Home Meal Replacement (Convenience Food) Consumption Behavior of Single-Member Households in Vietnam by Food Consumption Value

: The home meal replacement (HMR) market in Vietnam is expected to grow due to economic growth and the associated reduction in household size resulting from this. This study sets the development direction of HMR products and establishes product marketing strategies in the Vietnamese market through market segmentation of single-member households. Our survey targeted single-member households with regular HMR experience. Food-consumption value is used to identify market segmentation and differences in purchase behavior, such as preferences for a speciﬁc HMR type, the importance and performance of HMR selection attributes, and the demand for product development. The single-member households in Vietnam are segmented by purchasing simplicity and convenience, considering multiple options, and purchasing family safety. The family-oriented culture of Vietnam inﬂuences the evaluation of family safety, while the situational value reﬂects climate features. Meanwhile, taste, expiration date, sanitation, and nutrients are found to be key attributes. This study targets the impact of these effects on single-member households, given that household size is rapidly decreasing in Vietnam and there is a lack of research on the Vietnamese HMR market. Additionally, it highlights the inﬂuence of Vietnam’s culture and climate characteristics by utilizing segmented markets, which can also be utilized to develop market-tailored HMR products and to derive appropriate marketing strategies.


Introduction
There has been a widespread tendency to postpone marriage and enjoy the individual self-realization and freedom of a single lifestyle across the world [1]. As a result of this tendency, the size of households worldwide is shrinking. In particular, one-third of the households in Europe and North America are single-member households [2]. In Vietnam, this phenomenon of shrinking household size and an increase in single-member households also exists [3]. In 1985, Vietnamese families with four or five members accounted for approximately half the total number of households, while single-member households were the smallest group, at 4.3%. By 2009, the number of households with two or three members (36.3%) and single-member households (7.3%) had increased [3]. According to the 2019 Vietnam population and housing census [4], the number of single-person households has continued to increase to 10.4%, and the number of households with two to three members has risen to 38.4%. This tendency is expected to accelerate along with economic development [5] and urbanization [6].
As part of this trend, further changes in food-consumption behavior are expected in Vietnam. Increases in individual disposable income, urbanization, and shrinking household size driven by rapid national economic growth fuel this trend. In particular, single-member households are regarded as the new main consumers in this market [7][8][9]. Because they have more time and money than multi-member households, their influence in the consumer market has expanded, and the term "solo economy" has now appeared to describe this trend [10]. Several studies have revealed that single-member households have different characteristics from multi-member households. Single-member households are thought to be successful people, and they are considered to be sophisticated consumers and a group that values independence in their lives [11]. Moreover, single-member households tend to pursue convenience in food consumption and preparation to a greater extent than multimember households [11]. As such, due to the distinctive characteristics of single-member households compared to multi-member households, various industries are developing products and services for them.
In Korea, where the number of single-member households has also rapidly increased, the number of small houses, small furniture, and small home appliances for single-member households has grown. In the food market, small packaging and small-capacity products are expanding [8]. Social, economic, cultural, and demographic characteristics according to household size are very important for understanding modern life. For this reason, it is necessary to consider household size in the study of food-consumption behavior [12]. As the size of single-member households in Vietnam is expected to continuously increase, it is also essential to understand their food-consumption behavior and the factors affecting this.
Food-consumption value (FCV) is a main determinant of food-consumption behavior. Value is a key factor in understanding social phenomena and, even when we are not conscious of the value, our behavior is influenced by individual values [13]. Thus, to understand human behavior, it is necessary to understand the values of both individuals and groups. Values also influence behaviors related to dietary life, such as food selection and consumption. Individuals' food choices are based on their life experiences and, accordingly, influence their food selection decisions [14]. Grunert [14] defines the factors on which individuals place weight in terms of food consumption as food-selection values; those typically encompass taste, health, ease of use, and price. Dagevos and Ophem [15] argue the need to focus on consumers in constructing FCV and suggest four values: product, process, place, and emotional value. FCV changes due to marriage, children, and other lifecycle changes [16], but it may also change under the influence of rapid social changes and the influx of other cultures.
These rapid social and economic changes in terms of urbanization and shrinking household size have also contributed to the growth of the home meal replacement (HMR) market [17][18][19][20], with the Vietnamese HMR market especially being expected to grow further. In Vietnam's HMR-related market, the growth of the convenience store market, which is the main purchase channel for HMR, and the contraction of the traditional market, are in line with increased income levels due to urbanization and the emergence of young consumers [21].
Vietnam has a background in HMR market growth and has been selected as a country where Southeast Asian companies locate if they want to further advance as part of the growth of the global HMR market [22]. However, although the HMR market in Vietnam is expected to grow significantly, studies of its likely composition and size are limited. In particular, there are practically no studies on the food-consumption value of HMR in Vietnam and relevant purchase behaviors, including the actions of single-member households [23]. For example, the relationships between personal value, marketing attitude, trust in nutrients, and convenience-food-store use [24]; and the impact on the attitude and purchase intention of Korean ginseng products [25] should be analyzed.
Vietnam society has a complex mix of values due to its diverse ethnic composition and colonial history, which are expected to affect FCV and behavior. When targeting overseas markets, it is essential to define product concepts and prepare marketing strategies that reflect the product needs of local people, based on product safety, legality, and fairness. Furthermore, understanding the food-consumption-related values that consumers have can play an important role in setting marketing directions and devising strategies for the food industry, thus providing an opportunity to secure a competitive advantage in the market [15].

