Firm foundation in the main hci principles, the book provides a working

8.3 Summary
We have looked at various methods for evaluating the interface at 
different stages in the development process. As already emphasized, 
even though all the required provisions and knowledge may have been 
put to use to create the initial versions of the UI, many compromises 
may be made during the actual implementation, resulting in a product 
somewhat different from what was originally intended at the design 
stage. It is also quite possible that during the course of the develop-
ment, the requirements simply change. This is why the explicit evalu-
ation step is a must and, in fact, the whole design-implement-evaluate 
Table 8.5 Summary of the Measurement Method
Evaluators/sample size
Potential or typical users/medium to large size (10 to 50 or more)
Type of evaluators
Balanced and homogeneous pool of subjects (users of the system—
gender, age, educational background, relevant skills, etc.)
Formality
Can be a formally controlled experiment or an informal assessment
Place
Laboratory or in situ field
Timing and objectives
STAGE
OBJECTIVE
ENACTMENT METHOD
Late/after
Interface design issues (look 
and feel, such as aesthetics, 
color, contrast, font size, 
icon location, labeling, 
layout, etc.)
Simulation
Actual system
Note: More reliable results, but generally time consuming to prepare and conduct the process.

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U S E R I N T E R FA C E E VA L U AT I O N
cycle must ideally be repeated at least a few times until a stable result 
is obtained.
References
1. Wikipedia. 2014. Usability. http://en.wikipedia.org/wiki/Usability.
2. Hart, Sandra G., Steve Land, and E. Lowell. 1988. Development of 
NASA-TLX (Task Load Index): Results of empirical and theoretical 
research. Human Mental Workload 1 (3): 139–83.
3. NASA. 2013. NASA Task Load Index. http://humansystems.arc.nasa.
gov/groups/tlx/downloads/TLXScale.pdf.
4. ISO. 2009. Ergonomics of human system interaction—Part 210: Human-
centred design for interactive systems. ISO DIS 9241-210:2010. Geneva, 
Switzerland: International Organization for Standardization.
5. Bevan, N. 2008. UX, Usability and ISO standards. Paper presented 
at Values, Value and Worth workshop, CHI 2008, Florence, Italy. 
http://www.cs.tut.fi/ihte/CHI08_workshop/papers/Bevan_UXEM_
CHI08_06April08.pdf.
6. Lewis, James R. 1995. IBM computer usability satisfaction question-
naires: Psychometric evaluation and instructions for use. International 
Journal of Human–Computer Interaction 7 (1): 57–78.
7. Wikipedia. 2013. Wizard of Oz experiment. http://en.wikipedia.org/
wiki/Wizard_of_Oz_experiment.
8. Nielsen, Jakob. 1994. Enhancing the explanatory power of usability heu-
ristics. In Proceedings of the SIGCHI conference on human factors in comput-
ing systems, 152–58. New York: ACM Press.
9. Likert, Rensis. 1932. A technique for the measurement of atti-
tudes. Archives of Psychology 22 (140): 1–55.
10. Rowley, D. E. 1994. Usability testing in the field: Bringing the laboratory 
to the user. In Proceedings of the SIGCHI conference on human factors in 
computing systems, 252–57. New York: ACM Press.
11. Kaikkonen, A., T. Kallio, A. Kekalainen, A. Kankainen, and M. Cankar. 
2005. Usability testing of mobile applications: A comparison between 
laboratory and field testing. Journal of Usability Studies 1 (1): 4–16.
12. Kjeldskov, J., M. B. Skov, B. S. Als, and R. T. Høegh. 2004. Is it worth 
the hassle? Exploring the added value of evaluating the usability of
context-aware mobile systems in the field. Lecture Notes in Computing 
Science 3160:61–73.

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13 7
9
F
U T U R E
O F
HCI
Human–computer interaction (HCI) has contributed much to the 
advancement of computing and its spread into our everyday living. The 
prevalent type of interface up to the late twentieth century was the 
so-called WIMP (windows, icon, mouse, pointer) and graphical user 
interface (GUI) for the stationary desktop computing environment. 
This was a huge improvement over its predecessor, the keyboard-input 
command-oriented interface. Much innovation has been made on the 
two-dimensional (2-D)-oriented desktop interface since it was first 
introduced in the early 1980s. These include ergonomic mouse and 
keyboard design, hypertext and web interface, user interface tool-
kits, extension of the Fitts’s law, interaction modeling, and evalua-
tion methodologies. If you look more closely, the innovation in HCI 
has always followed or been accompanied by an advancement of the 
hardware and software platforms. Even though the original concept 
of the mouse and graphical user interface was actually devised in the 
late 1960s by Doug Engelbart, it was not until the early 1980s that 
the hardware and software technology (not to mention the possibility 
of personal computing as hardware prices became much more afford-
able) was mature enough to accommodate the use of a mouse and the 
GUI (Figure 9.1).
This line of thought can give us a good glimpse into the future of 
HCI based on the fast-changing trends in computing platforms. Here 
are four major new computing platforms that have emerged in the 
past 10 years:
• Mobile and handheld platform: (exemplified by the smartphones) 
which we can carry around to compute and communicate
• Ubiquitous platform: in which everyday objects are embedded 
with interactive computing/networking devices and services
• Natural and immersive computing/sensing/display platform: that 
provides near-realistic services and experiences

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H U M A N – C O M P U T E R I N T E R A C T I O N 
• Cloud computing platform: that provides high-quality interac-
tive services (based on its heavy-duty ultraserver-level com-
puting power) with real-time response (based on the fast 
network service)
In the case of the cloud computing platform, the typical user will not 
interact directly with the system where the application resides (some-
where in the cloud), but through the client computer or device, such as 
the everyday desktop computers and mobile devices. Despite the tre-
mendous growth in the computing power of desktop and even mobile 
units, these stand-alone machines are not usually sufficient for such 
high-end interactive and intelligent services as image recognition, lan-
guage understanding, context-based reasoning, and agentlike behavior. 
Note that these so-called client devices (for the cloud) are becoming 
increasingly richer in their sensing, display, and network capabilities. 
In essence, the cloud is taking up the role of the Model and the cli-
ent View/Controller, where there can be many View/Controllers for 
different types of clients (e.g., desktops, pads, smartphones). This can 
be viewed as a way to improve the user experience (UX) by providing 
high-quality services in real time and having specialized interaction cli-
ents focused on usability that are easily deployed (due to their lightness 
and mobility). For such an envisioned future, it will be necessary to 
develop middleware solutions that will manage the seamless connection 
between the Model and one of many possible client View/Controllers.