INTENTION TO PURchASE PRODUcTS UNDER VOLUME DIScOUNT SchEME: A cONcEPTUAL MODEL AND RESEARch PROPOSITIONS

Many standard brands sell products under the volume discount scheme (VDS) as more and more consumers are fond of purchasing products under this scheme. Despite volume discount being commonly practiced, there is a dearth of research, both conceptual and empirical, focusing on purchase characteristics factors and consumer internal evaluation concerning the purchase of products under VDS. To attempt to fill this void, this article develops a conceptual model on VDS with the intention of delineating the influence of the purchase characteristics factors on the consumer intention to purchase products under VDS and provides an explanation of their effects through consumer internal evaluation. Finally, the authors discuss the managerial implications of their research and offer guidelines for future empirical research.


Introduction
In marketing research, sales promotion (SP) plays a vital role not only for the benefits of consumers but also for the manufacturers to increase their volume of business, and, simultaneously, nurture new consumers of the products. A large proportion of the marketing budget is spent on sales promotion. However, most of the SP activities fail and are unable to fulfil the retailers' goals ), due to the retailers' lack of knowledge concerning different types of promotion and the appropriate conditions for use. The inappropriate application of sales promotions may lead to a reduction in the likelihood of a brand and product being chosen (Campo, Yague 2007). Therefore, the retailers are interested in finding possible ways to predict the effectiveness of selected SPs to increase consumer in tention on purchasing decisions (Laroche 2002).
There are different types of SP available in the market. While the research on price discount has been extensive (Neslin, Shoemaker 1989;Chang et al. 2011) and the crucial dimensions of price discount in several contexts have been studied, the research on nonprice promotions (volume dis count) is very limited (Carpenter, Moore 2008). Under the volume discount scheme (VDS), the retailer or manufactu rer rewards those purchasing in bulk or by unit by providing a reduced price for each product or group of products, e.g. 5% (or more) extra, buy one (or more) shirt(s) and get one (or more) free, buy one and get one with 50% discount, and coupons that can be exchanged for an extra volume on repurchase. All over the world, the sales promotion under volume discount is commonly practiced as more and more consumers are becoming fond of purchasing products un der volume discount. Jayaraman et al. (2013) showed that VDS is one of the most common sales promotion tactics at BusinesstoConsumer (BtoC) level in Malaysia. A sales promotion that is effective for your competitors may not be effective for your brand or store and a promotion that works for a product, may not work for other products. Sinha and Smith (2000) found that volume discount is an effective way to promote storable products. However, contrary to Sinha and Smith (2000), Li et al. (2007) found that there is no relationship between the storability of pro ducts and the intention to purchase products under VDS. This is a real motivation for developing a conceptual fra mework to make it possible to test the direct and indirect relationship of factors (causeeffect) that influence VDS sales promotion.
From the consumers' point of view, SPs are more than just moneyoff. Raghubir and Corfman (1999) pointed out that consumers judge the quality of a product based on the depth of promotions. Further, Inman et al. (1990) and Raghubir (1998) remarked that, in general, SPs may mislead the consumers on the price image of the product as the product is sold at a lower price during the SP period. Therefore, it is essential to conceptualize the stimulus and situations that may create the real perception of quality and monetary savings when the product is promoted, especially under VDS.

