FOREIGN TRADE UNIVERSITY
HO CHI MINH CITY CAMPUS
--------***--------
REPORT
RESEARCH METHODS FOR ECONOMICS AND BUSINESS
INFLUENCE OF REFERENCE GROUPS ON
ONLINE IMPULSE BUYING BEHAVIOR:
A STIMULUS ORGANISM RESPONSE FRAMEWORK
Class: K61CLC4
Student Name
Student ID
Trần Thị Kim Ánh
2212155038
Nguyễn Lê An
2212155027
Grade (in number)
Grade (in words)
Examiner 1’s signature
Examiner 2’s signature
Supervisor: PhD. Lê Hằng Mỹ Hạnh
Ho Chi Minh City, 16th February 2023
Table of Contents
Abstract .................................................................................................................................................. 4
1. Introduction...................................................................................................................................... 4
2. Literature Review ............................................................................................................................ 6
2.1 Impulse Buying ........................................................................................................................................6
2.1.1 Definition of Impulsive Buying ...................................................................................................................................... 6
2.1.2 Online impulse buying ....................................................................................................................................................... 6
2.1.3 Factors influencing impulse buying ............................................................................................................................. 6
2.2 Reference group .......................................................................................................................................7
2.3 Trust ...........................................................................................................................................................8
2.4 Normative evaluations ............................................................................................................................8
2.5 Instant gratification ................................................................................................................................9
2.6 SOR framework .......................................................................................................................................9
2.7 Correlations and Hypothesis development..................................................................................... 10
2.7.1 Normative referents and Trust ..................................................................................................................................... 10
2.7.2 Comparative referents and Trust ................................................................................................................................ 10
2.7.3 Normative referents and Normative Evaluation ................................................................................................... 10
2.7.4 Comparative referents and Normative Evaluation .............................................................................................. 11
2.7.5 Comparative referents and Instant Gratification ................................................................................................. 11
2.7.6 Trust and Impulse Buying ............................................................................................................................................. 12
2.7.7 Normative Evaluation and Impulse Buying ........................................................................................................... 12
2.7.8 Instant Gratification and Impulse Buying .............................................................................................................. 12
3. Research question and objectives ...............................................................................................13
4. Method.............................................................................................................................................13
4.1 Conceptual Model................................................................................................................................. 13
4.2 Research design..................................................................................................................................... 15
4.2.1 Quantitative methods ....................................................................................................................................................... 15
4.2.2 Questionnaire ..................................................................................................................................................................... 15
4.2.3 Participants and sample size ......................................................................................................................................... 18
4.2.4 Pilot experiment ................................................................................................................................................................. 18
4.2.5 Data collection procedure .............................................................................................................................................. 18
4.2.6 Statistical Procedure After the survey ....................................................................................................................... 19
5. Expected Results ............................................................................................................................19
6. Timescale ........................................................................................................................................20
7. Appendix .........................................................................................................................................21
7.1 Reference list.......................................................................................................................................... 21
2
7.2 Consent form ......................................................................................................................................... 29
7.3 Questionnaire ........................................................................................................................................ 30
3
Influence of Reference groups on Online Impulse Buying Behavior:
a Stimulus Organism Response framework
Trần Thị Kim Ánh, Nguyễn Lê An
Abstract
Based on Fisher and Rook’s research in 1995, this research applies the Stimulus
Organism Response framework to determine the influence of reference groups on
impulse buying. The study examines two reference groups (Normative referents and
Comparative referents) as two independent variables, working as stimuli and making an
impact on impulse buying behavior through three organisms, namely trust, normative
evaluation, and instant gratification. By adapting Exploratory Finding Analysis (EFA)
quantitative methods to analyze the sample collected from questionnaires, the research
is expected to provide a confirmation of the relationships between Normative referents
(family and close friends) and impulsive customers’ Trust and Normative Evaluation as
well as the correlations between Comparative referents (celebrities) and impulsive
customers’ Trust, Normative Evaluation, and Instant Gratification.
Key words: impulse buying; reference groups; SOR model; trust; normative
evaluation; instant gratification.
1. Introduction
Online shopping is a new trend in shopping behavior and has become a worldwide
prevalent shopping tool in recent years (Bùi, 2018). In Viet Nam, the proportion of
Internet users engaged in online shopping has increased from 77% in 2019 to 88% in
2020 (The White book on Viet Nam e-business, 2021). It is necessary for marketers and
business owners to have a deep insight into consumers’ online purchasing behavior.
Previous studies emphasized that three key aspects influencing consumers' impulsive
behavior were the ambiance, design, and social factors (Baker, 1987; Baker,
Parasuraman, Grewal & Voss, 2002). Reference groups - a social factor affecting
impulse buying behavior - are going to be thoroughly researched. Indeed, the use of
reference groups in an attempt to persuade people to make a purchase shows a belief
that these groups expose people to lifestyles and behaviors, have an impact on how they
develop their self-concepts, help shape their values and attitudes, and put pressure on
them to conform to group norms (Xiurong et al., 2010).
