QUALITY ATTRIBUTES OF CONSUMER-BASED

M-COMMERCE SYSTEMS

John Garofalakis

1,3

, Antonia Stefani

, Vasilios Stefanis

1,3

and Michalis Xenos

Research Academic Computer Technology Institute, 26500, Patras, Greece

School of Sciences & Technology, Software Quality Research Group, Hellenic Open University

23 Sachtouri Str, Patras, Greece

University of Patras, Computer Engineering & Informatics Department, 26500 Patras, Greece

Keywords: m-commerce Systems, ISO9126, Quality attributes.

Abstract: In m-commerce applications, the design process still lacks a systematic quality control procedure. These

systems are data-intensive, user-driven, and have increasing needs for accessibility, efficiency, adaptivity,

portability and competitiveness. In this paper we study the quality of the software on which retail shopping

through the mobile web is based, i.e. the software part of B2C (business-to-customer) m-Commerce system.

A consumer’s perception quality evaluation was conducted to reveal the quality attributes that offer insights

into m-commerce systems based on the external quality characteristics of ISO9126 quality standard.

1 INTRODUCTION

Mobile-commerce (m-commerce) systems have

been developed at a significant rate in recent years.

In particular, they offer functions and services in

order to fulfil the end-users requirements and to

provide services of high quality through a more

usable and user friendly environment.

M-commerce can be viewed as a subset of e-

commerce (Coursaris, 2002; Kwon, 2004) and refers

to transaction with monetary value that is conducted

via a mobile network (Clarke, 2001). When users

conduct e-commerce such as e-banking or purchase

products, they do not need to use a personal

computer system. Indeed, they can simply use some

mobile handheld devices such as Personal Digital

Assistants (PDA) and mobile phones. In the past,

these mobile devices or their enabling technologies

were regarded as a kind of luxury for individuals.

However, this situation has changed. The market for

mobile technologies has seen significant growth in

the past few years (Ngai, 2007). This is creating a

new opportunity for the growth of m-commerce.

Location-based services enable m-commerce to

be further leveraged so that the mobility aspect is

exploited of rather than repackaging old systems in a

new format. M-commerce systems have two major

characteristics: mobility and broad reach. Mobility

implies portability, e.g., users can conduct business

in real time via mobile devices. With m-commerce,

people can be reached at any time via a mobile

device. In this paper, m-commerce refers to

conducting commerce via wireless devices and

especially via mobile phones and examines end user

quality perspective.

The quality of m-commerce systems is an

extremely new and challenging task; especially the

quality of mobile commerce systems as it is

perceived by the end-user is an open research issue

for the software quality community. The end user

interacts with mobile system using software through

mobile devices and expects a well designed

environment where he/she can proceed a

commercial transaction.

It is with the above observation that this paper

examines the quality attributes of m-commerce

systems adopting the ISO9126 software quality

standard (ISO, 2001). Adopting and adapting ISO

9126 for specific domains is not new to the standard

itself (Losavio, 2004; Cote, 2005). The usual

approach is to enhance the hierarchical and (by

design) open scheme to include more attributes

suitable for the new domain. However, enhancing an

ISO standard is far from being an easy process.

130

Garofalakis J., Stefani A., Stefanis V. and Xenos M. (2007).

QUALITY ATTRIBUTES OF CONSUMER-BASED M-COMMERCE SYSTEMS.

In Proceedings of the Second International Conference on e-Business, pages 130-136

DOI: 10.5220/0002113101300136

 SciTePress

The quality of software concerns end-users and

developers as well. The main question posed is

“Which are the attributes that an m-commerce

system should have and how these attributes

formulate end user’s perspective about m-commerce

systems’ quality?” Another research question that

arises is that “An m-commerce system can be well

designed but it can also be characterized as a system

with high quality?” In this quality evaluation

approach the paper emphasizes at end-user

perceptive using the external quality characteristics

of ISO9126 namely Functionality, Usability,

Efficiency and Reliability.

The paper is structured as follows; in section 2

the theoretical foundations are presented, while in

section 3 m-commerce attributes are discussed. In

section 4 the evaluation process is presented, while

in section 5 the evaluation results and their quality

aspect are further discussed. Finally, in section 6

conclusions and future work are presented.