Background on general framework of sales promotion
The majority of the research studies conducted before 2000 included the factor monetary savings while con ceptualizing the framework, and claim that it is the only benefit of SP to the consumers (Chen et al. 1998). The as severations of these studies raise a question: can monetary savings alone completely explain the consumer response behaviour to the SPs? If so, then everyday low price ta ctics should be successful in any store, brand, and on any products due to minimizing the search cost to the consu mers. Nevertheless, previous studies have found that the everyday low price tactic cannot fully replace SP strategies (Hoch et al. 1994;Lal, Rao 1997). If not, what other con sumer perceptions of the benefits of SPs affect consumer evaluation? Towards this, Chandon et al. (2000) proposed a research framework of the multiple consumer benefits of sale promotions. They categorized the benefits of SPs to the consumers as utilitarian benefits (savings, higher product quality, and improved shopping convenience) and hedonic benefits (value expression, entertainment, and exploration). They found that nonmonetary promotions (free gift and sweepstake) provide more hedonic benefits and fewer utilitarian benefits than monetary promotions (price cut and free product). Therefore, they concluded that monetary promotions should be more effective for utilitarian products whereas nonmonetary promotions should be more successful for hedonic products. Palazon and Delgado (2005) demonstrated that nonmonetary promotion is also appropriate for utilitarian products as it generates empirical benefits. Raghubir et al. (2004) extended the ideas of Chandon et al. (2000) and constructed an integrated SP model to as sist marketers to design SP more efficiently as well as more effectively. The researchers considered additional utilitarian and hedonic benefits and explicitly address the informative effects of SP. In their research model SPs have three aspects; namely, economic, informational, and affective aspects. An economic aspect of SPs is that they generate monetary economic drivers and nonmonetary drivers, such as make purchase decision cheaper, easier, and save searching time. Informational aspects refer to consumers' use of promotion as an informational tool to infer the quality and price of promoted products or as a reminder. The affective aspect of SP implies to the positive and negative consumers' feelings about their shopping deal. The findings reveal that the in formative and effective aspects of SP offers are different and they can boost or diminish the attractiveness of the offer beyond the economic aspects of the SP.
The initial studies on sales promotions proposed by Chandon et al. (2000) and Raghubir et al. (2004) concep tualized the management models in general. Both models are related to sales promotions and do not focus on volume discount. In fact, the definitions and measurement of va riables differ for different types of promotion as the nature of the promotions are different. Chandon et al. (2000) con sidered a reduction in search and purchase decision cost as relative factors of perceived convenience. In fact, these factors are more appropriate for price discount than VDS. Moreover, there are other factors like reduction in shopping trips and minimizing the time of purchasing through fe wer trips that are not taken into account by Chandon et al. (2000), which are obviously essential to the study of VDS. Hence, it is necessary to have a special conceptual model for each sales promotion, and, accordingly, the present study concentrates on VDS. In addition, they did not consider the effect of situational factors in their models, which can affect consumer intention and their decision to purchase products under SPs. If situational factors, such as store type, brand type, and product category affect consumer intention to purchase products under VDS then a key managerial implication is that retailers get to know the expectations and needs of the consumers.

Development of the research model
The current study uses literature review and interview, to identify the factors that related to volume discount. Chandon et al. (2000) proposed six benefits of sales pro motion that actuate the consumer to respond to sales pro motion. However, there is no literature to indicate which of these six benefits are related to volume discount. Based on the structured personal interviews with 50 Malaysian con sumers, the perceived savings, perceived quality, perceived selfexpression value, and perceived convenience were found to be internal evaluation factors that Malaysian con sumers consider when encountering volume discount sche mes. The purchase characteristics of VDS (Independent variables) are explored through metaanalysis on perceived savings (Appendix I) and perceived quality (Appendix II). A second interview was conducted with 30 respondents who have experienced the purchase of products under VDS to select the most important variables for the purchase cha racteristics of VDS and to develop the measurement items for new constructs.
The initial conceptual framework was developed ba sed on the literature review and interview. The concep tual framework, as presented in Figure 1, posits that the purchase characteristics of VDS like product category, brand image, store image, scheme characteristics, message framing, and subjective norms influence the consumer internal evaluation of benefits. The link between purchase characteristics of VDS and consumer internal evaluation of benefits is mediated by consumer internal evaluation of the benefits; namely, perceived savings, perceived quality, perceived selfexpression value, and perceived convenience.
In order to enrich the research framework and to have new inputs, some experts in the Malaysian consumenr mar ket (BusinesstoConsumer) were interviewed. Since the literature on sales promotion particularly under volume discount scheme is not researched that much , the marketing expert views were helpful in va lidating the model variables and their relationships on the consumers' intention to purchase products under VDS. Towards this, eight interviews were conducted by super visors and managers of major shopping malls of Malaysia which includes Tesco, Giant, AEON, AEON Big, Sunshine, and Cold Storage. The interviewees also confirmed the im portance of considered variables and relationships in un derstanding consumers' response to VDS.
The links between variables are supported by the StimulusOrganismResponse (SOR) model (Bagozzi 1986). The justification for using the S-O-R model in the present study is the relevant theoretical support extended to examine how marketing stimulus affect consumer in tention to purchase products under VDS. The researchers (Mummalaneni 2005;Kim et al. 2009) have applied the S-O-R paradigm to predict consumer purchase behaviour and the findings supported its applicability. Secondly, the application of the S-O-R model has the strength of exter nal stimulus and internal processes at the same time. The SOR model proposes a linear relationship between the three stages of environmental and social stimuli, which act as an external cause to the organism. This approach assumes that stimuli can affect an inactive and unprepared organism (Eysenck, Keane 2000). However, nowadays, most modern theorists assume that information processing is led by an active organism whose past experience influences not only the processing of such information but even what informa tion is sought and received. The information processing is both stimulus driven and concept driven (Moital 2006). In the present study, the consumer's brand image, store image and subjective norms realized from the consumers' past experience are considered in addition to external stimulus, such as product category, message framing, and scheme characteristics. These variables are supported by the recon ceptualized SOR theory developed by Jacoby (2002) and remove the limitations of the SOR theory. Krishna et al. (2002) found in their study, less consistent, small and plausible deals, presence of regular price, deals in nonfrequent discount stores, and deals on national brand yield higher perceived savings. They found that presen ting a regular price as an external reference price reduces Fig.1. A volume discount scheme model perceived savings when the deal percentage is extremely large. Sinha and Smith (2000) found that the consumers perceived significantly higher transaction value from the extraproduct promotion (buy one, get one free) than the mixed promotion (buy two, get 50% off). The reason that the "Buy two, get 50% off " deal is perceived so poorly vis àvis "Buy one, get one free" may be that the latter clearly signals a gain, while the former inherently implies a com pulsion to purchase two units to receive the price reduction.

