1. Introduction

The outbreak of COVID-19 in 2020 has changed consumers’ shopping behaviors and brought retailers challenges in many ways. Before the hit of the pandemic, traditional retailers relying on brick-and-mortar channel had already suffered intense competition from emerging online retailers. In 2019, over 9,300 retail stores in the U.S. were closed because they failed to change or embrace new retail strategies to meet new consumer needs, adapt digital innovation, and compete with online retailers [1]. In the meantime, share of e-commerce transactions by total U.S. retail transactions has grown from 4.2% in 2010 to 15.7% in 2020 [2]. Now, the pandemic is further forcing traditional retailers to adopt new retail strategies to stay competitive or just survive the retail disaster. Many scholars and market research companies predicted that, with the impact of the COVID-19 pandemic, online and digital formats would become the dominant shopping channels for consumers to obtain products and services and this trend would continue even in the era of post pandemic [3,4].

A majority of fashion retailers have severely suffered from the COVID-19 pandemic because they had to temporarily close their physical stores in compliance with the government order because fashion products were not categorized as "essential" goods and services like food, pharmacy products, etc. According to Business Insider, twenty-eight major retailers filed for bankruptcy or liquidation in 2020 due to the impact of COVID-19, among which, twelve were fashion companies owning famous brands such as J. Crew, Men’s Wearhouse, and Ann Taylor, or department stores such as Neiman Marcus and JC Penny [5]. Taylor [6] indicated there has been a prominent movement in the retail industry that retailers are shifting their investment from the physical store channel to digital channel and channel integration. For example, Zara’s parent company, Inditex, recently announced that they planned to close around 1,200 stores in 2020 and 2021, and believed that the revenue loss due to store closures would be offset by online sales and enhanced inventory management through effective channel integration [7].

Many marketers and researchers asserted that flexible marketing strategies, such as omnichannel retailing, can help retailers deal with the challenges they face during the pandemic and the uncertainties post the pandemic [4,6,8–10]. Prior to the pandemic, many retailers hesitated to implement omni-channel retailing services (e.g., purchase online pick-up in-store or subsidy pickup) because of the concern on potential decline in store traffic, but the pandemic has accelerated retailers’ adoption of these new shopping methods [6]. Beck and Rygl [11] defined omni-channel retailing as “the set of activities involved in selling merchandise or services through all widespread channels, whereby the customer can trigger full channel interaction and/or the retailer controls full channel integration” (p. 175). With the continuous advancement of digital and communication technologies, more retailers are becoming capable of providing additional channels besides physical store channel for consumers to explore such as online websites and mobile apps [12,13]. The core of omni-channel retailing is to provide consumers seamless and synchronized shopping experiences [12–16]. To reach the goal, a true channel integration is essential [16–19]. Therefore, omni-channel retailing is a business strategy offered by retailers for consumers to gain seamless shopping experiences, and consumers have the freedom to choose various shopping methods and channels at each stage of the shopping process from searching information to obtaining products [10].

Although the advantages of omni-channel retailing and the need of channel integration have been repeatedly emphasized in prior studies, there lacks research devoted to theoretical advancement and empirical investigation in how channel integration may affect consumers’ selection of omni-channel shopping methods [8,10,11]. In particular, our knowledge on the COVID-19 impact on consumer behavior towards omni-channel shopping is very limited [8]. Therefore, this study aimed to fill the gap in the literature by identifying the effects of channel integration in six aspects (i.e., promotion, product and price, transaction information, information access, order fulfillment, and customer service) on the U.S. consumers’ intentions to use three omni-channel shopping methods: buy online pick-up in-store (BOPI), buy online curbside pickup (BOCP), and buy in-store home delivery (BIHD). We proposed a mediation model to test the effects through consumer perceived values (i.e., hedonic value, utilitarian value), perceived risk, and perceived behavioral control. Moreover, this study explored the moderating effect of consumer perceived COVID-19 vulnerability on the relationships between consumers’ internal evaluations of channel integration and their shopping method selection intentions. The findings from this study provide the valuable insights to fashion retailers on the determinants of consumers’ selection of omni-channel shopping methods and the impact of the COVID-19 pandemic. This information may guide the corporate strategic investment in omni-channel retailing and contribute to maximizing the benefits of channel integration.