4
The research gap was noticed when most research in this field focused on impulse
buying behavior occurring in-store (Lu, & Su, 2018), not many proposed impulse
purchasing behavior on online platforms. Moreover, there are also many types of
classification of reference groups, but in this study, reference groups are divided into
two types: normative referents and comparative referents (Kelley, 1947). As we believe
that there is a considerable difference in the influence level of the two types of reference
groups, this study decided to scrutinize them separately as two independent variables.
Applying the SOR model is a new means to approach because most of the previous
papers use this model for environmental stimuli such as website design and online
feedback (Liu & Hu, 2013; Hong, Zulkiffli & Amran, 2021) rather than a social factor reference groups. To explain purchasing behavior, the Stimulus Organism Response
(SOR) framework is widely used, signifying the relation among (S) stimuli in the
environment (reference groups), (O) emotional states of people (trust, normative
evaluations, instant gratification), and (R) the behavior of approach or avoidance which
arises from the collaboration of stimuli and emotion (impulse buying behavior)
(Mehrabian and Russell, 1974). Therefore, this paper is to identify the moderating effect
of two specific types of reference groups as a social stimulus on impulse purchasing
behavior through three proven organisms: trust, normative evaluation, and instant
gratification.
The study intends to survey with questionnaire distribution to collect samples and
analyze the data by employing Exploratory Finding Analysis and other quantitative
methods. The result of this research is expected to provide a deep understanding of the
influence of reference groups which can be applied in marketing campaigns to create
experiences of families or friends (typical normative referents) or promote the use of
influencers, celebrities, or ambassadors (typical comparative referents) to persuade
people buying goods (Kotler, Armstrong, Saunders & Wong 1999).
In conclusion, impulsive shopping online has drawn a lot of attention from scholars over
the years. These researches, though, have not truly been focused on or exploited in
Vietnam. Therefore, the topic “Influence of Reference group on Online Impulse
Buying Behavior: a Stimulus Organism Response framework” will be researched
based on data collected in Ho Chi Minh city, which is known as a mega-city in Viet
Nam with a high population.
5
2. Literature Review
2.1 Impulse Buying
2.1.1 Definition of Impulsive Buying
The term “Impulse buying" was first used by Hawkins Stern in 1962 to emphasize the
phenomenon of “unplanned buying”: any purchase that a consumer makes and had not
been planned, with the decision made within a shop. In contrast to earlier research, the
study of Rook (1987) claimed that not all unplanned purchases are impulsive buying.
By the time, impulse buying is clearly defined as “a sudden, often powerful and
persistent urge to buy something immediately” (Rook, 1987. p. 191), which involves
affective components (Piron, 1991; Shiv & Fedorikhin, 1999; Weinberg & Gottwald,
1982) or hedonistic (Park et al., 2006). According to Block and Morwitz (1999), an
impulse purchase is one made by a customer as a result of an intense want that strikes
them suddenly and without much thought. Meanwhile, Kacen and Lee (2002) stated
spontaneous activity is less deliberate and more exciting than planned purchase
behavior.
As a result, with time, several dimensions were added to the definitions of impulse
purchase. However, this variation in "impulse buying" definitions highlights the need
for a more thorough investigation of the idea.
2.1.2 Online impulse buying
Based on the definition of impulse buying, customers extend their shopping
environment into online platforms. Piron (1991) described online impulse shopping as
an immediate, unplanned purchase made through the internet. We identified two distinct
conceptualizations of online impulse buying in this literature review. According to some
studies (T. Adelaar, S. Chang, K.M. Lancendorfer, B. Lee, and M. Morimoto, 2003),
online impulse buying is a hedonistic and unreflective process that lacks significant
cognitive reactions. However, other studies took cognition into account and highlighted
the importance of cognitive effort in mediating the connection between stimulus stimuli
and response (Y. Liu, H. Li, and F. Hu, 2013)
2.1.3 Factors influencing impulse buying
In the literature, the factors influencing impulse buying are divided into two kinds:
internal motivators and external motivators. (Xiao & Nicholson 2013). Internal
motivators refer to subjective factors, which possibly trigger consumers to engage in
6
impulse buying such as self-discrepancy (Sharpio, 1992; Muraven et al.,1998), multisensory, fantasy, and emotive aspects of an individual’s experience with products (Levy,
1959), mood state (Piron, 1989; Piron 1991; Elliott, 1994; Youn & Faber, 2000)); selfregulatory resource availability (Muraven et al., 1998), autistic stimuli (Malter, 1996),
and subjective well-being (Dittmar, 2008). Meanwhile, purchasing impulses can be
kick-off when a customer incidentally encounters a relevant visual stimulus in the retail
environment such as a collection of stores with a variety of products (Bloch et al., 1994),
physical proximity (Vohs & Faber, 2007), the anonymity of self-service environment
(Rook & Fisher, 1995). However, most of the above factors are only the trigger located
in the first phase in the impulsive buying decision-making process. In this research,
researchers do not consider related factors in a simple cause-effect correlation
relationship but put them in a model which explains the thorough process.