Purchase characteristics of VDS and consumers' internal evaluation of VDS benefits
The previous studies on the factors influencing con sumers' perceived quality of the products (Chang, Wildt 1994;Dodds et al. 1991), have focused on the product's extrinsic cues (e.g. price, brand, and advertising). Brand image is one of the strongest signals of the unobservable qualities of a product Severi, Ling 2013) and when consumers use prices as a cue for qua lity, they infer higher quality with higher prices (Olson 1977). On the other hand, Bitta et al. (1981) proposed that a strong brand helps to control or stabilize the perception of quality of a product even when its price is discounted. Dodds et al. (1991) also found empirical support for the positive effect of brand on the perception of quality. In addition to certain productspecific information, a co gnitive relationship between consumers and products (i.e. image congruence) has been found to be a significant factor associated with consumer perception of a given product's quality (Graeff 1996;Pascale et al. 2000). For example, Graeff (1996) found that subjective product evaluation is a positive function of the degree of congruence between a consumer's selfimage and the image of the product or retail outlet. Pascale et al. (2000) also found that product evaluation was a positive function of selfimage congruen ce. Therefore, the more closely the consumer perceives the stereotype image of the product, the more likely they are to possess a favourable evaluative judgment of the product's quality. Bao et al. (2011) found that the store image is a diagnostic cue of store equity to consumers and allows them to infer the quality of merchandise.
Consumers tend to view themselves as responsible when they make a decision that results in a good outco me. This would suggest that smartconsumer feelings have important consequences for purchasing under SPs while those consumers who missed SPs will experience regret as a consequence. Berger and Heath (2007) found that brands allow consumers to perceive selfexpression value. On the other hand, Tykocinski and Pittman (2001) found that consumers who have missed an opportunity to purchase a product at a significantly reduced price are less likely to purchase the product at a later time due to promotional pricing. Hence, factors like brand, store, necessary pro duct, and deep sales promotion are expected to increase the perception of value in the minds of consumers and affect the selfexpression value.
Sometimes consumers need to travel frequently to the shops due to the nature of products in terms of fast con suming and necessity. On the other hand, if the products are nonperishable and storable, they can purchase more at one time. Therefore, the product category has an effect on consumers' perception of convenience towards purchase under VDS.
Proposition 1: There are positive relationships between the purchase characteristics of VDS and the consumers' evaluation of VDS benefits.

