Factors affecting the impulse shopping intention of Vietnamese people: An application case in Ho Chi Minh City

The main purpose of this study is investigating about Vietnam customer’s behavior in term of impulsiveness and all related factors that have influences on the main variable by searching and reading the various previous studies in the field of Retailing and Consumer Behavior. To be more specific, this research employed a quantitative approach to find out the impact of six factors Sale Promotion, Presence of Family and Friends, Emotion, Money Available, Merchandise Display and Festival Season by using some analysis tools including descriptive statistics, reliability, factor analysis, correlations, and multiple regressions. Based on the findings of this research, Money Available and Emotion are the dimensions that eliminated while Sale Promotion is the factor that stands the highest influence on the Impulse Buying Behavior of customers. In general, numerous dimensions both internal and external have been analyzed with the aim of helping the researcher figure out an evaluation and judgments towards Impulse Purchasing as well as contributing to the knowledge of the world in term of customer behaviors. Finally, yet importantly, some recommendations have shown to guide the retailer to enhance their sales and performances.


Introduction
*After more than ten years since 2007 joining in the World Trade Organization (WTO), the retail market in Vietnam becomes one of the most dynamic, growing, attractive markets in ASEAN. The government has fully opened Vietnam market for both domestic and international cooperation especially in the retail industry. There are many different international retail groups have entered in Vietnam market and the number of domestic as well as foreign supermarket incline in many large cities in Vietnam such as Ho Chi Minh city, Hanoi city, Da Nang city and so on.
In the last five year, this figure in Vietnam had a tendency to decline but it predicted to increase to 6.5% in 2018, which is higher than the previous year 2017 with just 6%. To be more specific, the reason for this growth is the incline demand of customers who always want product with high quality and reasonable price.
To be more precise, nowadays, people usually go to supermarket rather than the traditional market due to the requirement of hygiene, good quality and trusted source products.
Furthermore, increase in income per month of citizens definitely lead to a growth in spending of them. The customer expenditure in Vietnam rose to 157.2 US$ billion in 2017 and is predicted to grow to more than 180 US$ billion in 2020. Alternatively, an increase in consumer spending means that the customers nowadays are willing to buy more, leading to a change in purchasing behaviors. In order to get more attentions from the clients, most of key retailers in Vietnam especially in Ho Chi Minh City such as Co.opMart, Aeon Mall, E-mart, and so on; not only perform the best marketing strategies, but also need to find out more information and have a deep knowledge about the psychological issues including the impulsive behavior. If any retailer does not have understanding about the customer behavior and cannot follow the demand of customers, they can be eliminated in the industry.
Spontaneous purchasing has been became one of the most vital problems that need to investigate and analysis more for all of researcher in the world. It is no doubt that each customer has suffered this type of buying at least one time in his or her lives. To be more specific, it is about nine out of ten purchasers make an unplanned buying at infrequent. Moreover, Wang et al. (2014) mentioned the negative results relevant with impulse buying behavior in a study investigating about Vietnamese inhabitant disappointment with this type of buying even though they have not experienced it before.
Furthermore, most of the investigation about impulse buying behavior is for the western culture. There is a lack of investigation regarding impulse purchasing behavior of consumers in the Asian countries/cultures especially in Vietnam such as "Impulse buying behavior of Vietnamese consumers in supermarket setting" by James Cho and partners or "An Exploratory Investigation into Impulse Buying Behavior in a Transitional Economy: A Study of Urban Consumers in Vietnam" of Mai et al. (2003).
Moreover, there are many researchers demonstrated the importance of understanding unplanned purchasing behaviors. For example, Hausman (2000) said that this type of buying is extremely difficult to understand which will create a huge amount of good sold annually. Another study illustrated that there is a need to pay more attention on the spontaneous buying in developing countries rather than developed nations (Kacen and Lee, 2002).
Additionally, due to the development in marketing and PR aspects leading to the modification in the marketing environment, it is unavoidable that the impulse buying will occur, especially in most of Vietnam cities.
To sum up, impulse buying behaviors is one of the most difficult and essential psychological issues to understand. So that why the conduction about consumer behavior in Vietnam market is necessary, which not only help the retailers, can gain more profit, but also the consumers are more conscious with their behaviors.