2. Theoretical Background and Hypotheses Development

2.1. Omni-channel Shopping Methods

Fashion retail industry mainly has three types of channels: store channel, online channel, and other non-store channel [12]. Online channel contains two subcategories: (1) traditional internet channel via computer or laptop, and (2) mobile channel via smartphone or tablet. Online channel also has a fast-growing subset, named social commerce, defined as e-commerce activities and transactions through social media sites [20]. Thus, retail online channels could be identified through two dimensions, hardware (e.g., computer, smartphone) and software (e.g., social media sites, brands’ or retailers’ websites). Other non-store channels include catalog, direct selling, and automated machines (e.g., vending machines). Large retailers often sell their products through various channels and allow consumers to flexibly choose the appropriate channel meeting their needs. Moreover, consumers can use multiple channels throughout their shopping process from information search, order placement, order pick-up, to post-purchase activities.

Bell [21] proposed an information and fulfillment matrix of four shopping modes: 1) traditional retail (obtain information and product offline), 2) shopping and delivery hybrid (obtain information online and pickup product offline), 3) online retail plus showrooms (obtain information offline and deliver product to home), and 4) pure-play e-commerce (obtain information online and deliver product to home). The first and the fourth kinds are single-channel shopping modes where product information and fulfillment happens within either offline or online channel, while the second and the third shopping modes are examples of integrated omni-channel retailing, which combines both online and offline channels.

In 2013, Macy’s launched an omni-channel program named “click-and-collect”, which integrates its digital wallet into both the Macy’s app and website [22]. No matter where and how consumers shops, either in Macy’s store or online, they have access to the consistent services or benefits Macy’s offers, such as the retailer’s loyalty program, special coupons, and the assorted payment methods [22]. This omni-channel strategy successfully meets the needs of Macy’s target consumers who have busy lifestyles and look for simple and convenient shopping methods. Researchers defined this “click and collect” service offered by many retailers (e.g., Walmart, Target, Kohl’s, Nordstrom, etc.) as buy-online-pickup-in-store (BOPS) or reserve-online-pickup-and-pay-in-store (ROPS) [23–25]. BOPS and ROPS belong to the same category in Bell’s [21] matrix, which is shopping and delivery hybrid, although BOPS is a more widely known shopping mode in the retail field. A recent study discovered that BOPS fulfillment operation could improve retail supply chain’s performance when it is offered under a centralized scenario (retailer and manufacturer work together to serve an integrated supply chain) [26].

Under the pandemic, retailers began offering many contactless shopping options to reduce the number of customers inside of stores and maintain social distance. Instead of having customers pick up their orders inside of stores, retailers slightly modified BOPS and began offering a similar omni-channel shopping method, called buy online pickup at curbside (BOPC) or just curbside pickup [27,28]. Shoppers could park their cars at designated curbside pickup area and shop assistants would walk outside to put their orders in the trunk or backseat. Business Insider recently highlighted sixteen retailers’ BOPS and BOPC options, which include famous fashion retailers such as Bloomingdale’s, JCPenney, L.L.Bean, Macy’s, Neiman Marcus, Nordstrom, and REI [29]. According to 2021 Omnichannel Report by Digital Commerce 360, at the beginning of 2021, 68.7% of U.S. retailers provided BOPS while 50.7% of retail chains provided BOPC [30].

Many Once-Online-Only retailers (e.g., Amazon, Warby Parker, Adore Me, Bonobos, and BaubleBar) opened physical stores because they realized that opening physical stores or showrooms can help increase sales across all channels and decrease the operational costs of shipping products that often do not meet customers’ expectations [31]. Temporary showrooms (“pop-up” shops or movable stores) are anticipated to have the similar advantages of boosting awareness and total demand [21]. An example for physical stores with minimum inventory but high level of customer service is “Nordstrom Local”. Those shops are identified as neighborhood service hubs with no dedicated inventory but offering a variety of services in small spaces with around 3,000 sq.ft [32]. When a physical store serves the role as a showroom, customers often choose the shopping mode of buy in-store home delivery (BIHD) [33], which is consistent with the shopping mode, reserve-online-pickup-and-pay-in-store (ROPS) that Bell [21] identified.

