<Previous Lesson

Human Computer Interaction

Next Lesson>



As the aim of this lecture is to introduce you the study of Human Computer
Interaction, so that after studying this you will be able to:

. Describe the relationship of Usability and quality

. Understand HCI Discipline
Human-computer Interaction is the kind of discipline, which is neither the study of
human, nor the study of technology, but rather the bridging between those two. So
you always have to have one eye open to the question: what can the technology do?
How can you build it? What are the possibilities? And one eye open to the question:
what are people doing and how would this fit in? What they would do with it? If you
lose sight of either of those, you fail to design well. And of course they require
different ways of thinking. So I think the challenge is to keep knowledge of both the
technology and the people playing off against each other in order to develop new
If you build something you need to consider not just ‘I’m building something because
I need to build it’, but ‘what effect is it going to have on the way people work and the
way people live?’

5.1 Quality

Let us firstly look at a general definition of quality.
According to the American Heritage Dictionary “characteristic or attribute of
something.” As an attribute of an item, quality refers to measurable characteristics---
things we are able to compare to know standards such as length, color, electrical
properties, malleability, and so on.
Now as we are concerned with software quality so let us look at some other
According to British Defense Industries Quality Assurance Panel “Quality is
conformance to specifications”. So, according to this definition quality is the measure
of degree to which the design specifications are followed during manufacturing. The
greater the degree of conformance, the higher the level of quality is.
Philip Crosby describes, “Quality is conformance to requirements.” Here software
requirements are the foundation from which quality is measured. Lack of
conformance to requirements is lack of quality.
Juran says, “Quality is fitness for purpose or use”
“Quality is a predictable degree of uniformity and dependability, at low cost and
suited to the market”, defined by Edward Deming.

By R J Mortiboys “Quality is synonymous with customer needs and expectations.”
“Quality is meeting the (stated) requirements of the customer- now and in the future.”
By Mike Robinson.
“Quality is the total composite product and service characteristics of marketing,
engineering, manufacturing and maintenance through which the product and service
in use will meet the expectations by the customer”
(Armand Feigenbaum)
“Totality of characteristics of an entity that bear on its ability to satisfy stated and
implied needs.”

ISO 8402 : 1994)

All above-mentioned definitions refer quality as a conformance to requirements or
conformance to specification or as a synonymous with customer needs and
expectations etc. In my point of view or with respect to HCI, quality is something
beyond meeting the specifications, requirements or customer expectations. For
example, consider a scenario, as you know, there is always a quality assurance
department in any software house which checks the final products with reference to
their specification or requirements. The products that do not fulfill their specifications
or requirements they are considered bugged. In my scenario, what will be the matter if
the specifications or requirements, which are being used to measure quality, are not
complete? That’s why, I think, quality is beyond the conformance to specifications or
requirements or even the customer expectations.
I think quality cannot be measured just by the requirements or specifications
described by the customer rather you should approach to that end user who will use
this product. The expectations or needs of the end user can be the measure of quality.
So, we can say, as much as the product will be useable for end user as much higher
will be its quality.
To understand the relationship of quality and usability in a software reference, look at
the definition of software quality. The extent to which a software product exhibits
these characteristics”







5.2 Interdisciplinary nature of HCI

The main factors that should be taken in account in HCI design are shown in above
figure. Primarily, these relate directly to users, such as comfort and health, or are
concerned with users’ work, the work environment or the technology being used.
What makes the analysis even more complex is that many factors inevitably interact
with each other. For example, if changes are made to improve productivity, this may
have undesirable effects on users’ motivations and levels of satisfaction because
issues relating to job design and work organization are ignored.

Case Study – Ticketing System

A small travel agency with a number of shops distributed throughout the country
decides that, in order to survive in the travel industry, it needs to install an efficient
ticketing system. Current practice involves sales staff in a lengthy procedure for
issuing tickets to customers. First they have to call an airline to check if there are any
vacant seats for the time when the customer wishes to fly. Then they have to check
with the customer which of the available seats is suitable before making a reservation
with the airline. The ticket is then written out by hand. In addition, the customer needs
a receipt and an itinerary, which are also written by hand. One of the biggest problems
with this practice is getting a telephone connection to the airline. This means that
customers often have to wait while a frustrated sales assistant keeps trying in vain. To
overcome this problem it is common practice to ask the customers to come back later
in the hope that the sales staff will manage to get through to the airline in the
meantime. Another time-consuming job is accounting for each ticket that has been
issued, and the sales staff has to do this by hand every two weeks.
Productivity Factors

Increase output, increase quality, decrease costs, decrease errors, decrease labour requirements, and decrease
production time, Increase creative and innovative ideas leading to new products

System Functionality

Hardware, software, application

Task Factors

Easy, complex, novel, Task allocation, repetitive, Monitoring, skills, multi-media

User Interface

Input devices, output displays, dialogue structures, User of colour, icons, commands, graphics, natural

Comfort Level

Seating Equipment layout
Cognitive processes and capabilities

The User

Motivation, Enjoyment, Satisfaction, Personality
Experience level

Health and Safety

Stress, headaches,

Environmental Factors

Noise, heating, ventilation,lighting Organizational Factors

Training, job design, politics, roles Work organization

Before deciding to get new system the branch manager does some background
research into how the agency really functions. She starts by visiting branches in a
sister company that is using a computerized ticketing system. After talking to the staff
for just a short time she discovers that there are problems. The sales staff complains
that the computer is always going wrong and that they don’t trust it. Furthermore, they
can’t understand some of the messages that it produces when they make errors. In
fact, they wish they could go back to the old un-computerized way of working. Sales
figures since the new system was installed are also disappointing and a large number
of staff have left the office. Not surprisingly, the manager is consultants examine the
users’ needs and how they currently go about their work in detail and also find out
exactly what the goals of the company are. They then recommend a system with the
following characteristics:

. Immediate ticket booking via a computer connection (alleviating the problem
of engaged phone line),

. Automatic print-out of tickets, itineraries and receipts (eliminating the need to
write these by hand and thereby reducing the possibility of errors and
illegibility while speeding up the process),

. Direct connection between the booking system and accounting (speeding up
the process of accounting),

. Elimination of booking forms (reducing overheads as less paper and time are
The consultants suggest making the interface to the system mimic the noncomputerized
task, so menus and forms are used, which means that the sales assistant
only has to select options and fill in the resulting forms by typing at a keyboard.
The consultants are optimistic that customer satisfaction will improve because
customer will get their tickets on the spot. They point out to the manager, however,
that in order to get the most out of the new system the layout of the agency needs to
be changed to make it comfortable for the sales staff to operate the compute, while
still providing scope for direct contact with customers. Staff will also need training,
and some careful changes to existing jobs are needed too—job design. In particular,
technology means that they will need support during the period of change. Staff will
also need to know how to cope when an airline’s computer malfunctions. Changes in
employment conditions must also be examined. For instance, if staff is expected to
carry out more transactions in less time, are they going to be rewarded for this extra
activity? Staff relations with other staff in the company who will not be using the
computerized system must also be taken into account. For example, problems
associated with technology power such as feelings f elitism among staff that know
how to use the new technology, will need to be resolved.
HCI understands the Complex Relationship between Human and Computers, which
are two distinct ‘Species’. Successful Integration is dependent upon a better
understanding of both Species. Hence HCI borrows and establishes its roots in
Disciplines concerned with both.


. Cognitive Psychology


. Social Organizational Psychology

. Ergonomics and Human Factors

. Linguistics

. Philosophy

. Sociology

. Anthropology


. Computer Science

. Artificial Intelligence


. Engineering

. Design

Cognitive Psychology

Psychology is concerned primarily with understanding human behavior and the
mental processes that underlie it. To account for human behavior, cognitive
psychology has adopted the notion of information processing. Everything we see, feel,
touch, taste, smell and do is couched in terms of information processing. The
objective cognitive psychology has been to characterize these processes in terms of
their capabilities and limitations. [2]

Social and Organizational psychology

Social psychology is concerned with studying the nature and causes of human
behavior in a social context. Vaske and Grantham identify the four core concerns of
social psychology as:

. The influence of one individual on another person’s attitudes and behavior

. The impact of a group on its members’ attitude and behavior

. The impact of a member on a group’s activities and structure

. The relationship between the structure and activities of different groups.
The role of social and organizational psychology is to inform designers about social
and organizational structures and about how the introduction of computers will
influence working practices. [2]

Ergonomics or human factor

Ergonomics, or human factor, developed from the interests of a number of different
disciplines primarily during World War II. Its purpose is to define and design tools
and various artifacts for different work, leisure and domestic environments to suit the
capabilities and capacities of users.
The role of ergonomist is to translate information from the above sciences into the
context of design, whether for a car seat or a computer system. The objective is to

maximize an operator’s safety, efficiency and reliability of performance, to make a
task easier, and to increase feelings of comfort and satisfaction. [2]


Linguistics is the scientific study of language (Lyons, 1970). From the point of view
of HCI there are several issues that may be better understood by applying knowledge
and theories from linguistics. For example, in the early days of command languages
there was some debate about whether or not the object to which a command applied
should come before or after the command itself. When deleting a file called ‘xyz’, for
example, should you type delete ‘xyz’ or ‘xyz’ delete. [2]

Philosophy, Sociology and Anthropology

A major concern of these disciplines until relatively recently has been to consider the
implication of the introduction of IT to society. More recently, attempts are being
made to apply methods developed in the social sciences to the design and evaluation
of systems. The reason for applying social science methods of analysis to HCI, it is
argued, are that a more accurate description of the interaction between users, their
work, the technology that they use and the environment in which they are situated can
be obtained. One application of social science methods has been to characterize
computer supported cooperative writing (CSCW), which is concerned with sharing
software and hardware among groups of people working together. The is to design
tools and ways of working which optimize the shared technology so that maximum
benefit can be obtained by all those who use or are affected by it. [2]

Artificial Intelligence

Artificial Intelligence (AI) is concerned with the design of intelligent computer
programs which simulate different aspects of intelligent human behavior. The
relationship of AI to HCI is mainly concerned with user’s needs when interacting with
an intelligent interface. These include, for example, the use of natural language and
speech as a way of communicating with a system and the need for system to explain
and justify its advice. [2]

Computer Science

One of the main contributions of computer science to HCI is to provide knowledge
about the capabilities of technology and ideas about how this potential can be
harnessed. In addition, computer scientists have been concerned about developing
various kinds of techniques to support software design, development and
maintenance. In particular, there has been a strong interest in automating design and
development when feasible. [2]

Engineering and design

Engineering is an applied science, which relies heavily on model building and
empirical testing. Design contributes creative skills and knowledge to this process. In
many respects the greatest influence of engineering on HCI and subsequently on
interface and system development is through software engineering.

Design too is a well-established discipline in its own right, which has potential
benefits when applied to HCI problems. An obvious example is graphic design.[2]


Human-Computer Interaction by Jenny Preece
Software Engineering A Practitioner’s Approach by Roger S. Pressman
Definitions of Quality - Sandeep's Quality Page.htm

<Previous Lesson

Human Computer Interaction

Next Lesson>


Lesson Plan


Go to Top

Next Lesson
Previous Lesson
Lesson Plan
Go to Top