Home Meal Replacement and Consumption Behavior
HMR is a meal solution that uses products produced outside the home to be consumed at home as a major food source for busy people [26]. A meal solution is used when an individual cannot cook or does not want to cook. The meal solution consumed at home is classified as HMR and, in contrast to meals provided in hotels, restaurants, and catering institutions and facilities, consumers can have it at home by directly purchasing food or using delivery services. As diverse HMR products have been developed and have become more readily available in the market, the scope of HMR has been expanding. In a broad sense, HMR can be classified according to retail market standards depending on the cooking and preparation processes used after purchasing the products. There are four types: ready-to-eat (RTE), ready-to-heat (RTH), ready-to-consume (RTC), and ready-to-prepare (RTP) [27].
Household size, household characteristics, consumption level, and age influence HMR consumption behavior [28][29][30][31]. Hwang and Choe [28] analyzed the differences in HMR consumption behavior according to income level and proposed an expanded study on various factors that affect HMR consumption behavior by income level. Daniels and Glorieux [29] analyzed convenience-food-consumption behavior according to the life cycle and social groupings of Belgians and found that 30% of their food expenses are spent on convenience food, and there was a difference in convenience-food-consumption behavior according to household composition. In a study on the differences between conveniencebased-food purchase pattern classifications and convenience-food purchase behavior, the main factors influencing convenience pattern adherence were household size and the presence of children [30]. Cha and Seo [31] found that there are age-related differences in HMR brand image and trust.
As such, as studies on HMR are being actively conducted and the main research topics being subdivided, several studies have been conducted targeting Southeast Asian countries, where companies want to enter due to the high marketability of these products.
Lovell [32] revealed that taste is a crucial factor in a study of Thai repurchase behavior related to frozen convenience food, and their influencing factors, namely ease of use, price, brand, and preparation time, also contributed to purchase behavior. Osman et al. [33] studied convenience food consumption and influencing factors for employees in Malaysia and found that the time factor affects convenience-food consumption. Baskaran et al. [34] researched the intrinsic and extrinsic factors that affect HMR purchase intentions for general consumers in Malaysia. According to the results of this study, the need for research on various factors affecting purchase intention, such as nutrition, price, safety, packaging, brand image, and convenience, should be emphasized.
Kim et al. [35] targeted Singaporean consumers and investigated the importance of purchase attributes and the preference of product attributes for ginseng-chicken-soup HMR products. The importance of packaging, chicken shape, glutinous rice inclusion, flavor, and ginseng were found as the attributes that influence the purchase of chicken soup as HMR. Mandelkar [36] studied the factors influencing the intention to purchase HMR products for consumers in Bangkok, Thailand, and found that ease of use was the most essential factor. Meanwhile, Thienhirun and Chung [37] targeted Thai and Japanese consumers' perceptions of and preference for HMR products. While consumers in both countries had negative perceptions of the taste and freshness of HMR products, there was a difference between them: Thai consumers prefer a localized taste, whereas Japanese consumers prefer an authentic taste.
As mentioned above, there have been several HMR-related studies targeting Southeast Asia, but they have been limited to countries such as Thailand and Malaysia. Moreover, HMR studies that reflect the characteristics of single-member households are very limited, so it is necessary to conduct more research targeting Southeast Asian countries, including Vietnam, which has the driving force to increase its retail market for these products.