2.2. S-O-R Model

To investigate fashion consumers’ decision-making process for choosing omni-channel shopping methods, this study employed the Stimulus-Organism-Response (S-O-R) model by Mehrabiana and Russel [34]. This model successfully linked the three dimensions together: environmental incentive (stimulus), individuals’ internal states (organism), and consequent behavior (response) (see Figure 1). In other words, external factors or catalysts impact subjects’ actions through intermediaries of individuals’ judgements or intuitions. Thus, many marketing researchers were able to use this model to explore the impact of retailing environment on consumers’ actions through mediators of consumers’ internal evaluations such as consumer empowerment, perceived values, perceived risk, trust, etc. [35–38].

In the retail field, researchers often considered the stimulus as marketing-associated influences (e.g., sensory marketing and service characteristics) [37,39] or environmental attributes (e.g., store environment and website attributes) [40,41]. Previous studies have explored the effects of channel availability or channel integration as the stimuli on consumers’ cognitive and affective states [38,42,43]. For instance, by following the S-O-R model, researchers found that channel integration could significantly affect consumers’ empowerment, which in turn enhanced their trust and satisfaction as well as increased their patronage intention [35]. This study chose to investigate the influence of channel integration as the stimulus on consumer selection of omni-channel shopping methods as the response through the mediators of consumer internal evaluations as the organism.

Consumers’ internal states (organism) mainly include two aspects: pleasure and arousal [44]. Pleasure–displeasure is a condition of feeling that is either positive or negative, while arousal is a feeling condition with a certain degree of awakeness going from slumber to furious excitement. According to Bakker et al. [45], pleasure could be considered as affect while arousal could be considered as cognition. Prior studies demonstrated that cognitive and affective internal evaluations could significantly mediate the effect of environmental stimuli on consumers’ responses [45–49]. Researchers also found that consumer perceived value is a key organism factor bridging the environmental stimuli and consumers’ responses [36,50,51]. Consumer perceived value (both hedonic and utilitarian value) along with perceived risk and perceived behavioral control (PBC) were repeatedly reported as the significant factors influencing consumers’ adoption behaviors toward new technologies or new shopping channels [52–54].

Regarding the response, this study examined consumers’ selection intentions toward three omni-channel shopping methods: buy online pick-up in-store (BOPI), buy online curbside pickup (BOCP), and buy in-store home delivery (BIHD). In addition to these shopping methods, prior studies also discussed buy-online-return-in-store and reserve-online-pickup-in-store [55,56]. Current research focused on the stage of purchasing and receiving products during the shopping process. Since the returning and the reserving methods were not closely related to the interest of this study, they were excluded from the options of responses. Therefore, this study included and tested BOPI, BOCP, and BIHD as the three responses in the S-O-R model.

2.3. Stimulus: Channel Integration

Channel integration is one of the key success factors of omni-channel retailing implementation. For retailers being able to effectively apply the omni-channel strategy, they should integrate all channels seamlessly, and the integration needs to be implemented at all levels of logistics and marketing, and even internal business operations [57–60]. When online and offline channels are successfully integrated, businesses are able to maxmize the benefits of each channel, reduce cannibalization, and promote synergy, and as a result, businesses would reach better performance [61,62]. Channel integration is essential for retailers to provide the seamless shopping experience in the omni-channel environment [35,63,64]. According to Sousa and Voss [64], channel integration quality was assessed through two dimensions: channel–service configuration and integrated interactions. Channel–service configuration is defined as how good service quality is for each channel as well as the quality of the combined services across different channels [64]. In other words, channel–service configuration is the scope of channel choice and flexibility of the combinations of different services and channels. Integrated interactions involve the consistency and standardization of both content (e.g., response to a question or information across different channels) and process (e.g., process features such as service’s experience, appearance, waiting times, and employee power levels).

Instead of identifying channel integration from the perspective of service quality like Sousa and Voss did [64], more recently, Oh, Teo and Sambamurthy [62] defined channel integration by analyzing all possible retail activities in three regular phases of the buying procedure: pre-purchase, purchase, and post-purchase. They proposed six dimensions of retail channel integration (i.e., integrated promotion, integrated transaction information management, integrated product and pricing information management, integrated information access, integrated order fulfillment, and integrated customer service). After testing the impact of these dimensions on multichannel retailers’ performance, Oh et al. [62] discovered that channel integration enabled by information technologies improves firms’ competencies in delivering both existing resources and future innovative contributions, which in turn enhances the overall performance of the firms. Lately, Zhang et al. [35] refined the six channel integration dimensions to accommodate the emerging omni-channel retail trend and from the perspective of consumers.