2.2 Reference group
A reference group is a group of people that has a huge impact on one’s behavior due to
psychological aspects (White, K. and Dahl, D. W., 2006). Social group members who
are psychologically significant to one's decision-making are referred to as the reference
group (White & Dahl, 2006).
In fact, consumers consider the recommendations made by others as a benchmark when
making purchases (Hwang, Mark, Jerry & Lin, 1999). When being unsure about
adopting an e-marketplace or having insufficient knowledge, e-vendors frequently turn
to informational reference groups to form a value standard and perception towards
products (Lee et al., 2011). Influential people's opinions are a significant determinant of
trust and commitment in relationships. When evaluating a difficult transaction platform,
the recommendation of the reference group frequently encourages e-vendors to adopt
and establish commercial relationships with the e-marketplace provider (Senecal &
Nantel 2004). Moreover, reference groups can intervene in customers’ needs and urge
them to impulsively make a purchase.
Though there are many classifications of reference groups named differently, this study
conclude them into two main groups based on their functions, impacts, and membership
status: normative referents (primary or direct membership groups) and comparative
referents (secondary or indirect aspiration groups) (Lessig & Park, 1978; Escalas &
Bettman, 2003; Kelley, 1974). Normative referents refer to reference groups to which
7
an individual currently belongs such as family and close friends. Meanwhile,
comparative referents are members of reference groups to which an individual desires
to belong such as sports heroes and celebrities. Besides the two main groups above, the
virtual community has recently become a significant potential reference group for
marketing because of its fast growth in popularity and influence. (Pentina, Prybutok &
Zhang, 2008). However, as it has not been widely accepted, it is not applied to this
research.
Even though there are many studies that have explored the classification of reference
groups or the influence of reference groups on customer behavior, there is no research
about the influence of reference groups on impulse buying behavior in which the
variables (normative referents and comparative referents) are examined independently.
2.3 Trust
Trust is defined as "the willingness of a party to be vulnerable to the acts of another
party based on the expectation that the other will perform a specific activity, regardless
of the ability to monitor or control that another party” (Mayer, Davis & Schoorman,
1995). Trust is related to convictions about the reliability, goodness, and competence of
the source (Jarvenpaa, Knoll & Leidner, 1998). The term "trust" describes the intensity
and certainty of feelings based on circumstantial evidence from the online marketplace
(McKnight, Choudhury & Kacmar, 2002). Trust is the cornerstone for establishing
enduring relationships in the context of an e-marketplace where business transactions
are private and results are uncertain (Hsiao, 2003). According to McKnight et al. (2002),
consumers' intentions to buy in various online store contexts are significantly impacted
by the trust since it reduces uncertainty. McEvily et al. (2003) state that trust functions
as a heuristic cue that can reduce the cognitive effort required when making decisions.
As pointed out by Jarvenpaa et al. (2000) and Sun and Wu (2011), trust influences
attitudes and risk perception, which in turn affects the intention to purchase in an online
business.
2.4 Normative evaluations
Normative evaluations are defined as consumers' assessments of whether making an
impulsive purchase in a specific buying scenario is suitable (Rook & Fisher, 1995).
Recent consumer polls have revealed that while the majority of customers do not view
their impulse purchases as being incorrect or wrong, a small percentage of consumers
8
feel regret and guilt after making them (Hausman, 2000). The Theory of Reasoned
action (TRA) acknowledged the idea of normative judgments and proposed that people's
acts are a reflection of their subjective norms (Ajzen & Fishbein 1977). Moreover,
Fishbein's Theory of Reasoned Action also points out that subjective norms stem from
people's expectations of how important social referents will respond to a considered
behavior and their motivation to do so.
2.5 Instant gratification
The level of immediate enjoyment that a person has after making a purchase is known
as instant gratification. Consumers have a widespread bias toward current rewards and
spending over future rewards and consumption, according to economists and economic
psychologists. Much economics literature discusses "time discounting" and "time
inconsistent" preferences (Lea et al., 1987; Hoch & Loewenstein, 1991; Lowenstein &
Elster, 1992). These researches, which used a range of methodologies, have
demonstrated that customers, on the whole, prefer having “one bird” in their hands to
having “two” or more offered at a later time, which means they prefer instant
gratification rather than receive more benefits but time-consuming. Therefore,
consumers with a particular personality type have an unquenchable demand for
immediate gratification prompts.
