VIETNAM NATIONAL UNIVERSITY, HANOI INTERNATIONAL SCHOOL STUDENT RESEARCH REPORT FACTORS INFLUENCING HOUSEHOLD FOOD WASTE BEHAVIOR: AN APPLICATION OF THE EXTENDED THEORY OF PLANNED BE
INTRODUCTION
Background of the study
Food waste is defined as discarded edibles, including inedible fractions, that are removed from the supply chain for recovery or disposal (Stenmarck et al., 2016) According to FAO (2013), food waste refers to edible food being discarded regardless of its expiration status or spoilage This waste stems from various factors, including spoilage, market oversupply, and consumer habits Food waste poses a critical challenge for global food security and environmental governance due to its significant environmental, economic, and social consequences (Stenmarck et al., 2016).
Many studies have evaluated the consequences of food waste in many ways The study by FAO (Food and Agriculture Organization of the United Nations) has estimated that the amount of emissions (CO2) released into the environment when producing wasted food is up to 3.3 Gtonnes (FAO, 2013) This is equivalent to the fact that, if “food waste” were a country, this country's amount of emissions into the environment would rank third in the world, just behind the US and China (FAO, 2013) FAO also pointed out the data based only on producer prices, the direct economic cost of food waste in agriculture (excluding fish and shellfish) is around USD 750 billion, which is similar to Switzerland's GDP (FAO, 2013) Moreover, according to The United Nations Environment Programme's 2021 Food Waste Index (UNEP), in 2019, about
931 tons of food waste was released into the environment in the world, of which it is estimated that 61% of it is waste from households ((WRAP) et al., 2021) From this data, the report points out that this accounts for 17% of total global food waste, of which 11% comes from household food waste((WRAP) et al., 2021)
UNEP's data shows that the household food waste index accounts for the majority of total food waste worldwide A wide variety of negative consequences have occurred One of them is the social impact since it contributes to rises in global food costs, making food less available for the poorest, and increasing the number of hungry individuals in both developed and developing nations (Graham-Rowe et al., 2014) Furthermore, the effects of wasting food in general, and household food in particular, directly affect the environment (FAO, 2013) Food waste is one of the causes of water waste(FAO, 2013) Besides, the report also points out that food produced but not used or used unreasonably accounts for nearly 1.4 billion hectares of land This has increased negative impacts on land use (e.g monoculture, agricultural land expansion, ) causing ecological imbalance, including for mammals, birds, fish and amphibians(FAO, 2013)
In Vietnam, a survey conducted on a scale of 4,000 households in eight countries in the Asia- Pacific region showed that Vietnam is the second country in terms of food waste index (Waste,
2024) FoodBank Vietnam's survey shows that 87% of Vietnamese households admit to wasting at least two plates of food per week Accounting for the largest proportion in the chart of wasted foods is rice, vermicelli, pho, and noodles with an estimated figure of up to 68% of household food waste Next is cooked fish meat at 53% and vegetables at 44% (Thảo, 2022) Vietnam's capital, Hanoi, is one of the most active cities in Asia and the Pacific, with relatively significant
3 economic development that is predicted to accelerate in the future years However, the city is facing many challenges related to environmental pollution, and one of them is food waste According to statistics from the Hanoi Urban Environment Company (Urenco) in 2023, Hanoi city generated about 7,000 solid wastes per day (2,555,000 tonnes/year), of which food waste is 3,600 tons, accounting for about 51.9% of the waste(HanoiTimes, 2023) As a result, the city has several difficulties connected to economic growth, environmental protection, and agricultural and food system sustainability, including food security, food safety, and food waste, as well as waste management and quality of life (Liu & Nguyen, 2020)
Despite recognizing this urgent problem, there is little research on the factors causing household food waste in Hanoi The previous study has indicated the responsibility for food waste that can be attributed to agriculture and the later stages of the supply chain varies by literature, but in summary, customer behavior is regularly identified as a primary contributor to the problem (Delley & Brunner, 2017) Several studies have applied Ajzen's Theory of Planned Behavior (TPB) (Ajzen, 1991a) to predict and explain factors leading to food waste behavior in households The theory's central thesis is that subjective norms, attitude, and perceived behavioral control all impact an individual's purpose, which subsequently results in the behavior of that individual Furthermore, Ajzen contends that TPB encompasses additional structures beyond the base model (Ajzen, 1991a)
A study by author Aysen Coskun et al also applied the TPB model to research the factors affecting food waste behavior in the restaurant context The author theorizes that the correlation between concern about price (Filimonau et al., 2017) and the taste of food (Heikkilọ et al., 2016) will affect the intention to waste food in a restaurant context As a result, the study extended the TPB model with two variables predicting that price consciousness and food taste will affect intentions and behaviors to reduce food waste (Coskun & Ozbuk, 2020) The results of this investigation show that perceived behavioral control has the greatest impact on both food waste intention and behavior Predictors of intention to reduce food waste including price consciousness and attitudes toward food waste were reliable Food taste has a significant impact on both intention and behavior, but its impact on intention to reduce food waste differs from the hypothesis (Coskun & Ozbuk, 2020)