In line with prior researchers’ definitions and measurement of channel integration, this study considered channel integration as the extent to which a retailer synchronizes all available channels and all levels of the organization to boost synergy for the business and offer consumers seamless and flexible shopping experiences. The dimensions of retail channel integration focused in this study are: (1) integrated promotion (IP), (2) integrated product and price (IPP), (3) integrated transaction information (ITI), (4) integrated information access (IIA), (5) integrated order fulfillment (IOF), and (6) integrated customer service (ICS). Table 1 summarizes the definitions of the six dimensions as below. These definitions were used to guide the development of the constructs of the six channel integration dimensions.

Table 1. Channel integration dimensions in the omni-channel environment.

2.4. Organism: Consumer Perceived Value

Perceived value evolves from the means-end theory, which demonstrates that values consumers perceive are the ends from the products’ attributes representing the means [65]. Prior studies discovered that perceived value was the key for understanding consumer behavior in the marketplace [66,67]. Thaler [68] defined value as a trade-off which is the net benefits of the difference between consumers’ perceived gains and losses. Zeithaml [69] further developed the meaning of perceived value as “the consumer's overall assessment of the utility of a product based on perceptions of what is received and what is given” (p.14). As stated by Babin et al. [70], perceived shopping value mainly contains two dimensions: hedonic and utilitarian values. When consumers make purchase decisions, they take all the decision factors (both hedonic and utilitarian values) into consideration and mentally calculate if it is worth the price and cost of the deal [71]. Current research examined the impact of both hedonic and utilitarian values as the mediators connecting channel integration and consumers’ shopping method selection intentions.

Prior studies discovered that consumers chose to use multi-channel or omni-channel integration while shopping because they perceived both hedonic and utilitarian values of this type of shopping method [72–75]. Pragmatic consumers liked to use multi-channel integration because they perceived utilitarian values (e.g., money, time, and effort saving) of this shopping process while shopping beginners are more likely to shop for the hedonic reasons (e.g., enjoyment and pleasure) than multi-channel shopping experts [72]. For example, researchers found significant relationships between online promotion and both functional and emotional value among e-commerce shoppers in China [51]. Price promotions often stimulate consumers’ shopping intentions because consumers often perceive functional value in a deal for its cheaper price [76]. Moreover, consumers also get excited and pleasant (perceive hedonic value) when seeing and noticing a favorite product is on sale or promotion. When promotion information is provided in an omni-channel environment, the effect might be even stronger because integrated channels could offer consumers more convenient and fun shopping experiences [73,77,78].

Prior findings showed that cross-channel integration dimensions (e.g., information consistency, freedom of channel selection, strong customer services, channel reciprocity) were positively related to consumers’ hedonic and utilitarian shopping purposes [75]. These dimensions are similar to the channel integration dimensions examined in this study. According to Wu and Chang [77], in a multi-channel retail environment, consumers generate more trust toward the businesses who provide coherent information and shopping process across all the channels. With higher trust, consumers would probably generate more favorable assessments (e.g., monetary savings, convenience, and hedonic value) toward products, information and services [77]. Thus, coherent information (i.e., IP, IPP, ITI) and consistent shopping process (i.e., IIA, IOF, ICS) across different channels may induce consumers to perceive higher functional and hedonic values [79]. Therefore, hypotheses 1a–f and 2a–f were proposed as follows.

Hypothesis 1. (a) Integrated promotion (IP), (b) integrated product and price (IPP), (c) integrated transaction information (ITI), (d) integrated information access (IIA), (e) integrated order fulfillment (IOF), and (f) integrated customer service (ICS) have positive impact on consumer-perceived hedonic value in the omni-channel retail shopping context.

Hypothesis 2. (a) Integrated promotion (IP), (b) integrated product and price (IPP), (c) integrated transaction information (ITI), (d) integrated information access (IIA), (e) integrated order fulfillment (IOF), and (f) integrated customer service (ICS) have positive impact on consumer-perceived utilitarian value in the omni-channel retail shopping context.

