Formative evaluations do just this. These quick, qualitative tests are conducted during the design process, generally during the Refinement phase. When effectively devised and moderated, a formative evaluation opens a window to the user’s mind, allowing the designers to see how their target audience responds to the information and tools they’ve provided to help them accomplish their tasks.
Though summative evaluations have their uses, they are product- and program-management activities conducted to inform product lifecycle planning. They can be useful “disaster checks” during development, but the costs of changes at this point — in time, money, and morale — can be high. Formative evaluations are conducted in the service of design, during the design process.
Conducting formative usability tests
There are a wide variety of perspectives on how to conduct and interpret usability tests. Unfortunately, we’ve found that many of these approaches either presume to replace active design decision making, or are overly quantitative, resulting in non-actionable data about things like “time to task.” A good reference for usability testing methods that we’ve found to be compatible with Goal-Directed interaction
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design methods is Carolyn Snyder’s Paper Prototyping. It doesn’t discuss every testing method or the relationship between testing and design, but it covers the fundamentals well and provides some relatively easy-to-use techniques for usability testing.
In brief, we’ve found the following to be essential components to successful formative usability tests:
Test late enough in the process that there is a substantially concrete design to test, and early enough to allow adjustments in the design and implementation
Test tasks and aspects of the user experience appropriate to the product at hand
Recruit participants from the target population, using your personas as a guide
Ask participants to perform explicitly defined tasks while thinking aloud
Have participants interact directly with a low-tech prototype (except when testing specialized hardware where a paper prototype can’t reflect nuanced interactions)
Moderate the sessions to identify issues and explore their causes
Minimize bias by using a moderator who has not previously been involved in the project
Focus on participant behaviors and their rationale
Debrief with observers after tests are conducted to identify the reasons behind observed issues
Involve designers throughout the study process
Designer involvement in usability studies
Misunderstanding between the designer and the user is a common cause of usability problems. Personas help designers understand their users’ goals, needs, and points of view, creating a foundation for effective communication. A usability study, by opening another window on the user’s mind, allows designers to see how their verbal, visual, and behavioral messages are received, and to learn what users intend when interacting with the designed affordances.
Designers (or, more broadly, design decision makers) are the primary consumers of usability study findings. Though few designers can moderate a session with sufficient neutrality, their involvement in the study planning, direct observation of study sessions, and participation in the analysis and problem-solving sessions are critical to a study’s success. We’ve found it important to involve designers in the following ways:
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Planning the study to focus on important questions about the design
Using personas and their attributes to define recruiting criteria
Using scenarios to develop user tasks
Observing the test sessions
Collaboratively analyzing study findings
Notes
1. Schumann et al.
2. Cooper, 1999
3. Shneiderman, 1998
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Part
II
Designing Behavior
and Form
Chapter 8
Chapter 12
Synthesizing Good Design:
Designing Good Behavior
Principles and Patterns
Chapter 13
Chapter 9
Metaphors, Idioms, and
Platform and Posture
Affordances
Chapter 10
Chapter 14
Orchestration and Flow
Visual Interface Design
Chapter 11
Eliminating Excise
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8
Synthesizing Good Design:
Principles and Patterns
In the last four chapters, we discussed how to appropriately sequence the decisions to define and design a desirable and effective product. But how do we make these decisions? What makes a design solution good? As we’ve already discussed, a solution’s ability to meet the goals and needs of users while also accommodating business goals and technical constraints is one measure of design quality. But are there recognizable attributes of a good solution that enable it to accomplish this successfully? Can we generalize common solutions to apply to similar problems?
Are there universally applicable features that a design must possess to make it a
“good” design?
The answers to these questions lie in the use of interaction design principles and patterns. Design principles are guidelines for design of useful and desirable products, systems, and services, as well as guidelines for the successful and ethical practice of design. Design patterns are exemplary, generalizable solutions to specific classes of design problems.
