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ABSTRACT
Online group-buying has emerged as a new e-commerce model and received
attention in both academics and practice. Prior researches focused on investigating
online group-buying mainly from the marketing perspective, such as the transaction
process, price mechanism, and benefits (Li & Liu, 2012). Few of studies have
investigated the relation between consumer’s acceptance and their purchasing
behavior. Hence, this study focuses in measuring relationship between cognitive
factors – trust, satisfaction and perceived usefulness – and online group-buying
repurchase intention. Simultaneous, this study also integrates website quality - a direct
and indirect variable – to measure its impact on customer repurchase behavior.
To examine research model, information and data is accessed by using
questionnaire for respondents more than 18 years old and have ever purchased on
online group-buying websites. Sample size of this quantitative research is 365
respondents. Confirmatory factor analysis (CFA) is used to test measurement scale
and the structural equation modeling (SEM) is used as the main method for analyzing
research model and hypotheses.
Results in this study show that individual user’ intention to repurchase in online
group-buying websites is motivated by trust, satisfaction and website quality. Among
three impact factors, website quality has the strongest direct influence, followed by
trust and satisfaction. Besides direct influence, website quality also has indirect
impact on customer repurchase intention through both of trust and satisfaction. Trust
also has strong impact on customer satisfaction, thus, affect indirectly to customer
retention.
With these results, research framework can be seen fitted with data market. Study
results also suggest that in order to increase customer retention should not only
consider about their strategies of increasing trust and satisfaction, they should also

reviews. To nowadays, online shopping continues their rapid spread and gains many
increasing importance in the lives of a wider range of the population.
Group-buying is seen as an effective form of online shopping and a promising field
for applying agent technologies. Group-buying is a model in which multiple buyers
cooperate and buy goods at a discount price (Matsuo, 2009). Innovative group-buying
sites offer bargains on everything from meals to travel packages. Customers can make
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comparison of product/service prices and choose the supplier with the lowest price
(Gounaris et al., as cited in Li & Liu, 2012) when using this new model.
With the tremendous growth, online group-buying attracted more and more
attention of practitioners as well as researchers. However, most previous online group-
buying studies focus mainly on the pricing mechanisms, coalition formation, benefits
of bidder cooperation, uncertain demand, incentive mechanisms and consumer
adoption (Fan et al., 2010). There are not many studies investigated the relationship
between customers’ acceptance of online group-buying and their purchasing behavior.
In recent years, this topic begins become a hot issue, especially, continuance behavior
receives more attention because this issue at an individual level has been regarded as
crucial for sustainable web-based services (Premkumar & Bhattacherjee, 2008).
Besides that, many online group-buying websites as well as others online websites
are facing strong competition due to the evolution and proliferation of web-based
services. Moreover, web-based services have low entry barriers by its nature, if one
service is created, then a number of comparable alternative web-based services
follow, resulting in a high switching rate between those services by users
(Vatanasombut et al., as cited in Lee & Kwon, 2011). Thus, many online group-
buying providers are struggling to find strategies to exist in this difficult period.
Retaining their existing customers becomes a strategic way to ensure the company's

have become popular among Vietnamese students and white-collar workers due to
attractive discounts and a wide range of services and products
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.
To the end of 2011, there are almost 100 group-on sites in Vietnam with more
than 6700 deals and 4.2 millions sold out vouchers
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. Four leading group-buying
websites include: Nhommua, Hotdeal, Cungmua and Muachung. Ho Chi Minh City is
the strongest competition market with about 74% transaction deals and many
followers
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. Other markets such as Da Nang, Binh Duong, Can Tho… begin introduce
this new model, however, amount of transaction is still limited.
Along with development of group-buying market, perceived risk and competition
between rivals also increase very strongly. The biggest challenge for group-buying

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sites is method of payment and privacy. In Vietnam, many people are still not familiar
with online transaction. With weak privacy security system, customer beliefs have
trend of reducing when purchasing vouchers by money transfer or cash on delivery
method. Besides, there are many partners who do not follow the contract, provide bad