2.5. Organism: Perceived Risk and Perceived Behavioral Control

In addition to consumer perceived values, consumers may generate other evaluations (perceived risk and perceived behavioral control) when utilizing integrated channels in the omni-channel retail setting. Morgan and Hunt’s commitment–trust theory demonstrated the importance of trust in business relationships and the negative relationship between trust and uncertainty [80]. Trust could decrease consumers’ perceived risks in the shopping procedure, such as transaction risks [81]. Perceived risk (PR) refers to the level of uncertainty consumers perceive regarding using omni-channel shopping method for purchasing apparel products [82,83]. Perceived behavioral control (PBC) is a key concept in the theory of planned behavior (TPB), a popular ethological theory extended from the theory of reasoned action [84]. TPB is often utilized as the theoretical foundation to explain technology adoption [85]. According to Chen [86], PBC includes two aspects: perceived control and perceived difficulty. In this study, PBC is identified as the level of reorganized simplicity or difficulty of executing the action, using omni-channel shopping methods [87].

Prior studies showed that channel integration in the retail setting, especially, integrated product and price cross channels could help reduce the risk consumers perceived when purchasing products online [77,83]. Other studies also demonstrated the impact of channel synergy on reduction of perceived risk of online channel [79,83,88]. Xu and Jackson [83] investigated three important features of successful omni-channel retailers (i.e., channel transparency, channel convenience, and channel uniformity, and discovered that these features were negatively related to consumers’ perceived risk. In a recent study, IP, IPP, and ITI were determined as moderators impacting the relationships between online channel media richness (OCMR), and two risk-related variables, information privacy concern and perceived deception toward website channel [79]. The results showed that all three moderators (IP, IPP, and ITI) could improve the negative relationships between OCMR and consumers’ concerns toward an online channel because adding an offline channel could mitigate some of the concerns consumers hold toward transaction and privacy risks in a pure online setting.

Although some aspects of channel integration (e.g., integrated promotion, integrated product and price) seem to be able to reduce uncertainties in the online channel, some consumers still have concerns on their personal information security in the omni-channel retail environment when big data and other information integration technologies are used. Piotrowicz and Cuthbertson [89] stated that the balance between personalization and privacy was a key issue in the omni-channel retail environment, especially when consumers’ information was overused for marketing purposes. Furthermore, many researchers asserted that the application of big data and predictive systems in the retail setting would cause consumer backlash because many consumers had concerns for personal data breaches [89–92]. According to Bradlow et al. [90], if retailers practice some information protection techniques (e.g., opt-in policy), consumers would have less concerns for the information privacy issue and generate more favor toward the information services provided by omni-channel retailers. Since the current study did not limit respondents’ omni-channel shopping experiences to those retailers engaged in information protection practices, the respondents might still hold unfavorable attitude toward the two information-related integration involved in consumers’ personal information: integrated transaction information (ITI) and integrated information access (IIA). Therefore, this study proposed four negative relationships (3a, 3b, 3e, and 3f), and two positive relationships (3c and 3d) with perceived risk as follows.

Hypothesis 3 Integrated promotion (IP) (a), Integrated product and price (IPP) (b), Integrated order fulfillment (IOF) (e) and Integrated customer service (ICS) (f) negatively affect perceived risk in the omni-channel retail context while Integrated transaction information (ITI) (c) and Integrated information access (IIA) (d) positively affect perceived risk in the omni-channel retail context.

In addition to perceived risk, researchers also demonstrated the connections between channel integration and perceived behavioral control (PBC). Xu et al [83] revealed that the three omni-channel characteristics, namely, channel transparency, channel convenience, and channel uniformity, had significantly positive influence on PBC of using omni-channel shopping methods. Some researchers explored the impact of channel integration on consumer empowerment, a similar concept to PBC, and found the significant relationship [38,42]. The relationship between channel integration and PBC was justified as that when all the information and services were well integrated across different channels, consumers would become more confident and certain about their capability of purchasing products whenever, wherever, and however when using omni-channel services [38,42]. Therefore, we proposed that when the six dimensions of channel integration achieved a higher level, consumers would perceive higher behavioral control of using the omni-channel shopping methods. The hypotheses 4a–f were proposed below.