2.6 SOR framework
The SOR model was originally invented by Mehrabian and Russell (1974) in order to
analyze consumer purchases. This model includes three aspects: Stimuli (S) - the effect
of environmental cues, Organism (O) is an internal process or condition that results in
emotional responses. Response (R) is the outcome related to consumer behavior or
avoidance. This model seeks to incorporate individual reactions to describe how people
perceive and react to environmental stimuli. From there, conclusions regarding
consumer behavior are drawn. Stimuli are factors that are beyond a person's control and
have an impact on an organism's internal states when they are exposed to external
stimuli. An organism serves as a conduit for the connection between stimuli and
behavior, and it also controls the outcome of the reaction to the stimulus. The reaction
is a summarizing element in the reaction to outcomes for an organism's regulation.
Recently, the SOR model is not only used to discover consumer behavior in stores but
also to uncover online behavior. According to many researchers, the SOR framework is
9
applied in many fields to identify consumer behavior of online impulse buying (Chan,
Cheung & Lee, 2017), impulse buying in live streaming commerce (Lee, & Chen, 2021),
consumer online repurchase intention (Zhu, Kowatthanaku & Satanasavapak, 2020) or
brand-related user-generated content through Facebook (Aslam & Siddiqui, 2020).
2.7 Correlations and Hypothesis development
2.7.1 Normative referents and Trust
The suggestions of family and friends sparked business activity and promoted faith in
the website. More than anything else, people build trust based on the experiences of their
friends and relatives and place their confidence in their family (Hillman, Neustaedter,
Bowes & Antle, 2012). The primary, and sometimes the only, source of consumer trust
by people is family and friends. This demonstrates how each person is typically
impacted by their friends, coworkers, and family. Family recommendations or
suggestions are more significant in a person's life (AlArfaj, Solaiman & Marshall, 2019)
as well as purchasing behavior (Kotler et al., 2017). By catching the intention and
increasing the belief, these suggestions serve as efficient communication channels that
enhance the number of visitors to shopping websites and create opportunities for
customers to be exposed to environmental motivations.
H1a: Normative referents (family and close friends) have a positive impact (+)
impulsive customers’ Trust.
2.7.2 Comparative referents and Trust
According to studies, celebrity endorsements increase consumer trust in brands and
advertised products (Chen, Xie, Zhang & Li, 2021; Dwivedi & Johnson 2013; Takaya
2017). Because internet celebrities and regular consumers are more alike than their
traditional counterparts, their recommendations may seem more genuine and powerful
in fostering trust and boosting online sales (Hsu, Lin, Chiang & Sen, 2013).
H1b: Comparative referents (celebrities) have a positive impact on (+) impulsive
customers’ Trust.
2.7.3 Normative referents and Normative Evaluation
Family and other close relationships which are considered to be important social
subjects can impart norms, attitudes, and values through a lot of daily interactions.
Therefore, customers’ standards in terms of assessing and purchasing products are likely
to be heavily influenced by normative referents (Kelley, 1952). According to Li et al
10
(2008) study, people frequently follow key referents such as their family and close
friends while making decisions. Receiving disapproval from important persons
(particularly family or friends) can prevent consumers from making decisions to buy
when they are facing social risk. Moreover, people will make a comparison with the
social basis as the evaluation criteria if they lack objective standards to evaluate their
own attitudes and activities (Hwang, Mark & Jerry, 1999). There is pressure for
consumers to avoid buying item which is not in line with social expectations (Shang,
Pei & Jin, 2017). Therefore, realizing the important role of normative referents in the
process where customers form their individual standards aligned with social norms and
expectations to decide the appropriateness of products, researchers suggest the
hypothesis.
H2a: Normative referents (family and close friends) have a positive impact on (+)
impulsive customers’ Normative Evaluation.
2.7.4 Comparative referents and Normative Evaluation
Celebrities and brand ambassadors can be utilized as a reference for evaluating and
perceiving a brand normatively (Nofiawati et al., 2020). Most celebrities are seen as
representatives of the community, leading trends and embodying common standards of
the community. Arndt (1967) noted that consumers would heavily rely on other people's
recommendations when assessing new goods or services. The presence of products in
celebrities' daily lives or advertisements works as recommendations that their fans will
listen to (Kotler, Armstrong, Saunders & Wong 1999). Indeed, when celebrities can
advertise the product's benefits, buyers can realize the perceived value and have a better
assessment (Chi, Yeh & Tsai, 2011).
H2b: Comparative referents (celebrities) have a positive impact on (+) impulsive
customers’ Normative Evaluation.