Food-Consumption Value
Value is an important factor in understanding various social-psychological phenomena [14]. According to Schwartz [38], value is inseparable from belief and is associated with desirable goals that motivate behavior. In addition, in contrast to norms and attitudes, values have influence, without limiting specific actions and situations, and serve as criteria for selection and evaluation. Humans show behaviors corresponding to their values, even when they are not conscious of these values [39], and these should be understood first to comprehend human behavior.
Various factors influence food selection and consumption. According to Connors et al. [16], in the process of food selection, humans construct individual food systems based on their experience and make food-selection decisions accordingly. Furthermore, factors such as taste, health, ease of use, and price, which are crucial in the process of food selection, are defined as food-selection value. Values are an important factor influencing food selection and can be used as a tool to predict eating behavior [14]. They also play a key role in establishing food-related public policies, and in the food industry, they are considered essential for designing marketing strategies and securing competitiveness [15]. However, existing food-related values have been structured around the nutritional value of food and cost/price-related values. Dagevos and Ophem [15] argue for the need to expand product-oriented values to reorganize them to center on the consumer's viewpoint based on four values: product, process, place, and emotional value. These values include elements from production to consumption, practical aspects of products, and emotional elements.
According to Connors et al. [16], the values of consumers change based on factors such as marriage, birth of children, and diseases that occur during the lifecycle. When selecting food, their values collide. In a situation of conflict of values, to enable the smooth functioning of the food system that satisfies individual values, consumers go through the processes of classifying food and consumption situations, prioritizing values in line with the food-consumption situation, and creating a balance between values. Accordingly, to understand consumers and satisfy their needs, it is necessary for the food industry to first identify the characteristics of target consumer groups by lifecycle, as well as the values of each group, and pay attention to the changes in group characteristics that take place as a result of various factors.
As for FCV-related studies, the studies on HMR products are rather limited. Lee and Hong found that emotional value and conditional value among consumption values influence attitude, satisfaction, and purchase intentions toward refrigerated HMR products [40]. Kang studied the relationship between consumption value and convenience-store lunch-box repurchase intention and found that functional consumption value, which is the perceived utility of consumers for practical functions related to product quality, function, price, and service, influences convenience store lunch box repurchase intentions [41]. That study pointed out the need for quality improvement through the results. These studies indicated that FCVs, such as emotional, situational, and functional values, can affect our attitudes toward consumption behavior and purchase intentions.
There is a study targeting the Southeast Asian market, including Vietnam, about consumer attitudes toward Korean ginseng products and its effects on purchase intentions [25]. However, there are only limited studies on the consumption behavior and value of HMR products. FCV is a major influencing factor on food-consumption behavior and a tool for predicting eating behavior [15]. Since understanding the characteristics of target markets through food-consumption values can be used for product development and commercialization strategies that match these values, its importance is very high.

Research Subjects
This study targeted single-member-household consumers residing in Vietnam. There are diverse terms related to single-member households: one-person households and solo living focusing on single-living and single and singlehood focusing on marital status [42][43][44][45][46][47]. Factors such as marital status and lifestyle were taken into account when selecting a single-member household consumers, and it also included those without a spouse due to divorce or bereavement. Accordingly, this study defines a single-member household as "a household that does not currently have a spouse legally and practically and is living alone after separation from a household". The age of study subjects is limited to those aged 19 to 39 years old, in consideration of the Vietnamese average age (30.9 years old; Worldometers 2019). Moreover, since the ratio of single-member households in Vietnam is not high [3,4], the residence of the subjects of the study was set for the whole of Vietnam. In addition, to collect data that coincide with the purpose of this study, we targeted consumers who had HMR experience and used HMR products frequently.

Research Methods and Period
As the number of Vietnamese single-member households in the population is not sufficient, a convenience sampling method was used. In this approach, age and gender were equally allocated to minimize the bias of responses according to their influence. The questionnaire was implemented by Macromill Southeast Asia Vietnam, a local survey agency in Vietnam that has Vietnamese single-member household consumer panels, and an online survey was conducted from 22 October to 10 November 2019 to recruit survey respondents from all over Vietnam. The questionnaire was written in Vietnamese, and the concept, types, and examples of HMR were presented to enhance understanding of the survey contents. An email with an online survey link was sent to the panelists who met the survey criteria. The survey subjects accessed the online survey system and participated in a self-administered questionnaire. Before answering the survey questions in earnest, only those who met the survey criteria were allowed to participate in the questionnaire by asking questions about their HMR experience and age. A total of 250 questionnaires were obtained for statistical analysis.