1.3 Research objectives:
As discussion in section 1.1, information system (IS) retention has been one of the
most recently explored topics in the IS research field. Many theoretical perspectives,
to nowadays, have been advanced in order to understand what motivates individuals
to repurchase in online group-buying websites. Thus, based on literature covering the
concept of IS continuance model and circumstance of online group-buying market in
Vietnam, this paper aims:
 To propose a model predicting customers’ repurchase intention in online
group-buying context in Vietnam.
 To investigate impact of website quality on customers’ repurchase intention
in online group-buying context.
 To examine impact of cognitive factors (trust, satisfaction and perceived
usefulness) on online group-buying repurchase intention.
This study is necessary for development of group-buying market in Vietnam. It
also demonstrates that website quality is a noteworthy factor affect repurchase
intention of customers in using online group-buying.
1.4 Methodology and scope of research:
Collecting data process of this study is designed into two stages. First is a pilot
test, second is main survey to collect data for examining research model. Pilot test is
quantitative research with sample 57 respondents to examine reliability and validity
of observed variables. Main study is also quantitative research with sample size 365
respondents.
Author accesses information and collect data by using questionnaire. Respondents
are more than 18 years old and have ever purchased on online group-buying websites.
Sample is selected by using non-probability sampling method – convenience sample.
Research is studied from September 2012 to December 2012.
Purpose of this research is to confirm and examine conceptual model. The
measurement scales are estimated using confirmatory factor analysis (CFA) to test
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2.2 Theoretical background:
2.2.1 Online group-buying model:
Group-buying, also known as collective buying, introduced in 1999 by a few of
companies. After introducing time, this model have been facilitated by the internet and
the easy, fast group coalition process brought by social networks (Xiong & Hu, as
cited in Erdogmus & Cicek, 2011). It is seen as a part of an innovative wave of online
market-based pricing mechanisms, includes traditional auctions, non-traditional
auctions, price-reduction models and group-buying models.
There are mainly two different types of online group-buying systems (Fei et al., as
cited in Erdogmus & Cicek, 2011). First type of this system is structured based on a
dynamic pricing mechanism. In this first type, masses of consumers are aggregated,
and perform collective buying to enjoy price discounts online. In the second type of
the online group-buying, the group-buying company offers a certain product or
service at a static large discount price. This price required the total number of the
buyers must be greater than the predetermined limit of the minimum required number
of buyers.
Today, many online websites are using group-buying models and have got great
success. These websites usually offers a large of products and services at significantly
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reduced prices. These websites claim they can negotiate low prices with manufacturers
and suppliers, and then pass these savings on to their customers (Kauffman & Wang,
2001).
However, group-buying websites, like other online shopping websites, are facing the
problem of obtaining market attention. With group-buying models, online group-buying
websites need not only a critical mass of consumer patronage and interest, but also a
significant amount of transaction volume so as to be able to profitably deliver on

“online repurchase intention”, “continue to shop online”, “customer intention to
return”, “web site stickiness”, and “continued information systems/IT intention”
(Wen et al., 2011).
2.2.2.1 Online customer retention:
Online customer retention in recent years, become a hot issue in both the IT and
marketing areas. Studies of this topic have been mainly divided into two streams
consisted of studies based on static-type models and process-type models (Lin & Ong,
2010).
(1) Static-type researches are derivation from concepts such as theory of planned
behavior (TPB), Fishbein and Ajzen's theory of reasoned action (TRA) or
technology acceptance model (TAM). The theory of Reasoned Action assumes
that if people view a behavior as positive (attitude), and if they believe that
others would prefer them to perform the behavior (subjective norm), there will
be a greater intention (motivation) to behave in that manner and they are thus
more likely to do so (Udo et al., 2010). TPB adds one major predictor –
perceived behavioral control – “to account for times when people have
intention of carrying out a behavior, but the actual behavior is thwarted because
they lack confident or control over behavior” (Miller, as cited in Udo et al.,
2010). Along with these theories, TAM has been confirmed as the most popular
parsimonious framework used to explain customers’ behavioral intention. TAM
is model that explains user intention and behavior based on forward-looking or
prospective expectations about IT usage. This model found perceived
usefulness and perceived ease of use as salient beliefs influencing IS
acceptance behaviors across a broad range of end-user computing technologies
and user populations (Davis et al.; Mathieson; Taylor and Todd, as cited in
Bhattacherjee, 2001). However, many empirical studies also comparing the
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consumer satisfaction, post-purchase behavior and service marketing in general
Perceived
Usefulness
Satisfaction
Confirmation
IS continuance
Intention
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(Anderson and Sullivan; Dabholkar et al.; Oliver; Patterson et al.; Tse and
Wilton, as cited in Bhattacherjee, 2001). Many researches try to add new
construct, and integrate studies that combine these models and another theory or
model.
In addition to the mainstream researches, there is a recent focus on affective
factors. According to Lee & Kwon (2011), the factors suggested classified into two
categories: cognitive and affective. Cognitive factors are those related to the mental
process of knowing, including aspects such as perception, reasoning and judgment.
Representative cognitive factors are: perceived usefulness, satisfaction, trust,
perceived ease of use, security, confirmation and disconfirmation, perceived risk,
perceived switching cost… In contrast, affective factors are related to specific
emotions or states of feeling. Some affective factors are studied in recent years such
as perceived playfulness (enjoyment), pleasure, arousal, familiarity and intimacy. Lee
& Kwon (2011) also suggested that customer retention research has shifted its focus
from cognition-oriented factors to affective factors to explore more factors
influencing on customer behavior.
Table 2.1: Some integrated models of customer retention
Study Characteristics of the research model Research domain