Hypothesis 4. (a) Integrated promotion (IP), (b) integrated product and price (IPP), (c) integrated transaction information (ITI), (d) integrated information access (IIA), (e) integrated order fulfillment (IOF), and (f) integrated customer service (ICS) have positive impact on perceived behavioral control (PBC) in the omni-channel retail context.

2.6. Behavioral Responses and Moderating Effect of Perceived COVID-19 Vulnerability

This study examined U.S. consumers’ selection intentions of the three popular omni-channel shopping methods (i.e., BOPI, BOCP, and BIHD), and proposed that the four mediators (i.e., PHV, PUV, PR, and PBC) would directly influence the intentions of choosing the omni-channel shopping methods. Prior studies showed the connections between these mediators and consumers’ behavioral responses, such as purchase intention, repatronage intention, channel selection intention, and channel switching intention [23,74,77,78,83,93]. Kim et al. [16] found that hedonic motivation positively impacted consumers’ behavioral intentions toward using BOPI. Other studies revealed that utilitarian value (e.g., save time, money, and effort) was the primary determinant of consumer selection BOPI method [94,95].

According to Lee et al. [94], PBC positively influenced consumers’ intentions toward using BOPI because when an order was placed online for in-store pickup, consumers could pick up the order within a short time and check the quality of the product in person. This process makes consumers feel that they have control over the whole shopping process and they are able to reach their goals [94]. Moreover, BOPI service may help reduce the risks of getting defective or wrong products since consumers could reject the products in the store, save shipping cost and waiting time, and receive immediate gratification [87]. All the effects explained above should have the same effects on BOCP because BOPI and BOCP are two similar services. The only difference is, when using BOCP, consumers could wait in their car for their order instead of walking inside of the store. BOCP has become a popular shopping method during the pandemic for the safety consideration.

Rather than purchasing product online and picking up order offline like BOPI and BOCP, consumers can purchase products in store and receive their orders through shipment when using the BIHD service. Similar to BOPI and BOCP, BIHD also allows customers to see and touch products in person, which may reduce their concerns and uncertainties about products’ fit and performance [96,97]. Under this circumstance, customers can not only receive joy and happiness of browsing and trying on products in the physical store channel, but also receive the convenience of the shipping service if the products they purchase are too many or large to carry with them. Moreover, air travelers may also avoid extra charges for their overweight luggage by having the retailers ship the orders directly to home. Thus, BIHD service can also provide consumers hedonic and utilitarian values, as well as reduce perceived risks. If they see an omni-channel shopping method as easy or less difficult to practice, they will be more likely to use the method for shopping fashion products. Therefore, we proposed that perceived hedonic and utilitarian values and perceived behavioral control could positively affect consumers’ selection intentions toward the three omni-channel shopping methods (i.e., BOPI, BOCP, and BIHD) while perceived risk could negatively affect consumers’ shopping method selection. Hypotheses 5a–d, 6a–d, and 7a–d were proposed as follows.

Hypothesis 5. (a) Perceived hedonic value (PHV), (b) perceived utilitarian value (PUV), (c) perceived risk (PR), and (d) perceived behavioral control (PBC) significantly affect the consumers’ intention to use buy online pick-up in-store (BOPI).

Hypothesis 6. (a) Perceived hedonic value (PHV), (b) perceived utilitarian value (PUV), (c) perceived risk (PR), and (d) perceived behavioral control (PBC) significantly affect the consumers’ intention to use buy online curbside pickup (BOCP).

Hypothesis 7. (a) Perceived hedonic value (PHV), (b) perceived utilitarian value (PUV), (c) perceived risk (PR), and (d) perceived behavioral control (PBC) significantly affect the consumers’ intention to use buy in-store home delivery (BIHD).

