According to Association for Computing Machinery Special Interest Group on Computer-Human Interaction (ACM SIGCHI), “HCI is a discipline concerned with the design,
evaluation and implementation of interactive computing systems for human use and with the study of major phenomena surrounding them” [56].
HCI is multidisciplinary itself. It concerns ergonomics, informatics, industrial engineering, psychology, social sciences, cognitive science, graphic design, and so forth. From HCI-relevant resources, we can find and learn basic principles, theories, and established methods from these disciplines that are employed in HCI research field.
In this section, I will describe the two most relevant topics to this research.
2.2.1 Usability
As I wrote in 1.2, ISO13407 [23] defines usability7 as the “extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and
7 There are different definitions of usability. For example, Sharp et al. [57] sharp states that “usability is generally regarded as ensuring that interactive products are easy to learn, effective to use, and enjoyable from user’s perspective.” (p. 20) and they elaborate the usability goals as “effective to use (effectiveness)”, “efficient to use (efficiency)”, “safe to use (safety)”, “having good utility (utility)”, “easy to learn (learnability)”, and “easy to remember how to use (memorability)”. In this dissertation however, I follow the definition of ISO13407 as I stated in 1.2.
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satisfaction in a specified context of use [ISO 9241-11: 1998, definition 3.1]”. Usability matters not only for users’ acceptance or preference of a product but also for proper use of a product and consequence of using a product [58]. Therefore, usability is an essential quality factor with regard to a personal-use based mHealth technology for self-management of T2DM.
Goals of usability evaluation can vary depending on the purpose; for example, comparison of several products to make a choice, evaluation of revised design, comparison by different types of users such as novice users and experienced users, finding problems that affect usability, and so forth. Effectiveness is defined as the “accuracy and completeness with which users achieve specified goals” and efficiency is defined as “resources expended in relation to the accuracy and completeness with which users achieve goals” [23]. Thus they can be
objectively and quantitatively measured by conducting usability testing of a product regarding certain tasks with certain goals. Concrete measure is decided up to the usability goals and purposes of an evaluation. On the other hand, satisfaction is defined as “freedom from discomfort, and positive attitudes to the use of the product” [23]. Therefore, measuring
satisfaction requires self-reporting by users. Satisfaction could be asked either or both per task, per function or / and as overall perception of the whole product. Often times, semantic
differential methods, Likert-scale and preference of compared products are used as well as established questionnaires such as; System Usability Scale (SUS) [59], AttrakDiff™ [60] and those discussed in [58] or listed in Common Industry Format for Usability Test Reports [61]8. To achieve high usability, it is essential that a product is easy to use. Krug explains ease of use as “self-explanatory, obvious and self-evident regarding what it is and how to use it” [62].
Series of design principles and guidelines are proposed to achieve ease of use, but there are a lot of similarities [63]. Design principles are also used for evaluation of usability, and when used in evaluation they are called heuristics [57]. Nielsen conducted a factor analysis to synthesize different usability heuristics and revealed that the identified top 10 heuristics can explain 95% of serious usability problems in total [64].
As its definition describes, usability of a product is determined both by the three factors and by relationship between those factors and context of use. “Context of use” is defined as “users, tasks, equipment (hardware, software and materials), and the physical and social
environments in which a product is used” [23]. This implies that there are lots of factors that would influence usability. Considerable difference in context of use between handheld terminals and desktop computers called for: research on usability factors specific to mobile terminals with different size of screen and input methods from desktop computers [65–71];
usability testing in field settings [72–74]; and development of new heuristics [75], satisfaction measure [76], check list [77] and cognitive model [78] that are specific to mobile9.
In addition, technology development of handheld devices is so rapid that specification changes dramatically within a few years. By following such changes, factors determining usability need to be revisited for investigation. This is argued by Fling in his book “Mobile Design and Development” issued in 2009 [79], saying like: “Don’t trust any report, fact, or
8 Here I refer to the Common Industry Format version 2.0 published at http://zing.ncsl.nist.gov/iusr/ but cite ISO standard ISO/IEC 25062:2006 because the format is not anymore available at the website of National Institute of Standards and Technology.
9 Tremendous amount of research works can be found in relevant journals and conferences, but I listed up ones whose findings are relevant to this dissertation.
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figure that is more than a year or two old. It is most likely wrong (p. 61)”, “Don’t try to simply apply the same rationale to your mobile strategy as you would your web or print strategy (p. 67)” and “Don’t forget to innovate. Try new things, be bold, and don’t be afraid to fail (p. 61)”. Nevertheless, very general principles still need to be consulted at designing and evaluation before user testing. For example, “keep it simple” remains important in design for mobile device, as Fling also provides relevant principles in the same book [79].
ISO13407 [23] also defines the Human-Centred Design (HCD) process for interactive system.
UCD yields huge benefit in terms of: efficiency, satisfaction, productivity (or effectiveness) by using the system, and quality of the developed system. Careful consideration on selection of the potential users and degree of involvement in design process is the first key issue, because user-involvement must be as effective as possible. The second key issue would be how early and how often user could be involved. One of the characteristics of human-centered approach that ISO13407 defines is “the active involvement of users and a clear understanding of user and task requirements”. This advocates the importance of the close and frequent interaction in order to enhance the effectiveness of user involvement. HCD process is required exactly because of the facts that design principles and usability heuristics cannot be simply implemented and that especially for mobile “context (of use) is king” [80].