Organization of the Questionnaire and Statistical Processing
The questionnaire was composed of questions on FCV, preference per HMR product type, importance of HMR selection attributes, demand for HMR development, and demographic and general details, based on previous research. The food-consumption-value items were divided into product, price, health, safety, time, family, convenience, packaging, and situational value. In food consumption, product, price, health, and safety are considered essential characteristics [47,48]. Accordingly, in this study, food-consumption values were also constructed to be centered on product, price, health, and safety. The product value questions covered the taste, variety, and quantity of the product, and the price value questions focused on the economic situation and cost-effectiveness of individuals when consuming food [25,47,49,50]. In addition, health value was centered on concerns about calories, fat, sugar, and sodium in food consumption [50], and safety value was centered on concerns about additives and other artificial substances, bacteria and viruses, and food poisoning [47][48][49]. To measure the food-consumption value related to HMR, time and convenience, such as meal preparation and cleaning, should be considered in consideration of the modern lifestyle. Reflecting this, convenience values included convenience of eating time and place, as well as meal preparation and cleaning [25,[48][49][50].
Time value is similar to convenience, but it is focused on time saving and utilization [49]. Various types of packaging are used for HMR, and packaging can also function as an influencing factor on HMR consumption [51][52][53]. The packaging-value items, including the characteristics and design of materials, were constructed on this basis [25,47]. Similar to East Asian countries, Vietnam is a country that places great importance on family, due to its historical background as a Confucian country [54,55]. For the Vietnamese, the family is central to their social life, and filial piety to their parents and duty to their siblings are essential [56]. Accordingly, family ties are also very strong. Scandinavian countries and Eastern European countries show weak ties; the US, Canada, and UK show moderate ties; and Vietnam, the Philippines, and Indonesia show very strong familial ties [57]. The characteristic of Vietnam that places importance on the family is maintained despite changes in the political and social system [54]. Consequently, the family value was constructed while considering the possibility that the influence of the family may exist in food consumption [53][54][55][58][59][60] and in situational-value items related to Vietnam's climatic features [61,62].
Finally, to measure the preference per HMR product type, this was classified into 4 based on previous studies [27]. Selection attributes are tangible and intangible characteristics of a product and are a major factor influencing the time when consumers consume a product [63,64]. As for the selection attributes, various items, such as product characteristics, including taste, quantity, texture, ingredients, and nutritional components; brand; hygiene and safety; convenience-related items; and packaging and design items, have been dealt with in previous studies [65][66][67][68][69][70]. Nineteen suitable items were selected. The details of the organization of the questionnaire are presented in Table 1. HMR consumption behavior Preference of HMR product, importance and performance of HMR selection attributes, and demand for HMR development [27,40,[65][66][67][68][69][70] A 7-point Likert scale analysis was used for FCV, preference per HMR product type, importance of HMR selection attributes, and demand for HMR development. All statistical analyses in this study were performed by using SPSS Statistics (Version 23.0). Frequency analysis was used to analyze the demographic and general characteristics of the study participants. FCV was verified for validity and reliability via factor and reliability analysis, and K-means cluster analysis was performed for grouping factors. Cross-analysis and the analysis of variance (ANOVA) were performed to examine the differences in consumption behavior by FCV cluster; if a significant difference was found as a result of ANOVA, a post hoc analysis was performed, using Scheffe's test.

Categorization of Food-Consumption Value
The results of factor and reliability analyses for the categorization of FCV are presented in Table 3. The varimax rotation method was used, and the number of factors was based on an eigenvalue of ≥1.0. As a result of applying a factor loading of 0.5 or higher to secure validity, 10 items with a lower factor loading were excluded from the total of 46. Eight factors were finally derived, with a total of 36 items, and the total variance explanatory power was 70.68%. Cronbach's α values for all factors were 0.7 or above, indicating high reliability (Appendix A Table A1). Note: *** p < 0.001. A seven-point scale was used (1 = strongly disagree, and 7 = strongly agree). a,b,c Differences in the same row are significantly different when Scheffe's test is used.
The cluster-analysis results for segmenting the market based on the FCV are shown in Table 4. A cluster analysis was performed by setting eight FCV factor scores obtained from the factor analysis as a reference variable. As a result of using the K-means clustering method, it was desirable to classify them into three groups; the characteristics of each cluster were examined through the average values of the factor scores per group and the central points of each cluster. Cluster 1 regarded time and situational values as being more important than Cluster 3, while showing the second-highest value among the three clusters in terms of convenience value. For this reason, it was named pursuing-simplicity-and-convenience type. Cluster 2 considered health, packaging design, and convenience value important, and, compared to other clusters, it put more weight on family values than the pursuing-simplicity-andconvenience cluster and indicated a higher time value than Cluster 3. As for food consumption, as the cluster appeared to consider diverse factors in general, it was named the considering-multiple-options type. Finally, Cluster 3 put more weight on family values than the cluster pursuing simplicity and convenience. Although there was no significant difference, this indicated that they thought the highest value was in safety, and this was named the pursuing-family-safety type accordingly.

Comparison of Preference by HMR Type and by Cluster
As a result of analyzing the preferences by dividing the HMR types into RTE, RTH, RTC, and RTP, the preference for RTH was 5.74 (1 = not preferred at all, and 7 = very much preferred), and the preference for RTE was 5.71. In terms of the differences in the preferences for each HMR type by cluster, the cluster pursuing simplicity and convenience and that considering multiple options showed a statistically significantly higher preference for RTH than the cluster pursuing family safety; the cluster considering multiple options presented a statistically significantly higher preference for RTC than the other clusters. In addition, the pursuing-family-safety-type cluster indicated a statistically significantly higher preference for RTP compared to the pursuing-simplicity-and-convenience-type cluster.

