Usability I believe that good usability is paramount.
Good usability is what reduces the number of errors a user of a given system may make. Good usability is an expression of the
satisfaction the user will experience when she or he is using a well designed system to do what they have to do. Good usability is what gets the job done, effectively and efficiently.
Formally, usability is defined as the
“extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use” (authors emphasis) (ISO9241-11, 1998; ISO9241-210, 2009, p. 3; ISO13407, 1999, p.
1),
a definition Karlsson (2000) recommends as the most appropriate, even though more comprehensive views are available.
In more everyday terms, Krug (2006) describes usability as
“really just […] making sure that something works well: that a person of average (or even below average) ability and
experience can use the thing – whether it’s a Web site, a fighter jet, or a revolving door – for its intended purpose without getting hopelessly frustrated” (Krug, 2006, p. 5).
Rubin suggests that usability consists of one or more of four different attributes, including Usefulness, Effectiveness, Learnability and Attitude(1994, pp. 18-19), and Nielsen refines this suggestion, and defines usability as having five components: Learnability, Efficiency, Memorability, [low number of] Errors and Satisfaction (1993, p. 26).
For the purpose of this thesis, I have chosen to define usability as a union of the above, i.e. as ‘the extent to which a product or process can be used by specified users to achieve specified goals with
effectiveness, efficiency, ease of learning and satisfaction in a specified context of use’.
Designing for Usability
Usability requires a conscious effort. “You can only design your way to usability”, Gulliksen, Boivie and Göransson (2006, p. 592) notes, and to do so, a method, or a number of methods, applied for the
purpose of designing for usability, are required.
According to Quesenbery (2005), ISO 9241-210 and ISO 13407 ((ISO9241-210, 2009; ISO13407, 1999))3 describes the primary, or universally accepted and applicable, methods for designing for usability.
In particular, she notes that
“A brief examination of presentations on user centered design at industry conferences easily shows the influence of this standard [ISO 13407]. Whether it is mentioned by name, or whether the process described simply mirrors the one in the standard, it is clear that the industry has embraced at least the principles and broad outline of this standard” (Quesenbery, 2005, p. 452).
In practical terms, ISO 9241-210 (2009) defines the meaning of UCD – or Human Centered Design (HCD), as the standard chooses to name it – as
“an approach to interactive system development that aims to make systems usable by focusing on the users, their needs and requirements, and by applying human factors, ergonomics and usability knowledge and techniques” (p. vi).
A few words about the naming of the discipline might be in place. At some stage, computer vendors came to the realization that users was more than an inconvenience, and introduced the term ‘user friendly’, but the term is not really appropriate: Users do not need
‘friendly’ machines (Nielsen, 1993), but machines that will support their work, as discussed above, along the axes of effectiveness, efficiency and satisfaction (ISO9241-210, 2009; ISO13407, 1999), which is congruent with the goal of the human factors science with respect to
3. It should be mentioned that ISO 9241-210 (1998) is a revision of ISO 13407 (1999), replacing the latter.
systems integration (Wickens, Lee, Liu, & Gordon Becker, 2004).
Because of the shortcoming of the ‘user friendliness’ term,
“user interface professionals have tended to use other terms…the field itself known under names like CHI (computer-human interaction), HCI (human-computer interaction, which is preferred by some who like ‘putting the humans first’ even if only done symbolically), UCD (user-centered design)…HF (Human factors)…” (Nielsen, 1993),
but no matter the term, for the human factors specialist, the central focus of design revolves round the importance of the user (Wickens, et al., 2004), irrespectively of whether the expression used is
‘human’ or ‘user’.
As such, the two standards mentioned here establishes UCD as one of the methods to achieve usability, and furthermore provides the main methodology: The core of UCD is to focus an iterative design process, conducted by a multidisciplinary team (ISO9241-210, 2009;
ISO13407, 1999), on the use and users of the subject under
consideration – usually a system, device or instrument of some sort. The focus on the users includes the due consideration of their characteristics, needs and requirements in the context of their work and working environment, and the UCD process is designed to maintain this consideration, through the direct and continuous involvement of the end-users, as a minimum for the duration of the development process, or better, throughout the entire product life-cycle (Nielsen, 1993).
Research Focus
As outlined in the Prologue, one can ask: ‘Is User Centered Design usable’?
My research is pursuing this issue as the central, ultimate research subject, using the definition of usability provided above, i.e.
whether or not user centered design is effective, efficient, easy to learn and satisfactory to apply.
Since the concept of usability itself is context dependent (ISO9241-210, 2009; ISO13407, 1999), so is the research question.
Karlsson (2000) notes that “The use situation as a whole must addressed and understood before any recommendations can be made as to the design” (2000, p. 54), which stresses the necessity of considering the
intended context-of-use of user centered design. ISO 9241-210 (2009) provides an insight in this respect, by stating that
“There is a substantial body of human factors, ergonomics and usability knowledge about how human-centred design can be organized and used effectively”,
and continuing that
“this part of ISO 9241 [210] aims to make this information available to help those responsible for managing hardware and software design and redesign processes to identify and plan effective and timely human-centred design activities” ISO 9241(2009, p. iv).
In plainer terms, the statement conveys the impression that the context-of-use of user centered design is industrial application within the IT community, but this issue is never spelled out entirely in ISO 9241-210 (2009), even though the implied understanding is elaborated in a later section:
“The information in this part of ISO 9241 [210] is intended for use by those responsible for planning and managing projects that design and develop interactive systems” (2009, p. 1).
Research Question: Definition
Utilizing the above, substituting the term ‘usability’ with the wording from the definition, and adding the context-of-use explicitly, my research question is defined as
‘Is the application of UCD according to ISO 9241-210 effective, efficient, satisfactory and easy to learn for those responsible for managing hardware and software design and redesign processes?’
Before moving on, I would like to make one thing very plain: This thesis is not on a mission to raise criticism towards what I consider to be a most important and well prepared
international standard, and ISO 9241-210 (2009) is not the target, but rather an invaluable reference on user centered design. The
process the standard describes and explains is however what is being scrutinized.
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