Roca et al.(2006) An integrated study
that combines EDT model and TAM
model, adds perceived quality and perceived usability as
new factor
E- learning
Liao et al. (2007)

An integrated study that combines EDT model and the
theory of Planning Behavior, adds subjective norm as a
new factor
E
-
serv
ice

Chiu and Wang (2008)

An integrated study that combines United theory of
Acceptance and Use of Technology, adds subjective
task
value as a new factor
Web–
based learning
Source: Lee & Kwon (2011)
13 satisfaction. This study show that service quality has strong effect on customer
satisfaction, thus, indirectly influence to customer loyalty.
In summary, very little studies in online group-buying context focus on customer
buying behavior, especially, customer retention. While the online market is growing
and profitable, the competition for market share is also increasing. To remain
competitive, it is imperative for online providers to invest time and money to find out
strategy to keep existed customers. Studies of customer retention are really necessary
for development of online group-buying model in the future.
2.2.3 Website quality:
Quality is not a new concept in information systems management and research.
Information systems practitioners have always been aware of the need to improve the
information systems function so it can react to external and internal pressures
and face the critical challenges to its growth and survivability (Aladwani & Palvia,
2002). However, to nowadays, both the conceptualization and the measurement of
website quality have been two debated topics.
In study of Éthier et al. (2006), research on the concept of website quality can be
classified broadly into four complementary research categories. (1) The first focuses
on functionalities and/or content of website. The dimensions identified have generally
been: functional issues, navigation, content, technical issues and contact information
(2) The second category includes researches affected by technology acceptance model
TAM, relationship between perceived ease of use and perceived usefulness can be
seen as a relation of quality. Information quality, system quality and service quality of
websites are the essential components of website quality. (3) The third category
includes studies that highlight service quality as a fundamental aspect of the overall
quality of a website. E-service quality and website quality sometimes are use
exchangeable. Many researchers try to make conceptualization of service quality of
website, for instance, Zeithaml (as cited in Li, 2010) defines e-service quality as the

website quality, many studies show more different dimensions in website quality, for
examples: Madu &Madu (2002, as cited in Li & Suomi, 2009) develop a 15
dimensions scale of website quality, which is built on better understanding of
customers and providing services to meet the needs and expectations of customer;
Field et al. (2004, as cited in Li & Suomi, 2009) develop process model for assessing
and improving website quality by identifying e-service system entities and
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transactions between those entities and mapping key quality dimensions onto them.
Most recently years, Sohn & Tadisina (as cited in Li, 2010) proposed six dimensions
to measure website quality, include: trust, speed of delivery, reliability, ease of use,
customized communication, website content and functionality.
Among studies of website quality instruments, most researchers develop adapted
website quality scales based on the modification of the SERVQUAL instrument.
SERVQUAL scale is measurement scale had been used widely to measure service
quality with five dimensions: tangibles, reliability, responsiveness, assurance, and
empathy (Iwaarden, Wiele, as cited in Li, 2010). When adapting to e-commerce
context, Zeithaml (2000, as cited in Li & Suomi, 2009) proposed a 7-dimension
website quality scale. Later, Panasuraman et al. (2005, as cited in Liu & Wu, 2012)
developed it into seven constructs divided into two groups, includes: core e-SQ:
efficiency, fulfillment, availability, privacy; recovery e-SQ: responsiveness,
compensation and contact. To nowadays, these instruments is used popular in many
studies because it offers the surface dimensions of e-service quality based on
customers’ experience and evaluation perspective, which are viewed also as the
antecedents to the adoption of e-service (Rowley, as cited in Li & Suomi, 2009).
In general, website quality concept remains underdeveloped and is a vastly
undefined concept. This is a complex concept which has multiple dimensions.