Literature review
To begin with, it was consider as interruption of normal purchasing process (Stern, 1962) while in the research of D' Antoni and Shenson (1973) illustrating that depended on the speed of buying goods of customer, retailer can definitely define what types of consumer behavior including spontaneous purchasing.
In addition, the root of impulse purchasing is from a decision to purchase of customer when entering into the supermarkets or the stores (Bellenger et al, 1978). Another finding about this topic is that the intensive time such as high emotional encouragement or low cognitive control, the clients influenced by the surrounding environment and would buy more products than daily routine (Weinberg and Gottwald, 1982). Moreover, Rook said that it was one type of psychologist conflict in his research 33 years ago.
Considering everything, numerous researchers typically essentially characterized motivationpurchasing conduct as unplanned buying behavior. (Rook, 1987) has left a historic point in the field of research on it by outlining the past ideas and giving it a shiny new portrayal.

Factors affect impulse buying behavior of customers
First, according to Zhou and Wong (2004), some factors including discounted in price definitely affect the amount purchasing of customers. To be more specific, there are two main kinds of sale promotion, price discount and price reduction which mentioned in the research of Dholakia (2000) with their coworkers in 1998 and 2006. There are numerous evidences showing that the purchasing amount of customer boosted significantly when experiencing product special discounts or promotional activities (Dholakia, 2000). H1: Sale promotion affects the impulse buying behavior of customers.
The second factor that will have an impact on impulse buying behavior is the appearance of companions when going shopping. Aninvestigation of Zajonc (1965) mentioned that the presence of other people was considerably changing the normal buying behavior of customer in the positive way especially when partners have close-knit relationship with them such as family, friends or coworkers. Moreover, another conclusion of the previous researcher was that the desire of shopping partners as well as the supported or rejected point of views of them could affect the amount purchasing of customers significantly.
H2: Presence of family and friends affects the impulse buying behavior of customers.
Thirdly, the factor that mentioned most of time in the previous study of many investigators is the mood that customers feel when they were in shopping trip. Park et al. (2006) mentioned it exists a positive relationship between emotions of customers with their buying behaviors especially impulse buying intention. Furthermore, Beatty and Ferrell (1998) and Roger and Paul (2000) as well as Youn and Faber (2000) also had the same conclusions about the positive relationship between the feeling of customers and their purchasing behavior in their researches. Moreover, another similar conclusion showed that person who wants to boost their feeling would definitely buy product more impulse.
On the other hand, there was also some argument about the connections between the feelings of customer and their purchasing behaviors. To be more precise, Sneath et al. (2009) demonstrated that the buying amount would be decline if customer witnessed depression in their mood.
H3: Emotion affects the impulse buying behavior of customers.
The display of products is one of the best ways for supermarkets or grocery store to attract the attention of customers. According to Grewal et al. (1998), the main purposes of attractive merchandise display are not only bringing the good image and reputation of supermarkets to the customers but also boost the purchasing amount of customers.
Furthermore, according to Ghag (2013), it illustrated that the amount buying of customers relied on the way that retailers use to show products in stores.
H4: Merchandise display affects the impulse buying behavior of customers.
Incomes of customer also play an important role in customer behaviors (Abratt and Goodey, 1990). To be more specific, some factors such as money available also be was showed in the research of Dittmar and Drury (2000) which researched about the impulse buying tendency of customers. Furthermore, it is undeniable that only clients who have high income than the others can afford the spontaneous buying because they always have large amount of budgets.