Consumer behaviors changed under different stages of the pandemic, across different countries and areas, and under different governmental policies. Individual differences influenced consumers’ channel selections [98]. In a recent study, researchers investigated apparel consumers’ channel shifting intentions during the COVID-19 pandemic and discovered that perceived vulnerability (PV) affected consumers’ attitude toward shifting to online channel from physical channel [53]. In other words, when consumers held stronger belief toward that if they got sick from COVID-19, the situation would be serious, they would be more likely to switch to online channel to purchase fashion products. Perceived vulnerability is the key concept in the protection motivation theory for measuring threat appraisals (the degree of risk of perilous actions) [99]. Moon et al. [98] revealed that perceived vulnerability and offline-channel use intention were negatively correlated. BOPI and BOCP services could help reduce the searching and browsing time consumers might spend in physical stores or even skip the offline channel (walk-ins) to receive orders. However, BIHD service requires consumers to shop inside of stores, which might seem to be riskier under COVID-19. Thus, we proposed that PV might enhance the relationships between the four mediators (i.e., PHV, PUV, PR, and PBC) and the selection intentions toward BOPI and BOCP, but weaken the relationships between the four mediators and the intention to use BIHD. Therefore, the hypotheses 5e–g, 6e–g, and 7e–g were proposed as follows.

Hypothesis 5. Under the omni-channel retail context, the higher the perceived COVID-19 vulnerability, the greater the impact of (e) perceived hedonic value (PHV), (f) perceived utilitarian value (PUV), (g) perceived risk (PR), and (h) perceived behavioral control (PBC) on the intentions to use buy online pick-up in-store (BOPI).

Hypothesis 6. Under the omni-channel retail context, the higher the perceived COVID-19 vulnerability, the greater the impact of (e) perceived hedonic value (PHV), (f) perceived utilitarian value (PUV), (g) perceived risk (PR), and (h) perceived behavioral control (PBC) on the intentions to use buy online curbside pickup (BOCP).

Hypothesis 7. Under the omni-channel retail context, the higher the perceived COVID-19 vulnerability, the weaker the impact of (e) perceived hedonic value (PHV), (f) perceived utilitarian value (PUV), (g) perceived risk (PR), and (h) perceived behavioral control (PBC) on the intentions to use buy in-store home delivery (BIHD).

3. Proposed Research Model and Developed Survey Instrument

According to the literature review above, an integrative S-O-R model for fashion omni-channel retailing covering all the proposed relationships (48 hypotheses) is delineated in Figure 1. Integrated promotion (IP), integrated product and price (IPP), integrated transaction information (ITI), integrated information access (IIA), integrated order fulfillment (IOF), and integrated customer service (ICS) may affect U.S. consumers’ perceived value (perceived hedonic value (PHV) and perceived utilitarian value (PUV)), perceived risk (PR), and perceived behavioral control (PBC) toward apparel omni-channel retailing. Consequently, the U.S. consumer’s perceived value, perceived risk, and perceived behavioral control may affect their omni-channel shopping method selection including buy online pick-up in-store (BOPI), buy online curbside pickup (BOCP), and buy in-store home delivery (BIHD). Perceived COVID-19 vulnerability (PV) may moderate the correlations between perceived value, perceived risk, and perceived behavioral control and U.S. consumers’ shopping method selection. The demographic variables including age, gender, income level, and education level were treated as control factors.

Figure 1. Proposed research model.

The six dimensions of channel integration (i.e., IP, IPP, ITI, IIA, IOF, and ICS) were adapted from Oh et al. [62] and Zhang et al [42]. Perceived hedonic value (PHV) and perceived utilitarian value (PUV) were adapted from Babin et al. [70] and Picot-Coupey et al. [100]. The scales for perceived risk (PR) and perceived behavioral control (PBC) were adapted from Xu et al. [83]. The scales for the selection intentions of the three omni-channel shopping methods, buy online pick-up in-store (BOPI), buy online curbside pickup (BOCP), and buy in-store home delivery (BIHD), were also adapted from Xu et al. [83]. The scale for the moderator, perceived COVID-19 vulnerability (PV), was adapted from Youn et al. [53]. For the selection intentions of the three omni-channel shopping methods, the authors applied a seven-point Likert scale (1 = extremely unlikely, 2 = moderately unlikely, 3 = slightly unlikely, 4 = neither likely nor unlikely, 5 = slightly likely, 6 = moderately likely, and 7 = extremely likely). For the rest of the variables, a seven-point Likert scale (1 = strongly disagree, 2 = disagree, 3 = somewhat disagree, 4 = neither agree nor disagree, 5  = somewhat agree, 6 = agree, and 7 = strongly agree) was applied.

4. Methodology