2 THEORETICAL

BACKGROUND

The method presented in this paper uses the external

quality characteristics of the ISO9126 quality

standard in order to model the quality attributes of

m-commerce systems. We strongly encourage

authors to use this document for the preparation of

the camera-ready. Please follow the instructions

closely in order to make the volume look as uniform

as possible. (Moore and Lopes, 1999).

2.1 The ISO9126 Quality Framework

ISO9126 is a quality standard for software product

evaluation and provides quality characteristics and

guidelines for their use (ISO, 2001). This standard,

composed of several parts, aims at defining a quality

model for software and a set of guidelines for

measuring the characteristics associated with it. This

work is based on the ISO9126 quality standard and

specifically it relies on the external quality

characteristics which are directly related to quality

as perceived by the end-users.

ISO9126 may be used as basis for m-commerce

quality evaluation but further analysis and mapping

of its characteristics is required. The main issue is

how m-commerce system’s quality can be analyzed

using this standard. In this work, we use the

following external quality characteristics of ISO

9126: Functionality, Usability, Efficiency and

Reliability. Each of the above mentioned

characteristics provide the quality framework

(actually the baseline) on which an m-commerce

system may be built, taking into account the

satisfaction of end-users requirements. The external

quality characteristics of ISO9126 are defined as

follows.

2.1.1 Functionality

Functionality refers to a set of functions and

specified properties that satisfy stated or implied

needs (ISO, 2001). The meaning of Functionality is

to provide integrative and interactive functions in

order to ensure end-user convenience. Especially for

m-commerce systems Functionality refers to the

existence of these functions and services that support

end user’s interaction via the mobile system.

2.1.2 Usability

Usability is defined as a set of attributes that bear on

the effort needed for the use of a product or service,

based on the individual assessment of such use by a

stated or implied set of users (ISO, 2001). Usability

is an important quality characteristic as all functions

of an m-commerce system are usually developed in

a way that seeks to facilitate the end-user by

simplifying end-user’s actions; this fact can however

affect negatively the system in certain cases.

2.1.3 Efficiency

Efficiency is a complex concept that entails both

conceptual challenges as well as implementation

difficulties. Efficiency is defined as the capability of

the system to provide appropriate performance,

relative to the amount of resources used, under

stated conditions (ISO, 2001). It refers to a state

where system functions are both usable and

successful, i.e. they achieve their aim, the reason for

their existence. One of the main criteria of efficiency

of an m-commerce system is the quality relating to

time and resource behaviour.

2.1.4 Reliability

Reliability is the quality characteristic that refers to a

set of attributes that bear on the capability of

software to maintain its performance level under

stated conditions for a stated period of time (ISO,

2001). Especially for m-commerce systems

reliability refers to systems tolerance on end users

actions.

QUALITY ATTRIBUTES OF CONSUMER-BASED M-COMMERCE SYSTEMS

131

3 M-COMMERCE SYSTEM

ATTRIBUTES

Currently, m-commerce is in its early stages of

development and little is known about the factors

that influence quality’s attitudes and their value from

the end-users’ perceptions. Mobile commerce

systems include mobile financial systems, mobile

advertising, mobile inventory management, product

locating and shopping, wireless reengineering,

mobile auction, and wireless data center (Malloy,

2002). These systems aim to provide the appropriate

attributes/functions for the end user in order to

complete a purchase or to get information using

his/her mobile device. The basic advantage of m-

commerce systems is that location and time do not

constrain people from completing their transactions.

In order to model the interactions among the end

user and the m-commerce system we consider three

different steps: Presentation, Navigation and

Purchasing. Presentation describes how a product or

service is presented to the end-user. Navigation

describes the various mechanisms provided to the

end user for accessing information and services of

the m-commerce system. Purchasing refers to the

facilities provided for the commercial transaction

per se. Applying the above steps to m-commerce

requires an adjustment to the attributes that the

system presents because of its wireless

communication character. In the following

paragraphs we present the attributes of mobile

systems that constitute the end-user purchasing

process. The definition of these attributes is

basically based on the literature for mobile web

practices and especially on Mobile Web Best

Practices 1.0, W3C Proposed Recommendation

(W3C, 2006), e-commerce and m-commerce

previous experience (Stefani, 2004; Stefani, 2005;

Blekas, 2006). In this work m-commerce attributes

are categorized in the above categories providing an

overview of m-commerce systems’ quality from end

users’ point of view.