H5: Money available affects the impulse buying behavior of customers
Vietnamese citizen have experienced many festival season annually. Particularly, in these periods, people usually gather in order to hold a party and enjoy the relaxing time. Hence, this is a great opportunity for supermarkets and grocery stores to boost their sale by decorating their store relevant with the holidays as well as import much stuff that have and seasonal context in their displays.
H6: Festival season affects the impulse buying behavior of customers. Below is the model framework ( Fig. 1), which the researcher will use to check the validity and reliability of six hypotheses:

Primary data
Primary data collected by survey in the form of questionnaire. Not only had the paper questionnaire used to get the answer of respondents but also the online form. To be more specific, the online survey was more preferred because of its advantage that reached the large number of survey takers in short amount of time. To be particular, the online survey made through the link of Google Form and spread out in the social media channel of the researcher in order to increase the number of respondents as many as possible. Besides that, the paper questionnaire were also distributed in International University to reach the buyers who are students as well as in supermarkets such as Co.opmart, Big C and so on so that the types of survey takers can extend more housewife.

Secondary data
In order to find out the research gap and research issues of the questionnaire, before spreading it to large amount of people, the pilot test used when receiving about 50 respondents. The respondents who have experienced shopping in supermarket were chosen to raise the reliability and validity of the questionnaire. By using the SPSS software, the researcher has found some problems and irrelevant items in each factors resulting to reconstruct the questionnaire in order to get better result.

Sampling
People who have the following characteristics: living in Ho Chi Minh and especially have experiences of going shopping at least once time in their life chosen to conduct this thesis paper.
To be more specific, there are several methods that can be used to collected data but offline and online survey was used in this investigation to reach total 271 respondents.
First, for the online channel, an online survey, which was created through Google Form, was distributed through social network channel of researcher like Facebook. Moreover, after more than 1 week of spreading, there were about 170 answers from online channel. Besides that, the remaining conducted in International University as well as some popular supermarkets in Ho Chi Minh City. Particular, while joining into 2 classes of Dr. Nguyen Nhu Ty at International University, the total number of responses increased to around 250 immediately while just only 20 answer from were collected from people who were at supermarkets such as Co.opmart, Big C due to the difficult situation to interrupt them for completing the questionnaire when still at shopping.
In general, it took about more than 2 weeks for the investigator to reach 271 respondents and move to next step.

Pilot study
Pilot was conducted in order to testing the reliability and consistent of the questionnaire. To be more specific, 40 sample answers collected through approaching students from Business Ethics class of Dr. Nguyen Nhu Ty at International University as well as a part of total respondents is from classmates of researchers. In other words, pilot study was process after having more than 50 respondents.
Thanks to this, this test, help the investigator to have an overview about the questionnaire as well as recognize some items that are not relevant with the factor and can affect the result in negative ways. The survey redesigned with some modification in term of items in order to gain the better result.

Age
The pie chart (Fig. 2) witnessed that most of participants of this research taken in the range of 18 and 35 years old, at 84%. As can be explained, people from 18 and 35 years old usually pay more attention on trending and promotion events organizing in supermarkets. In addition, the 18-35 aged groups also spontaneously buy products more than other groups due to the financial budgets.

Income
The data demonstrated four levels of income having closely percentage of the target respondents. In term of people having income from 2 to 5 million VND per month, there was the largest segment at 32%. The next following positions were the group of income less than 2 million VND and from 5.1 to 10 million VND, at 28% and 23% of total survey-takers respectively. Finally yet importantly, the highest income per month was the smallest proportion, at only 17% (Fig. 3).

Gender
The pie chart (Fig. 4) showed the percentage of the respondents of both genders in the investigation. As can be seen from the graph, the rate of female is higher than male by 34%. It concluded that women were the main target respondents of this research due to the fact female often went shopping more than male.

Occupation
Because of the limitation of time and people participating in the investigation, the proportion of students stood in the first position of the whole respondents, at over 70%. The next position belonged to officers, at 19%. Additionally, business owners and homemaker shared the same position in the chart, both at 4%. Finally yet importantly, the percentage of other jobs was not significant at only 1% (Fig. 5).

Dependent variable
It can be easily seen in the Table 1 of Cronbach's Alpha above, this figure of dependent variable -Impulse Buying Behavior is 0.733 which is definitely greater than 0.6 -the standard value. Hence, it concluded that the scale had high internal consistency reliability. Furthermore, there was no sub-factor that need to delete in the research regard to all of Corrected Item-Total Correlation of 5 items were greater than 0.3 (Table 1).

