ABSTRACT
Usability
is the extent to which a product can be used by specific users to achieve
specified goals with effectiveness, efficiency, and satisfaction in a specified
context of use. The Nielsen’s usability model has been popularly used for
system usability evaluation. This thesis introduces a modification to Nielsen’s
usability evaluation model which was used to evaluate the usability status of
digital libraries in tertiary institutions in Lagos State. The digital
libraries used were that of University of Lagos, Lagos State Polytechnic and
Federal College of Education, Akoka. This modified model incorporates four
traditional attributes (Efficiency, Effectiveness, Satisfaction, Learnability)
and two additional attributes (Discoverability and Cognitive Load) introduced
by the researcher; these two attributes were introduced because they have been
proven to be user centered attributes which will help in getting the users’
personal experience while using the software (digital library) unlike the
existing usability evaluation models which were majorly system centered.
The
digital libraries will be assessed using modified heuristic think aloud method.
The study employed purposive sampling technique to select the three tertiary
institutions that was used for the evaluation while Yaro Yamani formula was
used to calculate the users’ population sample size of (40) for each of the
institution. Six task based questionnaires were used to carry out test in
collecting data for the study; they include: (i) Discoverability test, (ii)
Cognitive Load test (iii) Learnability test (iv) Effectiveness test (v)
Efficiency test and (vi) Satisfaction test. The mean of each of the usability
attributes were used to evaluate the usability status of the digital libraries
of the selected institutions. IBM SPSS statistics version 21 was used to
calculate the mean.
The
result of the usability test carried out established that the digital libraries
of the tertiary institutions in Lagos state were usable. It also indicated that
the users of the digital libraries were satisfied with the use of the digital
libraries in the investigated institutions. For the three institutions,
discoverability has a mean of 14.65, cognitive load has a mean of 14.81,
learnability has a mean of 16.21, effectiveness has a mean of 16.89, efficiency
has a mean of 16.56 and satisfaction has a mean of 16.27. Usability results of
the evaluated libraries showed that the digital libraries are: Effective,
Efficient, Satisfactory, helps users to learn and the discoverability and
cognitive load of the students are fast.
In conclusion, this study has successfully
modified the Nielsen’s usability evaluation model by adding Discoverability and
Cognitive Load to its constructs and this study has also contributed to
literature. The modified Nielsen usability evaluation model is recommended for
use to evaluate usability of other digital libraries in other tertiary
institutions in Nigeria and Abroad.
TABLE OF
CONTENTS
Title Page
Abstract
Chapter One: Introduction
1.1 Background
to the Study
1.2 Statement
of the Problem
1.3 Objective
of the Study
1.4 Research
Questions
1.5 Significance
of the Study
1.6 Scope
of the Study
1.7 Methodology
1.8 Operational
Definition of Terms
1.9 Organisation
of Subsequent Chapters
Chapter Two: Review of Literature
2.0 Introduction
2.1 Definition
of usability
2.1.1 Attributes of usability
2.1.2 Importance of usability
2.1.3 The role of usability in digital
libraries
2.2 Usability
Evaluation Models
2.2.1 Usability in ISO 9126
2.2.2 ISO/IEC 9126-1
2.2.3 Usability in ISO 9241
2.2.4 ISO 9241-11
2.2.5 Dix et al usability
evaluation model
2.2.6 Nielsen usability evaluation model
2.2.7 Eason usability evaluation model
2.2.8 Enhanced usability evaluation model
2.2.9 Normative usability evaluation model
2.2.10 Modified Nielsen’s usability
evaluation model
2.3 Usability
evaluation methods
2.3.1 Card Sorting
2.3.2 Open card sort
2.3.3 Closed card sort
2.3.4 Cognitive walkthrough
2.3.5 Focus group
2.3.6 Think aloud
2.3.7 Contextual Inquiry
2.3.8 Heuristic evaluation
2.3.9 Questionnaire
2.4 Digital
library
2.4.1 Role of digital library in Education
2.4.2 Sources of digital library
2.5 Review
of closely related work on usability evaluation
Chapter Three: Methodology
3.0 Introduction
3.1 Research
Design
3.2 Population
3.2.1 UNILAG digital library
3.2.2 FCE. (T) Akoka digital library
3.2.3 LASPOTECH digital library
3.3 Sample
size and sampling technique
3.4 Usability
model design/development
3.5 Method
of data collection
3.5.1 Think Aloud
3.5.2 Heuristic evaluation
3.5.3 Modified heuristic think aloud
method
3.5.4 Modified heuristic think aloud
evaluation
3.6 Evaluation
Tool
3.7 Tasks
in Usability Testing
Chapter Four: DATA ANALYSIS, Results and Discussion
of Findings
4.0 Introduction
4.1 Results
of Usability Tests
Research Question One
4.1.1 Discoverability Test
4.1.2 Cognitive Load Test
4.1.3 Learnability Test
4.1.4 Effectiveness Test
4.1.5 Efficiency Test
4.1.6 Satisfaction Test
Research
Question Two
Chapter Five: Summary, Conclusion and Recommendations
5.1 Summary
5.1.1 Summary of Findings
5.2 Conclusion
5.3 Recommendations
References
CHAPTER
ONE
INTRODUCTION
1.1 Background to the Study
The world has become a global
village where information technology is used in all spheres of human activity
to record, store, and disseminate information in the digital form. The new
generation whose demand for information is insatiable is always demanding that
traditional libraries be developed as a well-equipped and interconnected as
digital libraries. Information and Communication Technology has revolutionized
the concept of libraries such that libraries are gradually becoming digitized.
