Theory of User Engineering

Masaaki Kurosu

• Publisher: CRC Press
• Year: 2016
• ISBN:
  9781315355672
• Edition: 1
• Topic: Ciencia de la computación
• Subtopic: Interacción persona-computadora

This book outlines the new concept of user engineering and covers the diversity of users, along with the business process that includes the design and the user's experience processes. Although the concept of user experience (UX) has become popular, the definition and the methodology are still ambiguous. User engineering is similar to the user-centered design, but differs in that its scope is not limited to the design process but concerns the whole manufacturing process and the whole usage process, i.e., the whole lifecycle of an artifact. User's perspective is strongly emphasized in this book, hence, its stance is far from that of the marketing approach that usually fails to notice the life and experiences of users after the purchase of an artifact as consumers.

Theory of User Engineering differentiates between the quality in design and the quality in use, and the objective quality characteristics and the subjective quality characteristics. In addition to the user research using ethnographic methods, the author introduces a new approach based on the artifact evolution theory that can be adopted in the planning stage.

1 What Is User Engineering?

User engineering is a set of concepts and methods for improving the quality of life of users. Many concepts and methods have been inherited from usability engineering and user experience (UX) design. But the difference with user engineering lies in its stance:

1. Compared to usability engineering, its scope is wider and includes other quality characteristics such as reliability, safety, and even beauty and cuteness.
2. Compared to UX design that is currently a bit more oriented toward marketing and designing an attractive artifact for consumers to buy, it focuses on user satisfaction and the significance of artifacts.

1.1 WHO ARE THE USERS?

Simply speaking, users are those who use the artifact. But a bit more explanation is necessary in its relation to consumers. The marketing approach targets consumers and puts emphasis on figuring out their motivation to purchase the artifact. Generally, it is the goal of marketing that consumers should buy the artifact. Of course, marketing emphasizes the feedback for the next purchase and in this sense puts emphasis on the use of the artifact. That is, the marketing approach also looks after the user’s response. But its main point is on the purchase of the artifact.

Consumers who purchase an artifact will become users. Typically, they start to use it by trial-and-error or by reading the operator’s manual if there is one. Then users get used to the artifact and learn more about it and gradually grow from novice users to experts. After long-term usage, some event will occur in a positive sense or a negative sense. And when the performance of the artifact degrades or there is any malfunctioning, users will stop using it.

Hence, all through the artifact lifecycle, that is, before, during, and after the purchase, consumers change into users and obtain various kinds of information about the artifact and use the artifact itself. But, user engineering mainly deals with the phase of the user. It also deals with the phase of consumer because it is also the phase of preuser.

1.1.1 ISO/IEC 25010:2011

When users start using an artifact, ISO/IEC 25010 proposes a list regarding the concept of users. Figure 1.1 shows a revised version of the definition of users in the standard. At the top level, direct users who directly interact with the system are different from indirect users who do not interact with the system but use the output of the system. Take for example the case of an MRI at a hospital; the medical doctors who receive the resulting image are indirect users.

FIGURE 1.1 Classification of users. (Adapted from ISO/IEC 25010.)

Direct users are, then, classified as the primary users who interact with the system for the achievement of a primary goal, or the secondary users who provide the support to the system. In the case of an MRI, the maintenance personnel and manager of the inspection department are examples of secondary users.

The classification of ISO/IEC 25010 is given at these two layers. But if we consider the case of an MRI, there are MRI operators and patients as primary users. So I added a third layer by distinguishing active primary users, who actively interact with the system, and passive primary users, who passively interact with the system. In the case of an MRI, operators are active primary users and patients are passive primary users.

But passive primary users do not always exist. If we consider the projector used in a classroom, active primary users are teachers who use the projector for teaching the lesson by showing PowerPoint slides to students. But students are not passive primary users but are indirect users who look at the slide images on the screen and get information from them.

For active primary users, the objective quality characteristics, including the usability (especially the ease of operation and the ease of understanding), are quite important. But for passive primary users, the exterior design of the MRI, for example, should give subjective quality characteristics such as the sense of relief for the comfort during the examination.

For secondary users, the cost, ease of maintenance, and reliability are important, and for indirect users, the ease of understanding the output is important. As such, different aspects of quality characteristics are important for different types of users. Generally speaking, there is a tendency to use the word user for meaning the active primary user. But at the same time, it must be remembered that there are other types of users and the artifact should be designed considering all types of users as much as possible.

In the example of the projector used in the classroom, the (active) primary user is, of course, the teacher who operates the projector. The secondary user is the personnel of the school who do the maintenance work, for example, replacing the bulb in the projector. Indirect users, in this case, are students who watch the projected slide images and ask questions on the information contained on the slides.

1.1.2 STAKEHOLDERS AND USERS

From Figure 1.1, one might suggest that users might be the same as stakeholders. But stakeholders of an artifact will include those people who belong to the industry including manufacturers and service providers as well as those who are outside the industry. Thus, user-centered design (UCD) is an outside-in approach, whereas marketing is an inside-out approach. User engineering focuses on the outside and takes an outside-in approach.