Independent variables
As shown in the Table 2, the Cronbach's Alpha of all six variables is higher than 0.7 and the corrected items total correlation have the lowest value at 0.28. To be more specific, the Crobach's Alphas of (Sale Promotion, Presence of Family and Friends, Emotion, Merchandise Display, Money Available and Festival Season) are 0.769, 0.75, 0.802, 0.863, 0.797 and 0.85 respectively. The result illustrates that none of the independent factors has poor internal consistent reliability as well as all of six dimensions can be keep to make further analysis for the research to investigate about the relationship between independent variables and dependent variables. Moreover, the significant relationships between items also mentioned through the high Cronbach's Alpha.

Exploratory factor analysis
To be more specific, SPSS software within Varimax rotation in the sample of observations used in this study with the purpose of demonstrating the results of Barlett's test of sphercity and Kaiser-Meyer-Olkin (KMO) test in particular. Considering into the standard value of both testes, sig. value of first test should be lower than 0.05 while the KMO value should be greater than 0.6 to be consider as acceptable (Nguyen and Tran, 2017). Besides that, the factors cannot be disregard when they have the Initial Eigenvalues are higher than 1.

EFA for dependent variable
As shown in the Table 3, all of five items of Impulse Buying Behavior are located tin only one component.
Two important numbers that we need to pay attention in Table 4 and Table 5 were KMO value and loading cumulative percentage. To be more specific, the first figure is 0.751 which is higher than 0.5 -the standard level while the cumulative loading showed that the five items loaded for 48.648% in total.

EFA for independent variables
After conducting 4 rounds with deleting PP2, SP4, SP5, SP6, we get the final result as below (Table 6).
In conclusion, after running the final round of EFA, KMO value witnessed a slightly decrease from 0.843 in the second round to 0.825 but this result is still valid by comparing with the standard value which is 0.5. Additionally, in the Table 8, the cumulative percentage of six components was shown at 65.162 which meant that total 6 components containing 24 items accounted for 65.162% of Impulse Buying Behavior which was higher than 4.632% in comparison with this value of the first round (Table 7 and Table 8).

Correlation testing
The purpose of Correlation Analysis is to investigate the closeness of the relationship between two variables and more. As shown in the Table 9, SP and IB have the strongest positive relationship with each other (r = 0.697). Nevertheless, the Pearson correlation value between MA and IB is -0.064 which results that there is no linear connection between these dimensions. As consequences, Money Available factor eliminated out of the scale before conducting further analysis.

Regression analysis
For regression analysis, R Square value shows the percentage of influence that independent variables can affect the dependent variables. To be more specific, in this investigation, after running regression analysis, R Square was 0.726, which means five independent dimensions that are Sale Promotion, Presence of Family and Friends, Emotion, Merchandise Display, and Festival can interpret 72.6% of the variance within the Impulse Buying Behavior. Besides that, the ANOVA table displayed the Sig. equal to .000 which is less than 0.05, the standard level, implied that the research model was statistically substantial. The main connection between Impulse Buying Behavior and five main factors is illustrating in this study. From the Table 10, it informs that sig. value of four of five factors are less than 0.005 while only sig.
value of Emotion (EE) is 0.056 greater than 0.005 which can be considered as unacceptable and exist no relationship with the dependent variables (Table  10). Pay more attention on the factors that have influences on the Impulse Buying Behavior of customer. First, Sale Promotion factor stand the topmost position in comparison with other with 0.348 in unstandardized coefficients column. In other words, this factor is responsible for 34.8% of spontaneous purchasing tendency of customer. Besides that, following are the existence of family and friends as well as festival season factor; they are responsible for 33.6% and 22.2% respectively in modifying the buying behavior in term of spontaneous. Finally yet importantly, Merchandise Display is the variable that have least influence on increasing the amount unplanned purchasing of clients with just 18.4% in total.
All of values in VIF and tolerance in this investigation does not over the standard rules (<10) which mean it does not contain any connection as well as influences between any independent variables with the others.
After all consideration, the below regression model was created based on the unstandardized coefficient beta which show all of percentage that independent variables effect on the main subject of this investigation which is Impulse Buying Behaviors: IB = 0.184*MD + 0.222*FS + 0.348*SP + 0.336*PP In conclusion, the research model in Fig. 6; shows four dependent components that kept for the study.