A similar study conducted by Chih-Ching Teng et al in the context of Taiwanese households points to the problem of the intention-behavior gap as an improvement on Ajzen's TPB model (Teng et al., 2020) The author found that the TPB literature on household food waste shows no consistent results regarding the relationship between ethical standards, intention to reduce food waste, and food waste The study concluded with the result that ethical standards have a significant positive impact on family food preservation and cooking habits Besides, household food waste was significantly impacted negatively by perceived behavioral control Finally, the research also validates the function of home cooking and storing practices as a moderator of the relationship between food choices, moral norms, and food waste (Teng et al., 2020)
However, both studies have not shown which factors impact the subjective norms and the attitude toward food waste, which likely indirectly influence food waste intentions and behavior Therefore, this study was conducted on households in Hanoi, to investigate which factors affect people's subjective norms and attitudes towards food waste, thereby investigating whether and how those factors impact consumer intentions and behavior in wasting food in households
While the Theory of Planned Behavior is an ideal theoretical framework for investigating both human intentions and behavior, Ajzen believes that the current form of the TPB is still not the most accurate (Ajzen, 1991) Therefore, the current model of this form can be flexibly changed based on the research background (Ajzen, 1991) In this research, we will aim to provide an extension for the Theory of Planned Behaviour, which include social norm, domestic education, environmental concern, and time pressure Expanding the research model based on the original TPB model can help predict factors affecting household food waste intention and behavior in Hanoi to become more specific and accurate.
Contribution of the study
This study employs the Theory of Planned Behavior (TPB) to examine the direct and indirect drivers of household food waste in Hanoi Building on the TPB's original framework, the model is expanded to address research gaps identified in prior studies The TPB postulates three independent variables (subjective norms, attitudes, and perceived behavioral control) and two dependent variables (intention and behavior) Notably, this study extends the TPB by analyzing factors influencing two of these independent variables: subjective norm and attitude By doing so, the model's predictive power in capturing household food waste behavior is enhanced.
The results of the research bring many contributions to society First of all, research tends to provide insights into consumer behavior, helping firms better understand the reasons why consumers waste food Moreover, they can develop effective marketing strategies to encourage consumers to use food sparingly Furthermore, research contributes to enhancing food security and reducing production costs for businesses Research helps policymakers come up with effective solutions to reduce food waste and ensure food security for people Besides, it can be the data for businesses to identify the causes of food waste, thereby providing solutions to reduce waste and save costs Last but not least, the results of this research aim to promote sustainable social development Reducing food waste is one of the United Nations' sustainable development goals, thereby promoting sustainable development and contributing to build a better future.
Objective of the research
The study aimed to investigate the factors affecting food waste behavior in the Hanoi area Specifically, it refers to the accomplishment of the following goals:
1 Analyse demographic data of Hanoi people through:
2 Assess the relationship between factors affecting household food waste behavior of Hanoi residents
3 Test the relationship between factors affecting subjective norms (including social norms and domestic education) and factors affecting attitudes toward food waste (including
5 environmental concern and time pressure) and perceived behavioral control, thereby influencing household food waste intentions and behavior
4 Recommending solutions to reduce household food waste.
Scope of the study
• Research object: The research focuses on the food waste behavior of individuals who used to or are currently living in Vietnam
• Research content: research on factors leading to food waste behavior of people in Hanoi
The study includes an investigation of the impact of social norms and domestic education on subjective norms In addition, the study investigated the relationship between environmental concerns and time pressure on people's attitudes towards food waste From the above data, the study explores the influence of social norms, consumer attitudes, and perceived behavioral control on household food waste intentions and behavior
• Research method: Distribute a 5-Likert scale survey questionnaire to people to collect information about food waste behavior and factors affecting this behavior.