Importance of HMR Selection Attributes
Analyzing HMR selection attributes by using a seven-point Likert scale (1, as not important at all, to 7, as very important) shows that items such as taste (6.25), quality (6.36), expiration date (6.36), sanitation (6.29), nutrients (6.06), and freshness (6.07) have high levels of importance. When analyzing the differences by cluster, we see that the remaining items, except for taste, quality, diversity, quantity, price, sanitation, and ease of storage, have statistically significant differences.
The multiple-options cluster had statistically significantly higher average values than the pursuing-simplicity-and-convenience and pursuing-family-safety clusters in all items except for expiration date. In terms of each item of selection attributes, the importance of texture (6.02), packaging (5.81), organic (6.08), and preparation process (6.10) attributes is significantly higher statistically in the cluster considering multiple options, compared to other groups. In addition, the considering-multiple-options-type cluster showed a statistically significantly higher importance than the cluster pursuing simplicity and convenience in items such as additives (6.01), ingredients (5.66), brand (5.97), production methods (6.04), nutrients (6.26), and freshness (6.25).
The cluster pursuing family safety showed a statistically significantly higher average value than other groups in the item of expiration date (6.57) and a statistically significantly higher average value than the pursuing-simplicity-and-convenience type for nutrients (6.26). The pursuing-simplicity-and-convenience types showed a statistically significantly lower average value than considering-multiple-options types in all items, except for preparation time (5.80) (Appendix A Table A2).

Performance of HMR Selection Attributes
As a result of analyzing the importance of HMR selection attributes, again using a seven-point Likert scale (1, not satisfied at all, to 7, very satisfied), items such as taste (6.18), quality (6.28), expiration date (6.26), and sanitation (6.15) showed a high level of performance. However, packaging (5.61), organic (5.61), production (5.65), additives (5.72), and texture (5.76) showed a low level of performance. As a result of analyzing the differences by cluster for the performance of HMR selection attributes, there was no statistically significant difference between clusters in the quality, diversity, quantity, and price items, but there was a statistically significant difference between clusters in the remaining performance items. The multiple-options-type cluster showed statistically significantly higher performance than other groups in the items of additives (6.14), packaging (6.01), organic (6.01), preparation (6.04), and production (5.99) methods.
Furthermore, the cluster containing multiple-options types showed statistically significantly higher performance for taste (6.35), ingredients (6.11), and total (6.08) compared to the ones pursuing simplicity and convenience. In terms of expiration date and sanitation, the cluster pursuing family safety showed significantly higher performance statistically than the one pursuing simplicity and convenience. The pursuing-simplicity-and-conveniencetype cluster showed statistically significantly lower performance than the others for items such as ease of storage (5.61), nutrients (5.48), and freshness (5.57). For the preparation-time item, the cluster considering multiple options showed significantly higher performance statistically than the one pursuing family safety. In terms of branding, the cluster considering multiple options indicated a statistically significant higher performance than the one pursuing simplicity and convenience (Appendix A Table A3).

Analysis of Differences between the Importance and Performance of HMR Selection Attributes
As a result of analyzing the difference between the importance and performance of HMR selection attributes, among the total of 19 items, the cluster pursuing simplicity and convenience had 17 items with positive values, the one considering multiple options had 11 items, and the one pursuing family safety had 14 items (Table 5). This pattern means that overall performance was lower than importance. Among the HMR selection attributes, there was a significant difference in the variation between importance and performance by cluster for taste and ease of storage. In the taste item, the cluster pursuing simplicity and convenience showed a larger difference between importance and performance than other groups; as it indicated a positive value, the satisfaction level was lower than its importance. For the ease-of-storage item, the multiple-options cluster showed a greater difference between importance and performance than the other two groups. In addition, since the value of the ease-of-storage item in the cluster considering multiple options was negative, its performance was higher than its importance. Nevertheless, as the pursuingsimplicity-and-convenience group showed a positive value in terms of the difference between importance and performance in the ease of storage item, improvement is required to increase the performance of the ease-of-storage variable. Table 5. Analysis of differences between importance and performance of HMR selection attributes (mean ± SD).

IPA of Importance and Performance of HMR Selection Attributes
The importance-performance analysis of the HMR selection attribute items was conducted via the IPA technique, which places the results in a grid diagram. For the effective evaluation of each item, scores from 1 to 7 were given to both importance and performance, and the evaluation results are presented as shown in Figures 1-3 [71]. To create the IPA grid, the average values of the importance attributes were placed on the y-axis, and the average values of the performance attributes on the x-axis; the points of contact were selected and placed in four quadrants, using the importance and performance scores of each attribute.
The data on the pursuing-simplicity-and-convenience cluster showed that, in the first quadrant, both importance and performance were higher than average, and the current status can be maintained. This includes the following items: taste, quality, diversity, price, expiration date, preparation time, and sanitation. In the second quadrant, which had high importance but low performance, the following items were included: ease of storage, nutrients, and freshness. The items evaluated as having low importance and performance were quantity, additives, ingredients, packaging, organic, brand, preparation process, and production methods and are found in the third quadrant. The texture item belongs in the fourth quadrant, which is an area with low importance but high performance.   In the group considering multiple options, the first quadrant, in which both importance and performance were higher than average and the current status can be maintained, included items such as taste, quality, expiration date, sanitation, nutrients, and freshness. The items to be improved in the future are shown in the second quadrant, which has high importance but low performance: price, ingredients, and preparation time. On the other hand, the items evaluated as having low importance and performance were found in the third quadrant: texture, diversity, quantity, packaging, organic, brand, preparation process, and production methods. Additives and ease of storage belonged to the fourth quadrant, with low importance but high performance.   In the cluster pursuing family safety, the first quadrant has both importance and performance higher than average-meaning the current status can be maintained-and included the following items: taste, quality, price, expiration date, sanitation, ease of storage, nutrients, and freshness. In the second quadrant, with high importance but low performance, meaning further improvement is required, ingredients were included. The items evaluated as having low importance and performance were found in the third quadrant: texture, quantity, additives, packaging, organic, brand, preparation process, preparation time, and production methods. The diversity item belonged in the fourth quadrant, with low importance but high performance.