Consumer internal evaluation of VDS benefits and consumer intention to purchase products under VDS
A number of studies have examined empirically the effect of perceived quality on purchase intention (Chang, Wildt 1994;Dodds et al. 1991;Tsiotsou 2006). Some studies have found an indirect relationship between perceived quality and purchase intention, which is mediated by perceived value (Chang, Wildt 1994;Dodds et al. 1991) and satis faction (Tsiotsou 2006). In some studies, perceived quality has been found to have a positive direct effect on purchase intention (Parasuraman et al. 1996;SheauFen et al. 2012). In addition, Chandon et al. (2000) proposed perceived sa vings, perceived quality, perceived selfexpression value, and perceived convenience as the predictor of purchase intention.
Preposition 2: There are positive relationships between consumers' evaluation of VDS benefits and consumer in tention to purchase products under VDS.

Purchase characteristics of VDS and consumer intention to purchase products under VDS
Favourable brand image has a positive effect on purchase intention (Eze et al. 2012;Madahi et al. 2012). In addition, Wu et al. (2011) found store image affects purchase inten tion directly. Scheme characteristics, such as restrictions, can signal the value of a deal to the consumers (Raghubir et al. 2004), which leads to purchase intention. Chen et al. (1998) stated that message framing affects consumer inten tion to purchase under SPs. The subjective norm appears to have a significant effect on consumers' behavioural inten tion (Chang et al. 1996;Cheung et al. 1999;Chiou 2000).
Proposition 3: There are positive relationships between the purchase characteristics of VDS and consumer intention to purchase products under VDS.

Mediating effects of consumers internal evaluation of VDS benefits
Consumers with positive beliefs about promotional offers have tended to respond positively to the deal due to the benefits they obtain from purchasing. Therefore, it is expected that the offer appropriate purchase characte ristics of VDS will translate into better evaluations on VDS benefits, which lead to greater choice of promoted products. Bagozzi (1986) conceptualized that organisms mediate the relationship between stimulus and intention to purchase. There are many studies available in marketing Lii, Sy 2009) that support the mediating role of the organism.
Proposition 4: Consumer internal evaluation of VDS benefits mediates the relationship between purchase cha racteristics and consumer intention to purchase products under VDS.

Discussion
There are many conceptual research frameworks available on SPs, in general (Chandon el al. 2000;Raghubir et al. 2004), while only a limited number of conceptualization studies have been undertaken on volume discount. Even in the limited number of studies on volume discounts, the re searchers have not considered exhaustively all the potential purchase characteristics. Thus, a contribution of our work is to conceptualize a research framework to highlight the important purchase characteristics of consumers on VDS.
There are some conflicts in the findings of earlier re searches on SPs as well as SPs on volume discount. For instance, Sinha and Smith (2000) found that there is a po sitive relationship between the storable characteristics of products and consumer intention to purchase on volume discount, whereas Li et al. (2007) found the contrary. These contradictory findings suggest that the general conclu sions of prior research on important purchase characteris tics of volume discount need to be researched further. The potential reasons for these conflicts may be the difference in the selected product categories, such as storability and necessary difference of the products or the difference in selected stores, such as low/high equity brand or difference in promotion characteristics, such as depth of promotion and deal frequency. The factors that affect consumer in tention to purchase are interrelated, and, therefore, it is essential to consider all of them in one model and test them simultaneously. Our proposed model includes potential purchase characteristics together.

Managerial implications
The marketing research on promotional effectiveness is imperative at this juncture as SPs require a huge pro portion of marketing expenditure (Kotler, Keller 2009). Therefore, retailers and manufacturers should identify the most suitable SP strategies based on product and situation specific to have the greatest positive impact on consumer purchase decision to gain the targeted profit. Although retailers have been using VDS as one of the SP strategies for so long, questions relating to the situational factors that affect consumer intention to purchase products under VDS remain unanswerable. If situational factors, such as store type, brand type, and product categories affect consumer intention to purchase products under VDS then a key managerial implication is that retailers must know the expectations and needs of the consumers. In the challenging marketing situation of the present day, the consumers' expectations are very high, and, therefore, the retailers and manufacturers may seriously consider the brand image, store image, and the quality of products that are promoted under VDS. At the same time, due to heavy competition on the market, the retailers and ma nufacturers must study the frequency of SP under VDS to be offered for a product, the display of products of VDS (VDS banner, Price tag, packaging), the extra quantity of a product, business ethics, the duration of the sche me, and appropriate time of inception while keeping in mind the competitors for that product. The current study offers a conceptual model to test the appropriate product categories to be sold under VDS, which will aid retailers and manufacturers.
Although the retailers and manufactures have know ledge on SPs through VDS, the pricing of the products and relative quality as per the consumers' perception are conceptualized in the present study. This will give the re tailers and manufactures a better estimate of price and quality of the product to be promoted under VDS from the perspective of the consumers. The VDS has many benefits to the consumers, such as good deal to purchase a product, purchase before stocks finish, save time in shopping and reduction in number of shopping trips, provided the re tailers and manufacturers adopt the correct measures of business tactics.