The aim of this paper is not to describe all

existing m-commerce attributes or fully present their

use but rather to offer a quality evaluation of these

attributes and to present a quality framework for m-

commerce systems.

3.1 Presentation

Presentation is supported basically by text and

images because mobile devices have limitations

such as screen size and resolution, number of

supported colors, computation power, memory size,

rate of data transfer and energy required for proper

functionality. Color usage is also important. Using

colors obviously gives a pleasant and friendly

interface, but a too colored screen confuses. All the

pages of the m-commerce system must have the

same colors so the user can feel that he/she is

navigating in the same environment. By removing

background images, background colors and text

colors the readability of the content is increased. The

use of images in Internet applications is common.

Nevertheless, using images in mobile web

applications significantly increases download and

response time and thus, usage cost.

Presentation issues are also related to issues such

as thematic consistency and the default delivery

context which intends to provide an acceptable

mobile environment for any end user from different

mobile devices. The clarity of the text presented

with meaningful, short and simple words and the

presentation of the central meaning at the first page

of each mobile device contributes attributes that a

m-commerce system should provide to the end user

for an accessible mobile environment. Additionally,

providing a descriptive title for the page allows easy

identification of the content; by keeping the title

short reduces page weight.

3.2 Navigation

The navigability of an m-commerce system is a

critical factor for its success. Navigation is an

important design element, allowing users to acquire

the information they are seeking and making that

information easier to find.

Navigation issues support m-commerce systems

quality by taking into account the quality of

components such as indexes, navigation bars, site

maps and quick links. The availability of these

components facilitates access to information and

services and enables users to locate efficiently the

information they need, while avoiding usability

bottlenecks. Additionally, navigation concerns the

facilities for accessing information and the

connectivity of the above systems.

Navigation refers at attributes that support the

navigability of m-commerce systems. These refer to

navigation bars, which according to W3C Mobile

Web Best Practices 1.0, should be placed on the top

of the page. Any other secondary navigational

element may be placed at the bottom of the page if

really needed. It is important that users should be

able to see page content once the page has been

loaded with the minimum possible scrolling. M-

commerce systems, as e-commerce systems provide

ICE-B 2007 - International Conference on e-Business

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simple metaphors such as shopping cart where the

end-user may add the products that he/she intends to

buy. Mobile devices present limitations on text

inputting so an m-commerce system should be

enabled by attributes such as access keys (keyboard

short cuts), by providing defaults at any function that

the user should select an action and also by avoiding

free text with minimum text inputting. The

navigability of the mobile system is also supported

from search services which are related with device

capabilities and context presentation as well. Search

with simple text inputting in an AND/OR operator

format enables the user to find the information

needed without navigating to several mobile pages.

Search attributes can reduce the cost of mobile

browsing and prevent navigability difficulties.

Additionally, because of the limitations in

display and input mechanisms, the possible absence

of a pointing device and other constraints of mobile

devices, care should be exercised in defining the

structure and the navigation model of a Web site.

Especially the use of links should be limited aiming

at providing a balance between having a large

number of navigation links on a page and the need to

navigate multiple links to reach content.

3.3 Purchasing

Purchasing refers to all m-commerce systems

attributes that strongly support their commercial

character. In particular, it refers to attributes that

support the interaction with the m-commerce

system. These attributes are also related to the

navigability of the system but they are categorized

differently because of their significant contribution

to the purchasing process.

Localization services may enable the

presentation of the products and service because the

m-commerce system can recommend the best

selection based on end user’s positioning.

Authentication and personalization attributes support

an m-commerce system where the end user can

provide private information (ie. Credit Card

Number). Additionally notification services provide

a great advantage to m-commerce systems because

they can also be combined with localized

information. Alternative payment methods support

either a complete transaction via the m-commerce

system or otherwise combined with localized

information allow mobile users to conclude

transactions efficiently (e.g. receive a product at a

selling point closest to the user’s current location)

(Samaras, 2002).