customers’ IS use and purchasing behavior needed to investigate. “Online group-
buying repurchase intention” construct was acceptable with this study.
Secondly, two cognitive factors in expectation-confirmation model (ECM) –
satisfaction and perceived usefulness - were chosen for this study because they
commanded a majority of factors found to affect customer retention in prior studies.
Simultaneously, it ensures that the nomological structure of the research model is
consistent with the traditional belief-attitude-intention linkages in IS literature (Davis,
Bagozzi & Warshaw; Venkatesh et al., Ajzen, as cited in Li, 2010). In these linkages,
satisfaction is typically viewed as user attitude towards IS, which is primarily
measured by various beliefs about IS and posited to have strong saliency in predicting
continuance intention. Perceived usefulness in this study represents as IS user beliefs
and is a salient determinant of behavioral intention regarding IS use in TAM.
Thirdly, trust was added to the model due its role in influencing both satisfaction
and online repurchases intention. Trust in sellers is a vital key to maintaining
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continuity in the buyer relationship. An individual level of trust may increase
gradually based on positive outcomes from repeated behavior, although its important
in determining repeat purchase intention may decrease over time (Chiu et al., 2012).
Especially, in Viet Nam market, when some online group-buying websites faced
many problems make customer trust decrease, studies of the impact of this factor on
customer behavior become necessary for practitioners in improving and developing
their business.
Finally, website quality in this proposed model was also incorporated as a factor
leading and influencing to customer behavior through three constructs: perceived
usefulness, customer satisfaction and customer trust.
A review of the literature evaluation reflected that there were many instruments to

Figure 2.2: Research model
2.3.1 Perceived usefulness:
Drawing from TAM, post-consumption expectation is represented as ex-post
perceived usefulness in the proposed IS continuance model (Bhattacherjee, 2001).
Davis (1989) defines perceived usefulness as “the degree to which a person believes
that using a particular system would enhance his or her job performance. According
to Burk (as cited in Al-maghrabi et al., 2010) perceived usefulness is the primary
prerequisite for mass market technology acceptance, which depend on consumers’
expectations about how technology can improve and simplify their lives (Peterson et
al., as cited in Al-maghrabi et al., 2010). Numerous empirical investigations have
established strong empirical support for direct impact of perceived usefulness on
intention. So, in this study, perceived usefulness is proposed factor captures the
instrumentality of IS use, and influences subsequent continuance decisions.
Hypothesis 1a: Customer perceived usefulness is positively associated with online
group-buying repurchase intention.
Besides an important predictor of initial intention to use information system (Davis;
Davis et al., cited in Liao et al., 2006) and of intentions for continued use
(Bhattacherjee, 2001), perceived usefulness also influences indirectly to customer