Demand for HMR Product Development
As a result of analyzing the demand for HMR product development by using a sevenpoint scale (1 = not desired at all, and 7 = highly desired), the following items showed high demand for product development: reinforced nutrients (6.23), eco-friendliness (6.03), various menus (5.93), organic (5.89), calorie control (5.82), premium (5.79), meal kit (5.72), and small packaging (5.58) ( Table 6). As for the differences by cluster in the second quadrant, which requires improvement due to its high importance but low performance, the ease-of-storage item was included due to the characteristics of the pursuing-simplicity-and-convenience type group. Since nutrients and freshness also belonged to the second quadrant, the key factors of food exerted a strong influence on selection attributes, even if the cluster preferred simple and convenient products. As for the other two clusters, ingredients were included in the second quadrant. The two groups were concerned about the health and safety of the family, but, because of the nature of HMR products, it is difficult to precisely identify the ingredients in some products; this means that there should be measures put in place to improve performance by improving reliability on this issue.

Demand for HMR Product Development
As a result of analyzing the demand for HMR product development by using a sevenpoint scale (1 = not desired at all, and 7 = highly desired), the following items showed high demand for product development: reinforced nutrients (6.23), eco-friendliness (6.03), various menus (5.93), organic (5.89), calorie control (5.82), premium (5.79), meal kit (5.72), and small packaging (5.58) ( Table 6). Table 6. Demand for HMR product development (mean ± SD). As a result of analyzing the differences in the demand for HMR product development by cluster, no statistically significant difference was found between clusters for reinforced nutrients and various menus. However, the demand for products with reinforced nutrients was 6.23 out of 7.0, which showed the highest average value, while the item of various menus (5.93) indicated the third-highest demand value among the total items; thus, HMR product development should focus on reinforced nutrients and diversity.

Considering-Multiple-Options Type
There was a statistically significant difference in demand per cluster for all items, except for those of reinforced nutrients and various menus. The cluster considering multiple options showed a higher average value than the other groups in all items with statistically significant differences. This indicates that the overall demand for HMR product development is high. As for the differences by detailed items, the cluster considering multiple options showed a statistically significant higher demand for the following items than the other clusters: calorie control (6.15), dried food (6.09), meal kit (6.10), small packaging (6.01), low sugar (5.95), low sodium (5.91), low-calorie (5.88), and therapeutic diet (5.72).
Furthermore, the group considering multiple options indicated a statistically significant higher demand for the following items, compared to the group pursuing simplicity and convenience: eco-friendly (6.26) and organic products (6.21). However, this cluster showed an overall lower average value in the demand for product development, compared to other groups; in particular, the demand for premium (5.40) and functional (4.91) products was significantly lower statistically.