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Interaction Design Principles
Interaction design principles are generally applicable guidelines that address issues of behavior, form, and content. They encourage the design of product behaviors that support the needs and goals of users, and create positive experiences with the products we design. These principles are, in effect, a set of rules based upon our values as designers and our experiences in trying to live up to those values. At the core of these values is the notion that technology should serve human intelligence and imagination (rather than the opposite), and that people’s experiences with technology should be structured in accordance with their abilities of perception, cognition, and movement.
Principles are applied throughout the design process, helping us to translate tasks and requirements that arise from scenarios into formalized structures and behaviors in the interface.
Principles operate at different levels of detail
Design principles operate at several levels of granularity, ranging from the general practice of interaction design down to the specifics of interface design. The lines between these categories are fuzzy, to say the least, but interaction design principles can be generally thought of as falling into the following categories:
Design values describe imperatives for the effective and ethical practice of design. These principles inform and motivate lower-level principles and are discussed later in this chapter.
Conceptual principles help define what a product is and how it fits into the broad context of use required by its users. Chapters 3, 9, and 10 discuss conceptual-level design principles.
Behavioral principles describe how a product should behave, in general, and in specific situations. Chapters 8–20 discuss general behavior-level principles.
Interface-level principles describe effective strategies for the visual communication of behavior and information. Principles in Chapters 13 and 14 are focused on this level of interaction design, which is als
o touched upon in many chapters in Parts II and III.
Most interaction and visual design principles are cross-platform, although some platforms, such as mobile devices and embedded systems, require special consideration because of constraints imposed by factors like screen size, input method, and use context.
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Behavioral and interface-level
principles minimize work
One of the primary purposes principles serve is to optimize the experience of the user when she engages with a product. In the case of productivity tools and other non-entertainment-oriented products, this optimization means minimizing work.
Types of work to be minimized include:
Cognitive work — Comprehension of product behaviors, as well as text and organizational structures
Memory work — Recall of product behaviors, command vectors, passwords, names and locations of data objects and controls, and other relationships between objects
Visual work — Figuring out where the eye should start on a screen, finding one object among many, decoding layouts, and differentiating among visually coded interface elements (such as list items with different colors)
Physical work — Keystrokes, mouse movements, gestures (click, drag, double-click), switching between input modes, and number of clicks required to navigate Most of the principles in this book attempt to minimize work ,while providing greater levels of feedback and contextually useful information to the user.
It should also be mentioned that certain kinds of entertainment products (such as games) are able to engage as a result of requiring users to do just the right amount of a certain kind of work and rewarding them for doing so. Recall the Tamagotchi craze from the late 1990s: People became addicted to the work required to take care of their handheld virtual pet. Of course, too much work or too little reward would turn the game into a chore. This kind of interaction design requires a fine touch.
Design Values
Principles are rules that govern action, and are typically based at their core on a set of values and beliefs. The following set of values was developed by Robert Reimann, Hugh Dubberly, Kim Goodwin, David Fore, and Jonathan Korman to apply to any design discipline that aims to serve the needs of humans.
Designers should create design solutions that are:
Ethical [considerate, helpful]
Do no harm
Improve human situations
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Purposeful [useful, usable]
Help users achieve their goals and aspirations
Accommodate user contexts and capacities
Pragmatic [viable, feasible]
Help commissioning organizations achieve their goals
Accommodate business and technical requirements
Elegant [efficient, artful, affective]
Represent the simplest complete solution
Possess internal (self-revealing, understandable) coherence
Appropriately accommodate and stimulate cognition and emotion
The following subsections explore each of these values.
Ethical interaction design
Interaction designers are faced with ethical questions when they are asked to design a system that has fundamental effects on the lives of people. These may be direct effects on users of a product, or second-order effects on other people whose lives the product touches in some way. This can become a particular issue for interaction designers because, unlike graphic designers, the product of their design work is not simply the persuasive communication of a policy or the marketing of a product. It is, in fact, the means of executing policy or the creation of a product itself. In a nutshell, interactive products do things, and as designers, we must be sure that the results of our labor do good things. It is relatively straightforward to design a product that does well by its users, but the effect that product has on others is sometimes more difficult to calculate.
