created from the combination of all users. What we get is, in fact, a completely different user. None of our users is like the average user. Therefore, when designing for that artificial individual we create something that doesn’t fit anyone’s needs.

2. The average user is static

The average user is the representation of a moment, motionless. However, real users change constantly, reaching different positions, assuming different roles with different characteristics. In fact, we all are extreme users countless times in our lives. When designing for a static individual, we’re creating something that satisfies nobody.

Because of these two factors, average user-centered design generates two types of dysfunctions:

Dysfunction 1. The usability decreases progressively as we move away from the average user.

The degree of usability (understood here as the correct adaptation of a service or product to the needs of the user) is directly proportional to the degree of similarity between the average user and the real user (the similarity is established from that attribute that is most relevant in a given context).

Thus, the larger the difference between a person and the average user, the lower the usability of the service or product. Of course, considering that the average user is a fiction, it is impossible to achieve a 100% of usability.

Dysfunction 2. Usability drops sharply for those users who do not reach the average user’s threshold. ​ ​

In other contexts, people need to reach a minimum threshold, usually determined by the average user, to use correctly a service or product. Thus, the degree of usability for those users who do not reach this threshold will be close to 0%.

The solution to these two dysfunctions lies in designing for the extremes:

Solution 1. Responsive business model

In a situation marked by the dysfunction 1, the solution lies in designing services and products that adapts (responsive) to the needs of different customer profiles or can be personalized, without having to create different products or services.

Solution 2. Least common usability threshold

In a situation marked by dysfunction 2, the solution lies in using the least threshold of usability shared by all users, as long as the product or service maintain its consistency.

A typical example would be the page load speed. The average user-centered design created sites with a good performance if the real user had a connection speed equal or higher than the average user. However, this creates dysfunctions in all those cases where this minimum speed is not reached. This situation has worsened with the emergence of mobile devices with Internet access.

The design for the extremes solves this dysfunction by using the least common usability threshold, i.e. the connection speed of mobile devices. The reason is simple: if you can solve this problem for mobile users, you have improved the usability for everyone.

Inclusive design

Inclusive design (or universal design) means designing products so that they can be used easily by as many people as wish to do so. This may sound an obvious goal, but the fact is that many people – some estimates suggest as many as one-fifth of all adults – have difficulty carrying out ordinary tasks with everyday products. Many elderly and ​ ​ disabled people cannot carry out – certainly with any ease or dignity – the range of everyday tasks that others take for granted. They are forced to choose products from a limited range that may suit them, and may also have to adapt products themselves, or buy expensive attachments to compensate for a product's inadequate design.

In considering the iterative user-centred design process outlined in the previous section, it should be clear that including people with disabilities and older people amongst the evaluators can be part of this process, and that target levels for accessibility can play an important role in the overall process. This is in contrast with many writers, who only include a consideration of disabled and older people at the end of the design and development process. However, it is clear that if the full range of potential users is considered from the beginning of the process, the overhead of considering the needs of disabled and older users is minimal – it is simply part of the overall design process. On the other hand, if one designs only for young, mainstream users and then attempts to expand the process for disabled and older users at a late stage, one is contradicting the user-centred design process and it is very likely that complex and expensive retro-fitted solutions will be necessary for these users. In some cases, it is impossible to retro-fit a solution to include the needs of particular disabled and older users, and the design process really needs to be started again.

The picture of a radio with do-it-yourself adaptations made for an elderly user with poor eyesight and arthritis. Some buttons are covered to avoid accidental pressing, which would lose the preset channel, while others have high-visibility stick-on covers. Instructions for retuning the radio presets are attached for carers in case the user does press the wrong buttons. The end of the aerial is padded to avoid accidental eye damage to the user.

Recall that the Good Grips vegetable peeler originated by observing the difficulties of someone with arthritis using a conventional peeler. Many producer companies have begun to realise that excluding major sections of the population of potential users of their products is not only unjust but also bad business sense. As the populations in industrialised countries continue to age, there is a growing commercial case for inclusive design. By 2015, nearly twenty percent of the population of Europe will be aged 65 or over. They will be more active, and have more purchasing power, than previous elderly generations, and will be less tolerant of product designs that ‘exclude’ them.

Most commonly this pyramid is approached from the bottom up. This creates mainstream solutions with the possibility of reaching a large market share from the start. The problem with this solution however is that consideration often ends after catering for the needs of the able-bodied and general public. The number of people that are being included additionally moving up the pyramid diminishes and most commonly marketers interpret that as a sign of slowdown in product success resulting in the stop of further consideration and development. Creating solutions usable to some of the upper parts of the pyramid is often coincidental rather than considered.

Approaching the pyramid from the top down is the key for creating truly inclusive design solutions. By catering for the requirements of those most in need of consideration first, products and services can - if this approach is well executed – become available for user groups outside the original target market and the general public.

Evaluating the user pyramid further it is very interesting to find out who the different parts consist of. The minor disabilities group could be those with slight visual impairments, learning difficulties or people affected by temporary illness. Reduced strength and mobility might be caused by the effects of pregnancy, an accident resulting in a broken bone or progressing age. Severe disabilities don’t have to be present from birth; they could be the result of an infection or accident amongst other reasons.

Regardless of the reason for the impairments users face, it is a fact that every person in their life requires education, medical assistance, transportation or other means that in some way or another give them special needs. The dynamics within the user pyramid are therefore constantly shifting and people who are completely able-bodied might find themselves confronted with difficulties moving them into a different category one day. This proves that inclusive design is not about generating solutions for ‘minorities’ or niche markets after all – but design for as wide of an audience as possible.