For any ICT-based systems, usability is essential to ensure good user experience. User
experience can be conceptualized as an overall impression of a product around use [57]. Thus, user experience goals could vary depending on the purpose of an ICT system. User experience is influenced by more factors than components of usability, although satisfaction is very much relevant. The most relevant user experience goal to this research is that a system feels
engaging to a user in a sense that it helps self-management of T2DM. As explained previously, self-management involves behavior change which is often times challenging to people with T2DM. In the next sub-section, I will describe a discipline that is specific to design of ICT systems for behavior change.
2.2.2 Persuasive technology
Persuasive technology is briefly explained as technology that is designed or used with “intent”
that a user would change his/her behaviors voluntarily by using the technology. This means that persuasive technology affects on a user with intention but does not affect by unintentional side-effect. Following to the definition, persuasion requires an “intentionality” to change both/
either attitudes and/or behaviors [81,82].
A number of frameworks10, models, strategies, principles, propositions for design and analysis of persuasive technology are proposed [81–90]. Although proposed frameworks use different terminologies, there are many commonalities among them. For example, Fogg’s
conceptualization of sources of intention [81]; endogenous, exogenous and autogenous, is used for the argument for clarification of persuader in the Persuasive System Design (PSD) model [86]. Three approaches to influencing behavior in Design with Intent [88] can be translated into motivation and ability in Fogg’s Behavior Model (FBM) [83], because
10 For convenience, I use the word “framework” as a generic name for frameworks, models, strategies, principles, and propositions in this sub-section.
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constraining behavior is reducing ability and motivation. Fogg’s Behavior Grid11 [85,91] and categorization used in Oinas-Kukkonen’s Behavior Change Support System are similar in terms of what type of behavior change is targeted. Especially the foci on relapse in behavior change are also common to propositions presented by Kraft et al. [89]. Twenty-eight design principles in the PSD model [86] include the seven strategies proposed by Fogg [82]. They have also commonalities with “Design Strategies for Lifestyle Behavior Change Technologies”
proposed by Consolvo et al. [90]. But the Design Strategies for Lifestyle Behavior Change Technologies provide more concrete arguments especially for design principle: “self-monitoring”, which needs to be “abstract and reflective”, “unobtrusive”, and “trending / historical”.
As persuasive technology should focus on users’ behavior change by interaction with it [82], various relevant psychological theories are incorporated in the proposed frameworks. For example, theories about rather intuitive judgments, such as “heuristics and biases” [92] or
“framing” [93] are explicitly used in Design with Intent methods [88]. Theories about longitudinal behavior change are also referred in several frameworks in common especially for lifestyle change to improve health condition [85,86,90]. Such theories include trans-theoretical model (TTM) [94] and goal-setting theory [95]. Theories from social psychology are also drawn and resulting in similar design strategies or principles in spite of different theories referred [86,90,96].
Ethics is an important perspective of persuasive technology from views of both persuasion and technology that raises ethical questions by nature in its use [81]. However, in a review of publications in a series of “Persuasive conferences”, Torning et al. [97] found that ethics was addressed at length as the topic in only three out of 51 reviewed papers. The authors criticize the current situation as “ethics being largely unaddressed might in itself be considered unethical” and advocate the importance of responsibility of designers and researchers on ethical aspects. To solve such situation, Karppinen and Oinas-Kukkonen [98] proposed a framework of ethical approaches in persuasive technology design, which provides pointers to ethical principles according to approaches categorized into; guideline, stakeholder analysis and user involvement. The third approach highlights the ethical issues more effectively and efficiently in designing and development process. By its nature that users who are direct stakeholders are participating as a member of design team, especially participatory design has a strong advantage in reducing potential ethical problems.
The frameworks described above can be applied to any domain as long as it concerns persuasive technology. There have been several review or viewpoint papers discussing the current situation and challenges of research on persuasive technology for health [99–101].
However, some of the review papers [97,102] pointed out that the methodologies taken are still described in vague manner in most of the reviewed studies and the authors advocate the needs for concrete design methods for successful development of persuasive technology.
Andrew et al. [103] pointed out that tactics to realize the strategies are missing. They found that the “suggestion” technologies had been relatively unexplored so far. They argue that suggestion technology would be important along the evolution of technology to provide suggestion with another important principle “kairos”. “Kairos” means to provide right information at right timing when it is most effective. They analyzed relevant literatures
11 Fogg’s Behavior Grid in [85] is a revised version of that proposed in [91] and the number of classified behaviors is reduced from 35 to 15.
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aiming to improve health behavior with various design strategies, and identified a list of dimensions that describe the design space of suggestion tactics in two categories:
technological dimensions and content dimensions. The proposed dimensions can be used for both designing and evaluating systems that employ the suggestion strategy as persuasive technology. Unfortunately, the process of identification of the dimensions is not described in the publication. However, the direction of their research suits the fifth and sixth steps of the Fogg’s eight design steps [84], which are “find relevant examples of persuasive technology”
and “imitate successful example”, respectively. This research by Andrew et al. is a good example of making a framework for identification of design requirements specification.