Discussion
This study provides basic data on the direction of HMR product development and the establishment of marketing strategies in the Vietnamese market through market segmentation in line with the FCV of Vietnamese single-member households. It also analyzed HMR-product-related consumption behavior for the segmented market. As a result of analyzing Vietnamese single-member household consumers who had HMR experience and regularly used HMR products, there were differences in HMR consumption behavior by cluster.
The pursuing-simplicity-and-convenience type prioritizes convenience, quality, and price in food consumption and has the characteristic that food choices can vary depending on the situation. The considering-multiple-options type tends to consider a range of factors, such as family, health, safety, and convenience. The pursuing-family-safety type places importance on safety and family, and also considers price and product. In studies that attempt market segmentation for single-member households, using lifestyle, food-related lifestyle, and consumption value, we see that convenience, health, economy, safety, and quality are major factors in market segmentation, similar to the pattern found by this study [72][73][74].
However, they differ from this study in that our results show that the family functions as a major factor in food consumption. In particular, the influence of the family is large in the consideration-of-multiple-options type and the pursuing-family-safety type. Compared to European and North American countries, Vietnam places more importance on family [57], but this characteristic can exist in all countries. Accordingly, consumer insights should be derived through qualitative research and the development of a market segmentation scale that considers consumer characteristics, so that national characteristics and differences can be included when performing market segmentation.
Among the food-consumption values, safety, price and product, and convenience were important values in food consumption in all clusters. According to Lee [75], who studied consumption value perception for single-member households, single-member households show a high orientation toward efficiency, including price, product quality, and functional factors. Consequently, it would be desirable in future studies to focus on efficiency and convenience when developing a strategy to promote HMR consumption for single-member households.
As for the preference per HMR type, there were high results for both RTE and RTH products. RTE and RTH are the products with the highest convenience among the four HMR products, and this means that single-member households prefer products with high convenience. According to Meallinson et al. [76], there are many single-member households in the category of kitchen evaders, and their dependence on convenience food is high, supporting the results of this study.
The consideration-of-multiple-options type showed a high preference for RTC, and the pursuing-family-safety type showed a high preference for RTP. According to Kang and Lee [77], convenience-oriented consumers consume more food products based on convenience than health-oriented consumers. Among the market segments of this study, the pursuing-simplicity-and-convenience type is similar to convenience-oriented consumers, and the considering-multiple-option types is a group similar to health-oriented consumers. Moreover, the behavioral characteristics are similar in that the pursuing-simplicity-andconvenience type had a lower preference for RTP products that require the most cooking and preparation processes among the four HMR types. In other words, the degree-ofconvenience orientation differs according to the characteristics of the segmented market.
However, this study's results have limitations in deriving unambiguous evidence that reveals differences in preference for HMR types by segmented market for single-member households. Consequently, follow-up studies on the relationship between the characteristics of each segmented market and their preference for convenience food types are needed. In addition, it is necessary to expand the analysis to various products differentiated by main ingredients and cooking method.
Regarding the importance of HMR selection attributes, the group considering multiple options considered various selection attributes as being more important than the other groups. According to Hong and Choi [72], the well-being-seeking consumer, similar to the multiple consideration type in this study, considered several factors, such as shelf life, country of origin, ingredients, nutrients, food additives, and certification mark, as important when choosing food. This means that interest in diet has a profound influence on food-consumption behavior. Moreover, Rathee et al. [78], who studied the perception of HMR products, indicated that female employees were found to be influenced by diverse factors when purchasing HMR products. These include factors such as nutrients, health, usefulness, ease of use, price, timesaving, taste, and familiarity. As with single-member households, the research targets in this study, female employees, also faced a lack of time due to their busy workload; they eventually purchased HMR products to avoid more work preparing their own meals at home.
However, as they seriously considered several factors when purchasing HMR products, such behavior is similar to that of the multiple-options-type group in this study. Lee and Hong [79] pointed out gender differences, according to which female consumers considered attributes such as "fresh ingredients", "convenient food intake", and "reliable brand" more seriously than male consumers. However, in contrast to studies in which food quality and nutrients were important selection attributes, Lee and Lee [80] showed that college students, as research targets, chose food that satisfied their preferences, rather than food quality and nutrients. Along with differences due to gender and age, as revealed in this study for single-member households, there are also differences in line with FCV in the segmented market. In summary, there may be differences in the importance of HMR selection attributes depending on consumer characteristics and, accordingly, detailed research and analysis of target consumers is required.
As a result of analyzing the differences between the importance and performance of HMR selection attributes, the level of performance was lower than that of importance; an overall improvement is thus required. In particular, the ease of storage, nutrients, freshness, ingredients, price, and preparation time require high overall performance. Park et al. [81] studied the perception of HMR quality and emphasized the need for priority improvement of price, capacity, safety, and product-quality factors. It is necessary to improve the quality of the product and satisfy the consumer's demands for ease of storage and preparation time, which are convenience-related attributes that single-member households value.
In terms of the demand for product development, items such as reinforced nutrients, eco-friendliness, and variety in menus are considered important. In particular, the multipleoptions-type cluster indicated a high demand for product development, such as reinforced nutrients, premium, low sugar, and low sodium; this group already indicated a tendency to consider family, health, safety, and convenience in food selection.
As for the overall characteristics of the segmented market, family influenced choosing HMR products, despite the characteristics of single-member households, thus reflecting the family-oriented culture of Vietnam. The characteristic that places importance on the family can be seen in all countries in varying degrees, so it is necessary to conduct followup studies on the differences in the influence of families when purchasing convenience food for each country and culture. Furthermore, despite the distinctive characteristics of the market segments, taste, expiration date, sanitation, and nutrients are considered essential in selecting HMR products. In terms of HMR product development, it is desirable also to focus on product quality factors (e.g., taste and nutrients) and food-safety-related factors for building reliability (e.g., expiration date and sanitation). Furthermore, since single-member households are a group with heterogeneous characteristics [82], it is necessary to devise a differentiated strategy through market segmentation in consideration of these characteristics.