1.1.3 USERS AND CONSUMERS

Consumer is the term that is frequently used by marketing people. It is quite natural that they use this word because the word marketing comes from the word market, and the market is the place where money and the product are exchanged between the consumer and the merchant. But, it should be noted that the activity at the market will end when the exchange is completed. After the purchase, the consumer will go back to their ordinary life to become the user.

The end of marketing activity is the time when users start their activity. More precisely, former consumers will become users and start using the product they purchased. As a natural result, marketing people are not much interested in the life of users and problems that users may face, but are focused more on how to sell products to consumers. Hence, they are not much concerned with usability. This is because usability is difficult to evaluate at the marketplace. From this viewpoint, it is a bit strange that marketing people use the term UX. UX is the experience of users and marketing people are not concerned much about the life and the problems among users in their ordinary life. It is suspected that marketing people are using the term UX in the sense of “anticipated UX” that is not yet confirmed by the real experience among users. Though it is true that the anticipated UX can be a part of the total scope of the UX, the hit ratio of the anticipation is usually not high and we will have to survey the actual UX in the actual context of use.

1.1.4 INTENDED USERS

Sometimes, the term intended user, or targeted user, is used among developers. It is a common habit of marketing people to specify who the main user is. The persona method is frequently used for the purpose of sharing the image of intended users among stakeholders. This approach is effective for curtailing the development cost by focusing on the limited number of specific users so that the specification can be easily decided.

But this is a tricky strategy. Strictly limiting the range of users only to the intended users will result in the loss of chance for the artifact to be used by a wide range of people. Hence, the adequate strategy is to think of the loose bell-shaped user population where the center of the distribution is the targeted user. This strategy will lead to a compromise with the notion of universal design that will be discussed in the next section.

1.2 UNIVERSAL DESIGN AND ACCESSIBILITY

Until the 1990s, it was common to implicitly assume that the user of any product or system is a male in his 30s with a certain level of technological skill and intelligence. But it actually was the image of the engineers themselves. As a natural result, there occurred the discrepancy between the actual user and the assumed user image. Furthermore, there were complaints among users that the artifact they purchased did not fit them. Many of the real users are not males in their 30s with a certain level of skill and intelligence.

What changed this situation was the advent of the concept of universal design (Lidwell et al. 1997). Universal design is defined by Mace (2016) as “the design of products and environments to be usable by all people, to the greatest extent possible, without the need for adaptation or specialized design.” He also wrote, “The intent of universal design is to simplify life for everyone by making products, communications, and the built environment more usable by as many people as possible at little or no extra cost. Universal design benefits people of all ages and abilities.”

In this sense, universal design aims at the whole variety of users, including sex, age, disability, culture, and language. A possible list of such characteristics will be explained in the next section. But because many of those who started to work in the field of universal design also worked in the field of accessibility, the activity of universal design frequently puts emphasis on disabled and senior people rather than the whole range of diversity. According to the definition in ISO/IEC 25010, accessibility is “to what extent does the system need to be effective, efficient, risk free and satisfying to use for people with disabilities.” In this sense, accessibility is the usability for the disabled (refer to Chapter 2 for the definition of usability).

User engineering focuses on the possible widest range of people in the same sense of genuine universal design.

1.3 DIVERSITY OF USERS

There are three different aspects on the diversity of users: (1) characteristics, (2) inclinations, and (3) situation and environment (Figure 1.2).

1.3.1 CHARACTERISTICS

Characteristics belong to users themselves and represent the differences among users. They include such physical differences as age, sex and gender, disability, temporary situation, physical traits, language, knowledge and skill.

FIGURE 1.2 Three aspects of diversity among users.

1.3.1.1 Age

Age is a characteristic along the time dimension. There are three different aspects for a person in terms of the time dimension—age group, cohort, and same time period—as shown in Figure 1.3.

Age groups are those of the same age. An example is the definition of the senior person, those equal to or older than 65 years, according to the World Health Organization (WHO). Physical strength, physiological functioning, and psychological ability will show a decreasing tendency, especially after 60 to 65 years of age. This tendency is almost the same as it was in the 1900s and 2000s and maybe later in the 2050s, though there have been some positive changes due to improvements in living environment and medical science. Regarding the use of ICT (information and communications technology) products and systems, people show a similar set of changes as they grow older: presbyopia makes them need to see larger letters and use reading glasses, the loss of hearing ability makes them need louder auditory signals and a clear pronunciation or a hearing aid, slower reaction time requires longer waiting time, lower visual search ability requires a simple visual interface, and so on. On the contrary, children will have to be given special care on the user interface: for example, messages from the system should use simple and plain linguistic expressions so that they can understand the meaning.

A cohort is a group of people who were born during the same era and experience similar social and historical events. A generation, such as the “digital native,” is an example of a cohort. Cohorts who were born before the time of ICT development generally show poor literacy for using such devices and systems.

Finally, all people are living in the same period of time. Those who are living in the 2010s, whatever their age, are provided the chance of using the smartphone, a PC, and the Internet. And we’ll have to be careful to note the difference of age groups and cohorts in terms of background skill and knowledge.

FIGURE 1.3 Three temporal aspects of a person.

1.3.1.2 Sex and Gender

Almost half of people are male and the other half are female. Sex is a biological concept and gender is a sociological concept.

Regarding sex, ther...