Purchasing process success is also related to the

stability of the process via the m-commerce system

and issues like error tolerance and error recovery are

crucial.

4 QUALITY EVALUATION

METHOD

Quality evaluation of mobile applications, as long as

the end user’s requirements are concerned, gives

emphasis on the systems’ quality and especially on

ISO9126 external quality characteristics:

Functionality (F), Usability (U), Efficiency (E) and

Reliability (R). It is within this framework that the

end-users, who are also the customers of a mobile

network, will specify the relative significance for

each function that the mobile system provides to the

user.

End-user is the best judge (when properly

questioned) of the degree to which their needs are

satisfied, and thus of the quality of the system

viewed as a service. For the presented study, three

expert quality evaluators were selected in a heuristic

evaluation method (Nielsen, 1990). Heuristic

evaluation is performed by looking at an interface

and trying to come up with an opinion about what is

good and bad about the interface. Ideally people

would conduct such evaluations according to certain

rules, such as those listed in typical guidelines

documents. The evaluators for this method are IT

experts with experience in quality evaluation and

mobile systems as well. The nature of the presented

evaluation method demands the use of expert

evaluators because of its technical character.

Figure 1: Amazon's m-commerce system from Nokia N70.

Firstly, the evaluators were asked to a complete

purchase using a mobile phone and an emulator

from their PC. For the evaluation process we have

used the Nokia N 70 mobile phone. The N70 has a

screen with resolution 176 x 208 pixels and supports

QUALITY ATTRIBUTES OF CONSUMER-BASED M-COMMERCE SYSTEMS

133

262.144 colors. The phone can also connect to 3G

networks for high rate data transfers using the Opera

Mobile 8.51 browser. In order to avoid operability

issues for the Nokia N70, help about the

functionalities of the device was provided during the

evaluation process. Additionally the emulator that

has been used was the Openwave Simulator (version

7).

Figure 2: E-bay's m-commerce system from Nokia N70.

The three evaluators used three popular m-

commerce systems according to the Mobile Web

Google Search (www.google.com/xhtml) in order to

have the best m-commerce experience possible. The

m-commerce systems that have been selected were

Amazon.com, Ebay.com and Movietickets.com.

Each evaluator was asked to asses specific m-

commerce attributes and to evaluate each one by

assigning a value of relevance (rij). Relevance

defines the correlation among the m-commerce

systems attribute i (presented in table 1) and

software quality characteristic j ordered as they

presented in this work (i.e. j=1 for Functionality, j=2

for Usability, j=3 for Efficiency and j=4 for

Reliability) using a five-grade Liker-type scale (1).

Each evaluator selected a different value for each

quality characteristic from the Liker-type scale

assigning scale.

⎪

⎩

⎪

⎨

⎧

ncorrelatiocritical

ncorrelatiostrongvery

ncorrelatiostrong

ncorrelatioweak

ncorrelationo

(1)

This provides a qualitative representation of m-

commerce systems quality and especially gives

emphasis on external quality characteristics.

Figure 3: Movietickets’ m-commerce system from Nokia

N70.

Figure 4: Payment method at movietichets.

5 EVALUATION RESULTS

Quality evaluation of m-commerce systems

attributes provides a quantitative representation of e-

commerce systems’ quality. Table 1 provides the

evaluation results for the m-commerce attributes

presented in section 2. It presents the values of

function relevance (r) for each attribute. These

values are the average values of all evaluators

approximated in monad.

Based on the evaluation results, the quality of m-

commerce systems can be modelled in external

quality characteristics and attributes. Providing a

value for each attribute, an ordered list for each

external quality characteristic is provided.

These values provide a first impression of end

users preferences and perquisites about m-commerce

systems’ attributes.

ICE-B 2007 - International Conference on e-Business

134

Table 1: Evaluation results for m-commerce attributes.