2.7.5 Comparative referents and Instant Gratification
When promoting things to consumers, social media stars can incite feelings of envy,
which leads to purchases of the envied goods. Therefore, celebrities and ambassadors
who are well-liked and well-known will positively affect consumers' feelings and buying
intentions (Jin & Ryu, 2020; Brilliani et al., 2018). By the aforementioned definition,
consumers have the desire to be part of this inspired referent group (Kelley, 1974), so
they engage in similar behaviors like buying celebrity-like items. More than that, this
11
desire can be so strong that consumers want to achieve it immediately that forming
instant gratification.
H3: Comparative referents (celebrities) have a positive impact on (+) impulsive
customers’ Instant Gratification.
2.7.6 Trust and Impulse Buying
Trust can be an effective precursor for buying impulse behavior since buying impulse is
an irrepressible drive that is dominated by emotive rather than cognitive processes. The
emotive aspect of trust is associated with a willingness to take risks, whereas impulsive
buying is viewed as a "risky" decision that may lead to decision errors (Chen, Xie, Zhang
& Li, 2021). Trust can lessen the stress associated with impulsive behavior and enable
transactions in the face of uncertainty (Verplanken & Sato, 2011). In most impulse
buying studies using the SOR model, trust is suggested as a decisive organism when
examining a specific stimulus that leads to the response. This hypothesis has been
supported by some empirical studies in Viet Nam (Tuyet, 2019; Trung & Hà, 2017).
H4: Trust has a positive impact on (+) Impulse Buying.
2.7.7 Normative Evaluation and Impulse Buying
Impulsive purchase behavior is significantly and directly influenced by normative
evaluations (Lim, 2015). Reference groups can provide a normative function by
influencing people's standards (Kelley, 1952). Consumers will buy things impulsively
if they think that kind of goods is appropriate for them and live up to their satisfaction
and social norms (Ajzen & Fishbein, 1977). Moreover, normative evaluations in
different situations can both be positive and negative for a product, which means the
effect of impulse buying behavior will become excessive if there is the existence of
normative evaluation of impulse buying (Rook & Fisher, 1995). Therefore, researchers
suggest the following hypothesis:
H5: Normative Evaluation has a positive impact on (+) Impulse Buying.
2.7.8 Instant Gratification and Impulse Buying
Instant gratification positively relates to the urge to buy impulsively. Based on Youn
and Faber’s study (2000), instant gratification is the emotional state of customers have
when they make impulse buying. Impulse buyers boost their purchases right away when
they have instant gratification to their favorite goods (Liu, 2013). Youn and Faber (2000)
notice that there are important distinctions between impulse and non-impulse
12
consumers; an impulse consumer is more likely to act quickly and make decisions for
immediate enjoyment. According to in-store marketing wisdom, that allows them to feel
satisfied right away after making an impulse buy. Herabadi, Verplanken, and Van
Knippenberg (2009) show that there is a considerable association between the incidence
of these emotions and that impulsive purchases are frequently accompanied by higharousal feelings like excitement and enthusiasm. Impulsive buyers are driven by the
desire for the immediate gratification that shopping offers, which hedonistically boosts
their moods. Moreover, Cinjarevic and colleagues (2011) support the impact of hedonic
shopping incentives on impulsive purchasing behavior by their studies. To evaluate the
strength of the correlation, researchers scrutinize the following hypothesis:
H6: Instant Gratification has a positive impact on (+) Impulse Buying.
3. Research question and objectives
The research aims to evaluate the influence of referent groups on impulse buying by
applying the S-O-R model. To achieve this aim, researchers suggest two research
questions:
Through what organisms do normative reference groups affect impulse buying?
Through what organisms do comparative reference groups affect impulse
buying?
The research is conducted to reach three research objectives which, in turn, drive the
comprehensive research and structure the paper:
To describe “impulse buying” and “reference groups” in terms of their definition,
classification and characteristic.
To determine organisms resulting in impulse buying that reference groups have
a positive impact on.
To propose recommendations to marketers and business owners for promoting
impulse buying behavior of their customers by reference groups.
4. Method
4.1 Conceptual Model
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Figure 1. Proposed Conceptual Framework
To obtain the research objectives, the study proposes the conceptual framework using
the SOR model with six variables and eight hypotheses explained in the literature review
and scrutinized in statistical procedure. The hypotheses developed throughout the study
are stated below:
H1a: Normative referents (family and close friends) have a positive impact (+)
impulsive customers’ Trust.
H1b: Comparative referents (celebrities) have a positive impact on (+) impulsive
customers’ Trust.
H2a: Normative referents (family and close friends) have a positive impact on (+)
impulsive customers’ Normative Evaluation.
H2b: Comparative referents (celebrities) have a positive impact on (+) impulsive
customers’ Normative Evaluation.