A digital library comprises digital collections, services and infrastructure to
support lifelong learning, research, scholarly communication as well as
preservation and conservation of our recorded knowledge. It is also a process
of democratization of information.
According to Arms (2012) a digital library is a managed collection of
information with associated services where the information is stored in digital
format and accessible over a network. A digital library is an organized
collection of digitized material or it’s holding in the digital form, which can
be accessible from digital devices on the network using Transmission Control
Protocol/Internet Protocol (TCP/IP) or other protocol. In digital library high
speed optical fiber are used for Local Area Network (LAN) and the access is
over Wide Area Network (WAN) and provide a wide range of Internet based
services including audio and video conferencing and others. Lynch (2013) opined
that digital libraries provide users with coherent access to a very large,
organized repository of information and knowledge.
According to the Berkeley Digital
Library Project, University of California (Wilensky, 2012), the digital library
will be a collection of distributed information sources. Some of the requirements
for digital libraries are: Audio visual (T.V, V.C.R, life theatre and D.V.D),
Computer, Network connectivity, Printer, Scanner, Storage devices, Software.
Digital libraries have features such as: Incorporating learning and access,
provides fast and efficient access to information, with multiple access modes,
collections which are large and persistent over time, well organized and
managed. The purpose of Digital Library
is to expedite the systematic development of procedures to collect,
store, and organize information in digital form, promote efficient delivery of
information economically to all users, encourage co-operative efforts in
research resource, computing, and communication networks, strengthen
communication and collaboration between and among educational institutions and
take leadership role in the generation and dissemination of knowledge. Digital
libraries are getting famous for flexibility of use and more users can be
facilitated at a time. As numbers of users increases, some issues relevant to
interaction also arise while using digital libraries interface and utilizing
its e-resources.
Usability is an important aspect of
evaluating applications. Usability standards should be followed by the websites
designer that supports user’s confidence level and interest when interacting
with the website. Interactivity is a basic principle underlying the
satisfactory behavior of the system by the user. System constraints are basic
conditions to operate functionalities that integrate different services and
sources in one interface that displays to develop interest of users. Searching
of information is an important perspective where usability is of high relevance
for user satisfaction. The interface is an important part in every system
because this is the part where the user directly interacts with the system and
utilizes services offered by the system. In every system, usability is a
reverse procedure which means it can be done at any phase of software
development life cycle. Specifically, students, teachers and researchers are
end users of the application and their interaction with the system shows the
satisfactory behavior. It helps developers or service providers to understand
how the application is used by the end users and if the system is fulfilling
user requirements or not. The best way to achieve this understanding is to
repeat a usability test after a period of time because it requires a lot of
changes to be made in the system, and for some users those are not satisfied
with the functionalities or interactivity with the system sources. Therefore,
usability testing is becoming an important ingredient in different types of
application.
The
International Standards Organization (ISO) (2014) defines usability 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"(p.10). Nielsen (2013) points out that usability has five
attributes: Learnability, efficiency, Memorability, low error rate or easy
error recovery, and satisfaction. Brinck, Gergle, and Wood (2012) share a
similar perspective that usability is functionally correct, efficient to use,
easy to learn and remember, error tolerant,
and subjectively pleasing. In addition, Booth (2013) outlines that
usability has four factors: usefulness, effectiveness (ease of use),
Learnability, and attitude (likeability). Hix and Hartson (2013) classify
usability into initial performance, long-term performance, Learnability,
retainability, advanced feature usage, first impression, and long-term user
satisfaction. The definitions given by ISO and Nielsen are most widely cited. Usability is about:
1.