Discussion
To sum up, the result is partly similar comparing with the first the hypotheses and the proposal framework. To be more detailed, the finding demonstrated the positive influences of 4 factors: Sale Promotion, Presence of Family and Friends, Merchandise Display and Festival Season on the spontaneous purchasing intention of customer. On the other side, two remaining variables from the proposal framework which are Emotion and Money Available are concluded that it do not exist any relationship with or create any impact on the dependent variable-Impulse Buying Behavior.
Taking the deep into the finding of this investigation, first, Hypothesis 1-Sale Promotion is the strongest impacted variable. The reason why this factor stood in the first position is that based on the psychological aspect, people always are attracted when they see any products that have cheaper price when comparing with the normal price. Besides that, the main occupation of respondents in this research are students who come from many university in Ho Chi Minh, it is undeniable that students always want to purchase products with cheaper price because they have desires to save their budgets as much as they can. As a result, if the retailer wants to boost their sales, they should not only focus on numerous types of products but also need to run many promotion programs with special discount on their products to gain the attention of customers.
Moreover, second position is belonged to the Presence of Family and Friends factor with 33.6% affected on the impulse buying behavior. It can be said that most of customer agrees that if they have a friends or a relative to go shopping with them, they will have a tendency to purchase goods and products more than expectation. To be more specific, the existence of peers will help them enjoy the surrounding environment in the supermarket and grocery, which definitely leads to increase for time that they use to walk around the supermarket. Finally, the last two factors, Merchandise Display and Festival Season, are responsible for about nearly half of percentage influenced on the unplanned buying behavior of shoppers. It means the buyers should build the strategy based on development of attractive and eyes-catching products in order to gain more customers purchasing shortly. While for the festival season factor, it can easily understand that in some special holidays such as Tet holiday, New Year Eve, Christmas and so on, the emotion of people boosted a lot because of the happy and clamorous surrounding environment. Hence, customer will be significantly pleased to spend more amount of money on buying products as well as stuff for not only themselves but also their family. In conclusion, with the aim of inclining the impulse purchasing of customer, retailers also need to import many products and goods that are useful for the specific holiday or contain the meaningful decoration related to special season or events.

Benchmarking
The main objective of this study is to find out some factors, which may have relationships with some factors to the impulse buying behavior. Compared to other previous research studies, this may give out more precise evaluation in the context of developing countries and emerging market like Vietnam, which then affect to the decision to invest in Vietnam of larger and international retailing corporations. The consequences of this research may give more in-deep and valuable insights of researching customers' behaviors, especially impulse buying intentions of customer when going to supermarkets and grocery.
More precisely, an important finding of this research is that it still exists the relationships between six factors such as sale promotion, presence of family and friends, merchandise display as well as festival season and the dependent variable. Regard to result of this research with most of participants are students, sale promotion stands the first place in term of changing their buying behavior to purchase more products, which are not exist in their plans. On the other hand, the result of factor Emotion and Money Available was not good as others as consequence of dissatisfied Sig value. Therefore, it does not play a significant role in the research, which means that there are no relationship between them and Impulse Buying Behavior.
Although there are many issues as well as problems that need to be consider in the whole world in the present day, spontaneous purchasing behavior has been become one of the most concerns for market researchers. According to Hausman (2000), he said that spontaneous purchase is an extremely complicated and convoluted phenomenon, which contributes a large number of goods that sold annually in every supermarkets as well as grocery stores in the world. Moreover, there are many investigators about clients pay more attention on understanding the various variables that can make an impact on some special behavior of customer such as impulse buying behavior (Bayley and Nancarrow, 1998).

Acknowledgement
The author would like to thank Ms. Nguyen Huong Giang from School of Business, International University -Vietnam National University, HCMC for her editorial assistance.

Conflict of interest
The authors declare that they have no conflict of interest.