M-commerce attributes

Quality

characteristics

F U E R

Presentation

Product’s description

3 5 3 3

Still images

3 5 3 1

Text

4 5 3 2

Colors

3 5 4 2

Graphics

4 5 3 2

Clarity

3 5 4 2

Central meaning of

content

3 5 4 1

Text inputting

4 5 4 1

Thematic consistency

2 5 4 2

Provide defaults

3 5 4 2

Navigation

Navigation mechanism 4 4 4 3

Uploading Time 3 3 5 4

Access keys 4 5 4 2

Use of Links 4 4 3 3

Help 5 5 3 3

Feedback 3 5 4 3

Undo functions 5 3 3 5

User oriented hierarchy 2 5 4 3

Redirection 5 3 4 3

navigation bar (minimum) 5 5 3 1

Scrolling 3 5 4 2

Search response time 2 4 5 4

Search results processing 3 4 5 3

Purchasing

Shopping cart –Metaphor 4 5 4 2

Security mechanism 3 2 4 5

Pricing Mechanism 3 4 3 3

Alternative payment

methods

4 4 3 4

Authentication 5 2 3 5

Personalization 4 5 4 2

Localization 4 5 3 1

Transaction recourses

behavior 3 3 5 4

Notification services 3 5 3 4

Error recovery 3 3 3 5

Errors tolerance 4 3 4 4

Stability 4 3 3 5

The categorization of these attributes provides

important feedback for m-commerce systems’

assessment which is in an initial stage. By evaluating

the attributes that an m-commerce system provides

to the end user we also offer an end user perception

of quality. End user’s experience is a critical

determinate of success in mobile web applications.

If end users, who are also the customers, cannot find

what they are searching for, they will not buy it; a

site that buries key information impairs business

decision making. Poorly designed interfaces increase

user errors, which can be costly. A user-centered

evaluation approach supports all the tasks users need

to accomplish using different m-commerce systems’

attributes. The above evaluation process provides

measurement results which can be also be defined as

metrics for a quantitative representation of m-

commerce systems’ quality.

In order to evaluate m-commerce systems

features a new metric that summarizes the relevance

of each attribute is introduced. The metric Mobile

Attributes Weight (MAW) provides an evaluation

weight with respect to the four quality characteristics

and is calculated by formula 2,

]1,0[

∈=

∑

rnormalizedMAW

(2)

where r

is the relevance for every listed m-

commerce system attribute. The value for MAW

provides a numerical value for every m-commerce

system attribute and an ordered list about end user

preference based on external quality characteristics.

The values for MAW need to be further specified,

probably with experience testing in future work and

the use of different end users’ groups.

The metric MAW actually represents attributes

importance for the end-user and as such it can be

used at the development phase in order to define end

user preferences.

The evaluation process also provided interesting

results about the quality characteristics. In an up and

down processing of the values for rij, the WF=0,24,

WU=0,30, WE=0,26, WR=0,20 values have been

defined as the normalized average values for each

quality characteristic. From these values we

conclude that m-commerce end users give great

emphasis to Usability and Efficiency issues and

somewhat lesser on Functionality and Reliability.

These values differ from e-commerce systems where

Usability and Functionality have equally great

importance (Stefani, 2004). In e-commerce systems

the end users expects different and usable

functions/services, but in m-commerce systems the

end user desires the basic functions with great

efficiency when it comes to time and resource

behaviour.

QUALITY ATTRIBUTES OF CONSUMER-BASED M-COMMERCE SYSTEMS

135

6 CONCLUSION AND FUTURE

WORK

In this paper, we presented a quality evaluation for

selected attributes of m-commerce systems and

particularly B2C m-commerce systems. This

evaluation provides an extendable framework useful

for mobile system developers. We believe that this is

a step towards more effective measurement of m-

commerce systems’ quality. We acknowledge that

our attributes do not constitute a complete set and

may not cover every aspect of m-commerce systems.

The above evaluation results provide an initial

research for m-commerce systems’ quality.

A metric MAW has also been introduced which

measures the value of relevance for each m-

commerce system attribute. The theoretical

framework for this metric is also presented. The

validity of the presented measures should further

examine with different user groups in alternative

evaluation cases and it is included in future work. It

should be mentioned that the values presented

are not strictly defined as numerical results but

present the correlation among m-commerce systems

attributes and external quality characteristics.

Future work includes the development of

methods enabling the selection of the most

appropriate set of metrics for each evaluation

process. We also suggest the creation of an open

knowledge base of web-based m-commerce

systems’ quality factors, criteria, and metrics

according to end users’ needs.

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