Do no harm
Products shouldn’t harm anyone, or given the complexities of life in the real world, should, at the very least, minimize harm. Possible types of harm that interactive systems could be a party to include:
Interpersonal harm (loss of dignity, insult, humiliation)
Psychological harm (confusion, discomfort, frustration, coercion, boredom)
Physical harm (pain, injury, deprivation, death, compromised safety)
Environmental harm (pollution, elimination of biodiversity)
Social and societal harm (exploitation, creation, or perpetuation of injustice)
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Avoiding the first two types of harm requires a deep understanding of the user audience, as well as buy-in from stakeholders that these issues are within a scope that can be addressed by the project. Many of the concepts discussed in Parts II and III can help designers craft solutions that support human intelligence and emotions. Avoiding physical harm requires a solid understanding of ergonomic principles and appropriate use of interface elements so as to minimize work. See Part III for guidance on this. Obviously, the last two types of harm are not issues for most products, but you can surely imagine some examples that are relevant, such as the control system for an offshore oil rig or an electronic voting system.
Improve human situations
Not doing harm is, of course, not sufficient for a truly ethical design; it should be improving things as well. Some types of situations that interactive systems might improve broadly include:
Increasing understanding (individual, social, cultural)
Increasing efficiency/effectiveness of individuals and groups
Improving communication between individuals and groups
Reducing sociocultural tensions between individuals and groups
Improving equity (financial, social, legal)
Balancing cultural diversity with social cohesion
Designers should always keep such broad issues at the back of their minds as they engage in new design projects. Opportunities to do good should always be considered, even if they are slightly outside the box.
Purposeful interaction design
The primary theme of this book is purposeful design based on an understanding of user goals and motivations. If nothing else, the Goal-Directed process described in the chapters of Part I should help you to achieve purposeful design. Part of purposeful-ness, however, is not only understanding users’ goals but also understanding their limitations. User research and personas serve well in this regard. The behavior patterns you observe and communicate should describe your users’ strengths as well as their weaknesses and blind spots. Goal-Directed Design helps designers to create products that support users where they are weak and empower them where they are strong.
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Pragmatic interaction design
Design specifications that gather dust on a shelf are of no use to anyone: A design must get built to be of value. Once built, it needs to be deployed in the world. And once deployed, it needs to provide benefits to its owners. It is critical that business goals and technical issues and requirements be taken into account in the course of design. This doesn’t imply that designers necessarily need to take everything they are told by their stakeholders and programmers at face value: There must be an active dialog among the business, engineering, and design groups about where there are firm boundaries and what areas of the product definition are flexible. Programmers often state that a proposed design is impossible when what they mean is that it is impossible given the current schedule. Marketing organizations may create business plans based upon aggregated and stat
istical data without fully understanding how individual users and customers are likely to behave. Designers, who have gathered detailed, qualitative research on users, may have insight into the business model from a unique perspective. Design works best when there is a relationship of mutual trust and respect among Design, Business, and Engineering.
Elegant interaction design
Elegance is defined in the dictionary as both “gracefulness and restrained beauty of style” and “scientific precision, neatness, and simplicity.” We believe that elegance in design, or at least interaction design, incorporates both of these ideals.
Represent the simplest complete solution
One of the classic elements of good design is economy of form: using less to accomplish more. In interface design, this means using only the screens and widgets necessary to accomplish the task. This economy extends to behavior: a simple set of tools for the user that allows him to accomplish great things. In visual design, this means using the smallest number of visual distinctions that clearly conveys the desired meaning. Less is more in good design, and designers should endeavor to solve design problems with the fewest additions of form and behavior, in conformance to the mental models of your personas. This concept is well known to programmers, who recognize that better algorithms are clearer and shorter.
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