H3: Comparative referents (celebrities) have a positive impact on (+) impulsive
customers’ Instant Gratification.
H4: Trust has a positive impact on (+) Impulse Buying.
H5: Normative Evaluation has a positive impact on (+) Impulse Buying.
H6: Instant Gratification has a positive impact on (+) Impulse Buying.
A number of techniques that have been developed use some fundamental theories and
models to analyze buying behavior in general and impulse buying in particular (Chan,
Cheung & Lee, 2017). There are some fundamental theories that can be initially
considered to be applied in this research, namely Theory of Reasoned Action - TRA
(Ajzen & Fishbein 1977), Theory of Planned Behavior - TPB (Ajzen, 1991), Technology
Acceptance Model - TAM (Gefen, Karahanna & Straub, 2003), The Unified Theory of
14
Acceptance and Use of Technology - UTAUT (Koufaris, 2002; Hoa, Tuan, Tung &
Huan, 2021) and chosen theory Stimulus Organism Response Model - SOR Model
(Chan, Cheung & Lee, 2017; Lee, & Chen, 2021).
Although many experimental studies have proven Theory of Reasoned Action and
Theory of Planned Behavior to be ultimate methods to investigate customer buying
behavior in online platforms (Thắng, 2016), they focus on the subjective and individual
motivations rather than an external one (Ajzen, Ieek and Martin, 1977). In addition,
Technology Acceptance Model and The Unified Theory of Acceptance and Use of
Technology, which are specially designated for online shopping, are inapplicable to the
study as they already include social influence as one of major variables in their models
without further organism explanation.
Meanwhile, because of a lot of beneficial characteristics presented in the literature
review, Stimulus Organism Response Model offers an effective way of assessing online
impulsive buying behavior. In this study, it is adopted to illustrate a comprehensive
mechanism to explain the proposed relationships of variables.
4.2 Research design
4.2.1 Quantitative methods
This research initially carried out empirical research to decide and understand the scope
of the study, research subjects and framework, then used quantitative methods to
examine proposed hypotheses.
There are some exploratory studies using both qualitative and quantitative methods to
determine the influence of reference groups on impulsive buying behavior. In order to
approach this topic, Lu and Su (2018) used quantitative methods and distributed 484
questionnaires, Xiurong and Chenglei (2010) conducted a survey of 286 graduates and
Chen, Wu, Lu and Chien (2013) surveyed 185 participants with questionnaires. As we
believed that empirical studies have successfully explored related concepts and
frameworks, this study does not need to use qualitative methods but only use
quantitative ones as a well-established approach to identify underlying variables and
evaluate the relationships between them.
4.2.2 Questionnaire
In the next phase, the researchers set up a questionnaire that applied the scale of
measurement and research items based on the consultants from the empirical studies.
15
The questionnaire was initially developed in English before being translated into
Vietnamese. In order to minimize the misunderstanding of respondents because of this
inconsistency in language, there is a pilot experiment conducted in the next phase.
The questionnaire has three sections to separately collect the information about
demographic characteristics of participants (gender, age, average monthly expenditure,
frequency of online purchases, time spent on browsing online group shopping websites),
popularity of impulse purchases among online group shopping users (consulted from the
questionnaire of Liu & Hu (2013)) and the test items.
1
2
Normative
Referents
3
4
Family and friends have a lot of useful experience
in online shopping.
Recommendation from family and friends is
trustworthy.
This
study
Information from family and friends is not reliable suggests items
(*).
My preference is often similar to that of my family
and friends.
1
Celebrity is good looking.
2
Celebrity is trustworthy.
3
Celebrity is reliable.
4
Celebrity is an expert.
5
Celebrity is qualified to endorse products.
1
I often buy spontaneously from online platforms.
Comparati
-ve
Referents
Impulse
2
Ohanian (1991)
I often buy from online platforms without
Rook & Fisher
(1995)
thinking.
buying
Beatty & Ferrell
3
I buy from online platforms according to how I feel (1998)
at that moment.
16
4
5
6
1
2
Trust
3
I carefully plan most of my purchases. (*)
“Buy now, think about it later” describes me while
purchasing from online platforms.
Sometimes I am out of control while buying from
online platforms.
I believe the online platform is trustworthy.
The online platform provides the recommendation
of products by customers preferences.
McKnight et. al
(2002); Gefen et
Using a credit card to make purchases from online al. (2003); Van
der Heijden et. al
platforms is safe.
(2003)
4
1
Normative
2
evaluation
3
1
Instant
Gratificati
2
on
3
My interaction with online platforms is pleasant
and enjoyable.
It is acceptable to buy 4 products that I like instead
of buying 1 as planned.
It's also fun to buy 4 products that I like instead of
Liu (2013)
buying 1 as planned.