Theoretical Contributions
Vietnamese consumers have shown an increasing preference for the consumption of HMR products, due to economic development, urbanization, and higher income levels. In particular, it is expected that the shrinking household size and the increase in single-member households would bring changes in the Vietnamese HMR market. In developed countries, where single-member households have already grown significantly, such households are being evaluated as the new main consumers in the market [7][8][9]; the influence of singlemember households is also expected to increase in the Vietnamese food market. However, there has been limited research on the changes in the Vietnamese HMR market driven by shrinking household size, and there is no research on the food consumption of singlemember households. In this regard, this study is significant, as it can be useful as basic data for future related research.
Market segmentation through FCV of single-member households in Vietnam shows that values such as family, health, price and product, time, packaging, safety, convenience, and situation can explain their FCV. In particular, family and situational values have significant implications. The cultural and historical background of Vietnam contributed to the formation of family value, and this value influences food consumption [83][84][85]. In addition, the situational value reflected climatic characteristics, such as Vietnam's tropical monsoon climate and rainy season. This study found that family value and situational value can be useful measurement tools for market segmentation related to food consumption and dietary life, so an analysis tool reflecting the culture, history, and climatic characteristics of the target market should be utilized for market segmentation, using FCV. Moreover, as the influence of family value on food consumption was significantly lower in the cluster pursuing simplicity and convenience than in the other two, additional studies are needed. Although people are born and raised in the same cultural and historical background, there can be a significant difference in creating their FCV, depending on their experiences while growing up. For this reason, in terms of research on FCV, analyses of the impact of growth background on FCV must be conducted.

Managerial Implications
This study provides practical implications for market segmentation and securing the market competitiveness of single-member households, which are likely to become mainstream consumers in the Vietnamese HMR market in the future.
First, to secure competitiveness in the HMR market for single-member households, it is necessary to identify consumption values reflecting the characteristics of these households. Compared with developed countries, where single-member households are already dominant, these households in Vietnam can be evaluated as less dominant and marketable. However, since the shrinking household size and the increase in single-member households can be global trends, understanding their FCV in Vietnam can be an appropriate strategy to respond to future market changes. In particular, there may be differences in the value system related to the food consumption of single-member households, in contrast to general households. This shows that the identification of FCV, market segmentation, and analysis of market characteristics can be an effective means to secure competitiveness in the Vietnamese HMR market.
Second, when segmenting the market for single-person households, the focus should be on convenience. The pursuing-simplicity-and-convenience type in this study showed a tendency to prefer products with high convenience, while they were reluctant to put a lot of labor into preparing and organizing meals in their HMR consumption behavior. In addition, they demanded improvement in the ease of storage. While the consideringmultiple-options type took care of several factors, along with convenience, when consuming HMR, the pursuing-family-safety type did not consider convenience as important compared to other groups. Convenience is thus a major influence on food consumption, due to the hectic daily life of modern people [12,29]. Accordingly, convenience orientation can be the most effective criterion among market segmentation factors.
Third, the market can be segmented according to the characteristics of Vietnamese single-member households, but irrespective of this segmentation, the factors that all consumers seriously consider when purchasing HMR products should be highlighted. According to the results of this study, among HMR types, there is a preference for RTE and RTH products; thus, when launching HMR products for single-member households, it is desirable to select RTE and RTH as priority products and expand these types in line with future market demand. In addition, when selecting HMR products, taste, quality, expiration date, sanitation, nutrients, freshness, and diversity are highly important in the total segmented market. To do this, it is necessary to first reflect consumer demand for the abovementioned items when developing HMR products for single-member households. Furthermore, considering that HMR selection attributes such as ease of storage, nutrients, freshness, price, ingredients, preparation time, and ingredients indicate lower satisfaction levels than importance levels, improving the currently released products should focus on these items first.
Finally, estimating the FCV of Vietnamese single-member household consumers shows that it is important to make efforts to match the value of HMR products. To attain market competitiveness, it is also necessary to devise marketing strategies in accordance with Vietnamese consumers' FCV.

Limitations and Future Research Directions
As there is no HMR-related research on Vietnamese single-member households, this study is significant in that it measured the FCV reflecting Vietnamese cultural and climatic characteristics and identified the characteristics of HMR market segmentation in Vietnam. However, it has limitations in that the 250 survey subjects cannot represent all singlemember households in Vietnam, and thus there may be several features that are not revealed via the tool for measuring FCV in this research. In follow-up studies, it will be necessary to expand the number of subjects and derive market characteristics that are not identified in this study. In addition, follow-up studies should be conducted to diversify HMR consumption-behavior measurement items and add specific and detailed items. Since there may exist differences between single-person households and multi-person households [86] in food-consumption behavior, follow-up studies according to household size need to be conducted.
Understanding the development and changes in the tourism market and securing insights into particular market segments is crucial in securing competitiveness. It is expected that the results of this study (i.e., the characteristics of segmented markets and consumers' attitudes, behaviors, and demands) can contribute to determining the direction of market tailored HMR product development and to deriving relevant marketing strategies.  Data Availability Statement: Data sharing not applicable.

Conflicts of Interest:
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.