• Research area: The study is conducted in northern region of Vietnam, mainly the central capital and its surrounding provinces.
Research organization
This research includes 5 chapters: introduction, literature review, research methodology, result and discussion, and conclusion
The introduction chapter contains the backgrounds of the study, the definitions of teams, the contribution of the study, the objective of study, the scope of the study and the research organization
The literature review chapter clearly shows the theoretical foundations used to research this topic The study shows the basic TPB theory, in addition to the specific explanation of each variable of the research model Besides, it indicates the hypotheses that will be evaluated in the research and articles related to the topic research
The research methodology chapter discusses the research methods that are conducted in this research including research models, data collection methods, measurement, population and sample size, and the data analysis technique
Results and discussion chapter explains the data collected from the data processing in the previous chapter, then the results will be presented in a clear, transparent, and understandable way
The conclusions and recommendations chapter will conclude with an explanation of the research's conclusion, a discussion of the findings following analysis, and helpful business recommendations based on the conclusions drawn In addition, research notes its shortcomings as well as those for future investigations
LITERATURE REVIEW
Theory of Planned Behavior
The Theory of Planned Behavior (TPB), developed by Icek Ajzen, postulates that an individual's behavior is primarily influenced by their intentions These intentions are shaped by subjective norm (perceived social pressure), attitude toward the behavior, and perceived behavioral control (confidence in one's ability to perform the behavior) According to TPB, intention is the primary factor that drives human behavior, reflecting the individual's willingness and effort to engage in a specific action.
The theory of planned behavior defines the concept of three independent factors that influence intention First of all, the attitude toward behavior “refers to the degree to which person has a favorable or unfavorable evaluation or appraisal of the behavior in question”(Ajzen, 1991a) The second factor is the subjective norm which “refers to the perceived social pressure to perform or not to perform the behavior”(Ajzen, 1991a) Finally, perceived behavior control indicates “the perceived ease or difficulty of performing the behavior and it is assumed to reflect past experience as well as anticipated impediments and obstacles” (Ajzen, 1991) The addition of perceived behavior control is a difference of TPB from the Theory of Reasoned Action (TRA), which is given to explain behavior based on more than just the individual's volitional control(J.Madden et al., 1992)
Figure 1: Theory of Planned Behavior (Source: Ajzen 1991)
The Theory of Planned Behavior (TPB) provides a framework for understanding food waste behavior TPB postulates that attitudes, subjective norms, and perceived behavioral control influence an individual's intention to perform a behavior, in this case, food waste Attitudes are based on the beliefs and feelings associated with the behavior; subjective norms are influenced by the approval or disapproval of significant others; and perceived behavioral control reflects the individual's belief in their ability to perform the behavior Research suggests that negative attitudes towards food waste, perceived social disapproval, and high perceived behavioral control can reduce waste intentions.
7 specifically that individuals will decide to reduce food waste more(Baronea et al., 2019; Coskun
& Ozbuk, 2020; Graham-Rowe et al., 2015) Finally, perceived behavioral control in research on food waste behavior assesses the degree to which the individual perceives that the behavior of reducing food waste is easy or difficult to perform Intention to reduce food waste increases when an individual realizes that the factors that cause food waste are beyond his/her control (Aktas, Topaloglu, et al., 2018; Baronea et al., 2019; Coskun & Ozbuk, 2020; Graham-Rowe et al., 2015)
In the realm of household food waste, the Theory of Planned Behavior (TPB) has gained significant traction as a framework for understanding waste-related behaviors Seminal research by Graham-Rowe et al highlights the crucial role of attitudes, subjective norms, and perceived behavioral control in shaping individuals' decisions to reduce fruit and vegetable waste These factors serve as significant determinants in predicting household food waste behavior, underscoring the theory's relevance in this context.