from the appraisal of one’s job.” This definition is extended by Oliver (as cited in
Bhattacherjee, 2001) to the consumption context as “the summary psychological state
resulting when the emotion surrounding disconfirmed expectations is coupled with
the consumer’s prior feelings about the consumption experience.” In many
researches, customer satisfaction has usually been applied to measure e-commerce
success or consumer repurchase behavior. Oliver (as cited in Fan et al., 2010) shows
that satisfaction has both direct and indirect connections with future intention through
its impact on attitude. Hence, proposed hypothesis of this study is:
Hypothesis 2: Customer satisfaction is positively associated with online group-
buying repurchase intention.
2.3.3 Customer trust:
In general, trust is viewed as a set of specific beliefs dealing primarily with the
benevolence, competency, and integrity of another party (Doney and Cannon, as cited
in Chiu et al., 2012). According to TRA, trust can be viewed as a behavioral belief
that creates a positive attitude toward the transaction behavior, which is turn leads to
transaction intentions (Pavlou and Gefen, as cited in Wen et al., 2011). The role of
trust is more important compared to traditional business as increasing uncertainties
will be cause by the distance and other impersonal factors. Many previous researchers
show that the violation of trust in e-commerce will lead to negative repurchase
intention and negative word of mouth communication. Lack of trust prevents buyers
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from engaging in online shopping because they are unlikely to carry out transactions
with sellers who fail to convey a sense of their trustworthiness, mainly because of
fears of sellers’ opportunism (Hoffman et al., as cited in Wen et al., 2011). So, trust
plays an important role on driving repeat purchase intention. Following hypothesis is
proposed:

consumer’s specific service encounter (Li, 2010). Numerous studies have been
conducted to clearly demonstrate the relationship between service quality and
satisfaction. Fornell (as cited in Tien et al., 2012) proposed that website quality
positively affect overall customer satisfaction. Hence, this study proposed:
Hypothesis 4b: Website quality is positively associated with customer satisfaction
In study of Mcknight et al. (as cited in Liao et al., 2006), authors showed that if
consumers perceive that website quality is of high quality, they are likely to have high
trusting beliefs about the web retailer’s competence, integrity, and benevolence; and
will develop a willingness to depend on the web retailer. Zhou et al. (as cited in Li,
2010) also found that service quality had a stronger impact on consumer trust and
satisfaction. So, it is suggested that:
Hypothesis 4c: Website quality is positively associated with customer trust
Service quality usually was demonstrated to be an antecedent to satisfaction and
asserts a direct influence on consumer satisfaction (Anderson & Fornell; Sweeney &
Soutar, as cited in Li, 2010). However, some prior marketing literature also had
evidence showing that service quality affects the purchasing intention. Study of Liang
&Lai (as cited in Liao et al., 2006) showed that a high quality website not only affects
the customer’s purchase decision, but also is one of the main reasons for consumers to
determine whether they will purchase online or not (Gehrke & Turban, as cited in Liao
et al., 2006). Poor quality can result many loss in completion such as loss of
customers, reduction in profits, increasing costs… Therefore, website quality turn
leads to behavioral intention to use and reuse of customer. So, hypothesis is proposed
that:
Hypothesis 4d: Website quality is positively associated with online-group-buying
repurchase intention
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was full-time and part-time students who were studying at University of Economics
Ho Chi Minh City. They also were individuals who had experience in group-buying
and still had repurchase intention.
The pilot test of this study was conducted to assess the validity and reliability of
the instrument before the questionnaire was distributed. The initial data was collected
from a sample 70 randomly; however, only 57 questionnaires were collected. The
pilot study helped ensure that the final questions would be well understood and
attempted to predict an appropriate sample size and improve upon the study design
prior to performance of a full-scale research project. Simultaneously, cronbach alpha
and exploratory factor analysis (EFA) was used to test measurement scales.
Main survey was also quantitative research to collect data for examining research
model. The sample for this survey was also individuals who had experience in group-
buying but with a large amount. Based on rule of five observations per parameter
estimated, the minimum sample size needed for testing overall model was 205 (there
were 41 free parameters), hence, for the survey, 600 questionnaires were distributed
directly and email to respondents. After the data collection, total 550 responses were
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collected, 185 responses were eliminated because respondents indicated that they had
never use online group-buying before or they had no intention to repurchase. Finally,
365 responses were used as a valid data for this research. In this main study,
exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were used
to assess measurement scales. The structural equation model (SEM) had been used as
the main method for analyzing the research model by testing the assumed causation
among a set of dependent and independent variables. Bootstrapping with N = 1000 re-
samples was also used to assess the path significance.


Composite reliability and Average
variance extracted
(Examine reliability validity)

CFA - Confirmatory factor analysis
(Examine discriminant and convergent
validity)

SEM – Structural Equation Model
(Examine research model)
Draft Scale

Final Scale

Main survey -
Quantitative
research
(n=365)