It makes sense to buy 4 products that I like instead
of 1 planned product.
Purchase in online group shopping websites on an
impulse brings me immediate enjoyment.
Coley & Burgess
(2003); Gảdner
I would feel pleased when I purchase something on & Rook (1988);
an online group shopping website on an impulse. Rook
I would feel excited when I purchase something on
an online group shopping website on an impulse.
Rook & Gardner
(1993)
*Reverse-coded item.
Figure 2. The table of surveyed items and their sources of reference
17
(1987);
There are two reverse-coded questions to check the consistency of answers given by
respondents. Participants were asked to respond using a 7-point Likert scale ranging
from strongly disagree (1) to strongly agree (7) for questions in the third section of the
questionnaire. The reason for choosing this scale of question is that most of the studies
used as referent sources for the test items also employed 7-point Likert scale and showed
good reliability. Moreover, it is believed to be the most accurate scale with better
reflection of a respondent’s true evaluation.
4.2.3 Participants and sample size
There are 25 questions corresponding to 25 items above. With this number of questions,
the sample size in this study should be N > 50 + 8m to meet the requirement of EFA
(Exploratory Factor Analysis) (Tabachnick & Fidel, 1996). Therefore, researchers
expect to collect more than 300 questionnaires.
Respondents are supposed to be students at Foreign Trade University in Ho Chi Minh
City. They are living in an area that is the most modern one in Viet Nam with a crowded
e-commerce traffic for online shopping sites. At the age from 18 to 22, every participant
is expected to have direct personal experiences making a purchase online.
4.2.4 Pilot experiment
Once setting up a complete questionnaire, a pilot experiment is conducted for adjustment
if needed. The pilot experiment took place as a preliminary interview where researchers
exploit the point of view of 30 participants about online impulse buying behavior, get
them to fill in the questionnaire before discussing with them the questionnaire in terms
of its length, clarity and coherence. Following adjustments to the questionnaire, the
result collected from the pilot experiment is analyzed with the reliability test
(Cronbach’s Alpha) to evaluate the reliability or internal consistency of a set of scale or
test items and eliminate non-standard questions.
4.2.5 Data collection procedure
The questionnaire will be issued officially and carried out on Google Form tool for the
formal survey. The links will be shared on several social networking sites (such as
Facebook, Instagram and Zalo) and randomly emailed to students in Foreign Trade
University. The online form will include a consent part with a brief introduction to the
topic, an explanation of some terms and concepts, and a three-section survey question
part as presented above.
18
4.2.6 Statistical Procedure After the survey
Primary data will be statistically analyzed using SPSS software (version 20). After data
is put in the software, Cronbach’s Alpha and some other indexes (Factor loading,
Eigenvalue, Cumulative explained variance, Item to total correlation) required for
Exploratory Factor Analysis will be calculated. Once the sample is proven to be
acceptable, the Exploratory Factor Analysis method is applied to identify the underlying
relationships between measured variables presented in the proposed SOR model.
5. Expected Results
Compared with the minimum number calculated from the formula of Tabachnick &
Fidel (1996), the number of acceptable samples should be more than 250. In the
demographic characteristic part, the ideal result presents a balance between answers to
the questions about gender, age, average monthly expenditure, frequency of onlinepurchases and time spent on browsing online group shopping websites daily to illustrate
the diversity and generalizability of the observed sample. Notably, the questionnaires of
respondents whose answers are no browsing experience for online buying experience
will be automatically eliminated.
The resulting values are expected to satisfy the following criteria: Factor loading > 0.6
to ensure statistical significance of observed variables; Eigenvalue > 1 to determine the
total number of factors in EFA; Cumulative explained variance > 50% and Item to total
correlation > 0.5 to ensure the appropriateness of EFA model and not eliminate any
variables in the measurement scale, Cronbach’s Alpha > 0.7 to identify the reliability of
constructs.
After successfully investigating the sample by using Exploratory Factor analysis, we
desire to receive supporting results to prove that each sub-group in reference groups
(Normative referents and Comparative referents) still has positive influences on
dependent variables despite the classification. According to the hypotheses, Normative
referents (family and close friends) have a positive impact on impulsive customers’
Trust and Normative Evaluation. Also, Comparative referents (celebrities) have a
positive impact on impulsive customers’ Trust, Normative Evaluation and Instant
Gratification. Besides, as our research inherited all the items and scales from previous
empirical research to measure the correlations of three organisms (Trust, Normative
Evaluation and Instant Gratification) and Impulse Buying, we expect the result
19
supporting the hypotheses will help to elucidate the mechanism of influence of reference
groups on impulse buying through SOR model.