Measurement issues
To empirically test our model, appropriate measures for the constructs in our framework must be developed and purified. Table 1 presents the various constructs used in our work and guidelines for their measurement. These measu res are suggested as potential starting points for detailed empirical work in this area.

Unit of analysis
Individuals whose age is above 14 years and have experien ced sales promotions under VDS during the last one year will be the unit of analysis. The restriction on age above 14 years is mainly due to the working age being from 15 years in most countries and needs to be modified based on the working rule of the country in which the experimental test of the proposed model will be conducted. Message framing refers to consumer guide to help them to have knowledge on price label of VDS products, its location of display in the stores and some form of instruction.
Attracted towards the display of amount of savings / percent of savings through volume discount on price label; attracted towards the display of old and new price after volume discount on price label / towards attractive label of products sold under VDS; VDS products display on "frontofthestore"; "until stock finishes" banner for VDS products. Gendall et al. (2006) Sub jec tive Norms The influence of friends, relatives, colleagues, and store employees accompanying the respondents while purchasing products under VDS.
Believe that, close associated / people around me / store employees will not object if I purchase products under VDS.

Self constructed
Per ceiv ed Sa ving The consumer perception of monetary savings during the purchase of VDS products.
Give importance to savings when purchased under VDS; when purchase a product under VDS, get a good deal; terms under VDS are really less expensive; with VDS, I am saving Money; the product under VDS seems to be a bargain; in VDS, the price of each item is less than what I expected it to be; in VDS, the price of each item is less than the average market price. Grewal et al. (1998);Parguel et al. (2007) Per ceiv ed Qua lity The consumers' judgment on promoted products under volume discount on the overall excellence or superiority of quality.
Give importance to quality when purchasing under VDS; satisfied with the quality of the product bought under VDS; the products which are sold under VDS are of high quality / very reliable / superior products Parasuraman et al. (1996); Grewal et al. (1998) Per ceiv ed SelfEx pres sion Value The consumers' selfperception of smartness may turn to disappointment or regret if the purchase of products under VDS yields loss.
If product purchased under VDS, have pleasure of having done a good deal; will be happy to have taken advantage of VDS offer; feel smart / feel lucky to purchase specially products under VDS; feel regret if miss out the VDS. Parguel et al. (2007); Raghubir et al. (2004) Per ceiv ed Con ve nience The consumers' perception of convenience to purchase products under VDS.
VDS makes shopping fast / easy; VDS reduces the number of trips to shop; feel more comfortable to purchase more in one purchase. Chandon et al. (2000); To et al. (2007) Intention to pur chase pro duct un der vo lume dis count sche me The consumers' intention on the probability of purchase decision under VDS.
Willingness to purchase under VDS is very high; the probability that purchase under VDS is very high; intend to purchase products under VDS when it is offered; expect to purchase products under VDS when it is offered; will recommend others to purchase special products under VDS. Grewal et al. (1998);Jayaraman et al. (2012)

Statistical data analysis
To fulfil the main objectives of the research, partial least squares (PLSSEM) is appropriate since it is suitable for identifying the key driver constructs and the structural model, which is complex (Hair et al. 2011). However, the PLSSEM is suggested for testing the proposed model as both the theoretical knowledge and substantive knowledge on volume discount is limited.

Conclusions
Volume discount is one of the attractive promotion strategy among Asian pacific consumers and is commonly prevalent in the market. In the present study, an attempt is made to investigate the situation in which volume discount warr ants for in the consumer points of view. In this context, a business model is proposed to study the determinants of volume discount in the form of product category, brand image, store image, message framing, scheme characteris tics, and subjective norms. Further, the ultimate benefits of volume discount through perceived savings, perceived quality, perceived selfexpression and perceived conveni ence on the predictor variables and the purchase intention on volume discounts are enlightened.