2015) The relationship between food waste and elements of the TPB theoretical framework was confirmed in research conducted by Aktas et al among households in Qatar(Aktas, Topaloglu, et al., 2018) Another study by Chih-Ching Teng et al conducted in Taiwan applied the TPB theoretical model to investigate the determinants that promote food waste prevention in households Research has shown that perceived behavioral control has the greatest impact on both food waste intention and behavior(Teng et al., 2020)
The Theory of Planned Behavior (TPB) offers a valuable framework for understanding human intentions and behaviors However, Ajzen (1991) acknowledges that the current model requires refinement To address this limitation, researchers have proposed extending the TPB to incorporate additional factors, including social norms, domestic education, environmental concerns, and time pressure These extensions aim to enhance the model's accuracy and applicability across diverse research contexts.
Related researches
Table 1: Previous studies relating to research
Authors Year Title Study focuses Method Results
2020 What influences consumer food waste behavior in restaurants? An application of the extended theory of planned behavior
It identifies problems such as the intention to reduce food waste and food waste behavior in restaurants
The study provided an online survey which collected quantitative data from 333 participants and just 329 responses were usable First, the measurement model using a confirmatory factor analysis (CFA) was assessed to ensure construct reliability and validity
After that, structural equation modelling was conducted to test the hypothesized relationships using AMOS 21.0.
A novel model proposed by researchers pinpoints five key factors driving the intention to reduce food waste at restaurants: attitudes, perceived behavioral control, food taste, and price consciousness These findings underscore the significant influence these determinants have on individual behavior, highlighting the importance of addressing them through targeted interventions aimed at promoting sustainable dining practices.
2019 The determinants of food waste behavior in young consumers in a developing country
The research seeks to understand the behavior of young customers regarding food waste and the factor influencing it
Via a website-based questionnaire, the data was collected A two-step structural equation modeling approach was utilized to analyze data
This paper discusses environmental concerns and time pressure affecting attitudes toward reducing food waste However, while attitudes and social norms influence intentions to reduce waste, moral norms, and perceived control do not significantly impact these intentions
2020 Examining household food waste behaviors and the
The study focuses on comprehending the psychological aspects of household food waste
The study analyses the first representative national-level household survey to provide insights and policy implications
The study identified two main motives for reducing household food waste: waste concerns and doing the right thing, and the
9 determinants in Korea using new questions in a national household survey (Kim &
Lee, 2020) behavior in the United Kingdom regarding their food purchasing habits The study's purpose is to guide household food waste reduction initiatives importance of food management skills Barriers included a 'good' provider identity, inconvenience minimization, lack of priority, and exemption from responsibility
2022 Analysis of factors influencing residents' waste sorting behavior: A case study of Shanghai
This study aims to expand the existing body of knowledge on waste sorting intentions and behaviors among residents of Shanghai By extending the Theory of Planned Behavior (TPB), the research model developed in this study intends to provide a more comprehensive understanding of the factors influencing these behaviors The TPB, a well-established theory in social psychology, postulates that an individual's intention to perform a behavior is influenced by three main determinants: attitudes toward the behavior, subjective norms, and perceived behavioral control This study incorporates additional variables, such as knowledge, environmental awareness, and perceived responsibility, to enhance the explanatory power of the TPB model specifically in the context of waste sorting behaviors.
This article analyzes data using SPSS 25.0 and Amos 26.0 To get the necessary information, this work employs a questionnaire research method
The study discovered that attitudes, subjective standards, and perceived behavioral control all had a favorable and substantial effect on Shanghai people's desire to sort garbage It also demonstrated that sorting behavior is impacted by sorting intention, with high intent boosting the chance that people will sort garbage
2021 Uncovering residents and restaurants’ attitude and willingness toward effective food waste management: A case study of Macau (Liang et al., 2021)
The paper discusses people's attitudes and willingness in managing food waste, covering both household and restaurant contexts
The research collected data via a survey that included 4 sections
Finally, a binary logistic regression model was improved to perform regression analysis on respondents' WTP and identify significant influencing factors by using both qualitative and quantitative variables
There are two main reasons of food waste are expired food date and excessive ordering, both in household and restaurant contexts
In addition, vegetables and fruits are the most wasted foods The research also indicates that income level has a appears as a significant influence on inhabitant’s behavior, with age and education level showing a negative correlation
2023 Analyzing the food waste reduction intentions of UK households A Value- Attitude-Behavior
(VAB) theory perspective (Habib et al., 2023)
This research utilizes the Value-Attitude-Behavior (VAB) theory to understand UK households' intentions regarding food waste reduction The study investigates the influence of perceived values, anticipated guilt, and social norms on attitudes and intentions towards reducing food waste By considering these factors, the research aims to identify the drivers and barriers to household waste reduction and provide insights for designing effective interventions.