6. Timescale
Nov
The activity
2022
Dec 2022
Jan 2023
Feb 2023
Mar
2023
15 26 5 13 23 31 10 23 29 8 17 28 8 19
Writing research proposal
Reading literature
Finalize objectives
Draft literature review
Decide research approach
Draft research strategies
and methods
Review primary data
Organize the interviewers
Develop interview
questions
Conducting interviews
Analyse data
Develop questionnaire
Pilot test and revise
questionnaire
Administer questionnaire
Enter data into computer
Analyse data
Draft findings chapter
Update literature read
20
Complete remaining
chapters
Submit to tutor and await
feedback
Figure 3. Timescale for the complete study
7. Appendix
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7.2 Consent form
We are asking you to participate in a research study titled “Influence of Reference
Groups on Online Impulse Buying Behavior: a Stimulus Organism Response
framework”. We will describe this study to you and answer any of your questions. This
study is being led by Tran Thi Kim Anh and Nguyen Le An, students in Foreign Trade
University.
What the study is about
The purpose of this research is to determine the influence of reference groups on online
impulse buying.
In definition, online impulse shopping as an immediate, unplanned purchase made
through the internet and reference groups is a group of people that has a huge
psychological impact on one’s behavior which is divided into two groups: normative
referents (typically family and close friends) and compartive referents (typically
influencers, celebrities or ambassadors).
What we will ask you to do
We will ask you to answer three sections of questions to collect your demographic
characteristics, your behavior of impulse purchases online and some important surveyed
elements.
Risks and discomforts
We do not anticipate any risks from participating in this research.
Benefits
Information from this study may benefit other people now or in the future in terms of
understanding about consumer behaviours.
Privacy/Confidentiality/Data Security
We protect your confidentiality by not collect any identifying information at all (as in
anonymous surveys and just allow two researchers access to the data. However, Data
may exist on backups and server logs beyond the timeframe of this research project.
If you have questions
You can contact two researchers with questions or concerns A standard statement
follows:
The main researcher conducting this study is Tran Thi Kim Anh, student in Foreign
Trade University.
29
Please ask any questions through this contact Tran Thi Kim Anh at
kimanhtranthi24@gmail.com or at 0964118481.
Statement of Consent
If you have read the above information and consent to take part in the study, please click
on an “I approve” box below.
Thank you for your response.
7.3 Questionnaire
Section 1: Demographic Characteristics
Gender
0. Male
1. Female
Age
1. 18 years old
2. 19 years old
3. 20 years old
4. 21 years old
5. 22 years old
6. Over 22 years old
Average month expenditure
1. Under 3 million VND
2. 3 million to 5 million VND
3. 5 million to 7 million VND
4. Over 7 million VND
Frequency of online purchases
0. Have never purchased online
1. Once to twice a month
2. Twice to four times a month
3. More than four times a month
Time spent on browsing online group shopping websites
30
0. Have never browsed online group shopping websites
1. Under 30 minutes per day
2. 30 minutes to 1 hour per day
3. 1 hour to 2 hours per day
4. More than 2 hours per day
Section 2: Evaluating popularity of impulse purchase among online group
shopping users
Please recall your last purchase in online group shopping sites, was the purchase
decision made suddenly when you were wandering in the online group shopping
websites, or made before you start to browse the website?
Options
1. I have never purchased using online group shopping sites before.
2. I have already had a specific shopping goal before I start to browse the websites.
3. My decision was made suddenly when I was wandering around on websites.
4. None of the above options describe me.
5. I do not remember.
Section 3: Specialized questions to investigate test items
Please choose your answer from (1) Strongly disagree to (7) Strong agree according
to your level of approval.
Family and friends have a lot of useful experience in online shopping.
Recommendation from family and friends is trustworthy.
Information from family and friends is not reliable.
My preference is often similar to that of my family and friends.
Celebrity is good looking.
Celebrity is trustworthy.
Celebrity is reliable.
Celebrity is an expert.
Celebrity is qualified to endorse products.
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I often buy spontaneously from online platforms
I often buy from online platforms without thinking.
I buy from online platforms according to how I feel at that moment.
I carefully plan most of my purchases.
“Buy now, think about it later” describes me while purchasing from online platforms.
Sometimes I am out of control while buying from online platforms.
I believe the online platform is trustworthy.
The online platform provides the recommendation of products by customers
preferences.
Using a credit card to make purchases from online platforms is safe.
My interaction with online platforms is pleasant and enjoyable.
It is acceptable to buy 4 products that I like instead of buying 1 as planned.
It's also fun to buy 4 products that I like instead of buying 1 as planned.
It makes sense to buy 4 products that I like instead of 1 planned product.
Purchase in online group shopping websites on an impulse brings me immediate
enjoyment.
I would feel pleased when I purchase something on an online group shopping website
on an impulse.
I would feel excited when I purchase something on an online group shopping website
on an impulse.
32