Effectiveness
- can users complete tasks, achieve goals with the product, i.e. do what they
want to do?
2.
Efficiency
- how much effort do users require to do this? (Often measured in time)
3.
Satisfaction
– what do users think about the products ease of use?
The factors listed above is affected
by:
1.
The
users - who is using the product? e.g. are they highly trained and experienced
users, or novices?
2.
Their
goals - what are the users trying to do with the product - does it support what
they want to do with it?
3.
The
usage situation (or 'context of use') - where and how is the product being
used? (ISO
9241-11, 2012).
Usability is used to evaluate the digital
library. Usability is important because any product or system is finally
dependent on users who are to evaluate it. The digital library must pass the
usability test. The existing usability evaluation models have been used to
evaluate digital libraries abroad. It has been considered necessary to modify
model from the existing model that can meet the peculiar needs of digital
libraries in Nigeria.
1.2 Statement of the Problem
System
usability and system usefulness are interdependent properties of system
interaction while in combination, determines system satisfaction and usage.
Most usability evaluation models such as the Nielsen model, ISO model and Dix
model are majorly system centered, since digital libraries are to be used by
individuals there is a need for a model that is both system-centered and
user-centered. Many higher institutions in Nigeria provide academic digital
libraries and usability evaluation have been conducted in some of these digital
libraries; however, usability evaluation has not been conducted in UNILAG,
FCE(T) and LASPOTECH digital Libraries to gauge the performance of the system
in context of users’ perspectives i.e. how far the academic digital libraries
fulfill the users’ needs.
Also,
there is a need to know if the systems are useful to its users. Since digital
libraries are supposedly designed for people (as users) to use, evaluating the
performance of the system is of utmost importance. Therefore, this work
develops a modified evaluation model for evaluating digital libraries and will
be tested by end-users (students).
1.3 Objective of the Study
The
main objective of this study is to propose a modified usability evaluation
model and implement it using a digital library. The specific objectives are to:
1. modify Jacob Nielsen usability
evaluation model;
2. test the model developed in (i)
using three (3) digital libraries and
3. bench-mark the model against Nielsen
Usability evaluation model
1.4
Research Question
1. What is the usability status of a
given digital library using the modified model?
2. Using the modified model, how
acceptable is the model developed?
1.5
Significance of the Study
This research work is considered
significant as it would modify Nielsen’s usability evaluation model that would
be used for usability evaluation of digital libraries. Through this research
work, we would know how acceptable the model developed is and the factors that
contribute to the usability of digital libraries. These
factors would help us when laying down the prototype of the digital library. Information
provided would be credible, reliable and useful to enable the incorporation of
results obtained into decision making process of the professionals,
institutions and programmers in designing and improving their digital
libraries. We can also give suggestions to government,
education planners and school administrators on how to improve digital
libraries to meet up to standardized digital libraries. The result of this
research can help programmers, professionals and academic institutions in
building standard digital libraries for their respective institutions.
1.6
Scope of the Study
The scope of the project is to
modify Nielsen’s usability evaluation model that will be used to evaluate
usability status of digital library in any tertiary institution in Nigeria. The
research also uses the developed model to evaluate the usability status of a
digital library of a tertiary institution. The developed model would be tested
at the University of Lagos digital library, Federal College of Education
digital library and Lagos state polytechnic, Ikorodu digital library and the
following usability constructs (discoverability, cognitive load, efficiency,
effectiveness, learnability and satisfaction) would be used to evaluate the digital
library.
1.7
Methodology
We are modifying Nielsen’s usability
model and it would be used to test the usability of a digital library. To
achieve this, we will be using the modified Heuristic-Think aloud method.
1.8
Operational Definition of Terms
The
following terms are defined as used in this study.
Usability:
It 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 extent of use.
Digital library:
A digital library is a collection of information and digital contents that are
kept in digital formats and these are accessible to different users through
computers by having access to the internet.
Internet:
The internet is a global computer network that provides a variety of
information and communication facilities, consisting of interconnected network
using standardized communication protocols.
Modified
model: It
includes a combination of latent and observed variables. It allows you to
integrate all available knowledge into one approach will reducing effort and
maintaining accuracy.
1.9
Organization of subsequent Chapters
The
chapters are organized in the following order. Chapter One contains the discussion on the general area covered by
this research, the Chapter Two
provides specialized overview of the literature review, Chapter Three describes the methodology used for this research
work, Chapter Four contains the
result and discussion of findings and Chapter
Five contains summary of the work done, provides conclusions and
recommendations.
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