The research utilized Covariance- Based Structural Equation Modeling (CB-SEM) with IBM SPSS AMOS
The results of the study validate a positive correlation between perceived value and attitude, whereby emotional incentives stimulate perceived value, leading to a propensity for food waste reduction efforts driven by guilt Moreover, adherence to societal norms fosters alignment of attitude with pro-social conduct, and attitude notably shapes favorable inclinations towards food waste reduction endeavors
Hypotheses
The Theory of Planned Behavior highlights the importance of personal control in shaping intentions and behaviors (Ajzen, 1991b) Ajzen believes that personal attitudes about particular actions engage into the intentions to perform certain behavior (Ajzen, 1991b) Studies proved that an individual with a positive attitude has a strong intention to put behavior into effect, while the intention of a person with a negative opinion is weakened (Hatice Aydin, 2022) (Ivana Blešić, 2021; Violeta Stefan, 2013; Vivianne H.M Visschers, 2016)
Incorporating environmental attitudes into the Theory of Planned Behavior (TPB) model enhances its ability to predict individuals' environmental behaviors Environmental concerns particularly influence attitudes towards food waste Individuals are more likely to intend to reduce food waste when they are aware of its negative environmental consequences, leading to actions to minimize waste However, despite the importance of environmental awareness, its impact on reducing food waste remains limited due to low levels of awareness among consumers.
Moreover, many authors emphasized the role of time when a person finishes his/her meal Psychological factors contribute to the connection between time and appetite (Ivana Blešić,
2021) A person who lacks time to eat may lose their appetite When individuals are pressed for time, they may experience heightened stress levels and a preoccupation with completing tasks within the given timeframe This mental state can distract individuals from focusing on their hunger cues, leading to a diminished interest in food
The amount of food consumers waste also depends on the time constraints (Sujita Pandey,
2023) Studies have shown that the amount of food consumers waste is closely tied to the time available to consume it When individuals are rushed or have limited time to eat, they are more likely to leave portions unfinished or discard food entirely This wasteful behavior not only has financial implications for individuals but also contributes to broader issues of food scarcity and environmental sustainability
According to studies, one approach involves promoting structured meal schedules, where individuals are encouraged to follow regular breakfast, lunch, and dinner routines By offering meals at the right times of the day and establishing a consistent eating pattern, individuals are more likely to allocate adequate time for eating and experience improved appetite regulation (Ann C Wilkie, 2015)
Subjective norms play a significant role in influencing individuals' intention to reduce food waste These norms result from the perception that individuals have about the expectations of others regarding their behavior (Ajzen, 1991b) Factors such as willingness to comply and normative beliefs shape subjective norms However, research findings regarding the impact of subjective norms on food waste behavior are mixed, with some studies indicating a weak or non-existent relationship (Stefan, 2013; Visschers, 2016), while others suggest a positive influence (Ajzen, 1991b) Subjective norms reflect perceived social expectations for reducing food waste and can influence individuals' behavior positively.
When a person is under social pressure, she/he has a stronger intention not to waste food (Joana Simões, 2023) If someone doesn't meet or transgress socially or personally internalized ethical norms in the context of consuming, it may impact their behavior Accordingly, the person will endeavor to leave as little food waste as possible when individuals around them make an effort to reduce food waste
Domestic education is also an important factor that affects the subjective norms (Sujita Pandey,
2023) The awareness of reducing food waste rises with education level (Daniel Fοx, 2018) However, research found that a person with a higher education tends to leave a larger amount of food abandoned Due to their high levels of education, they earn more money and thus are more likely to over-spend and waste food In contrast, focusing on individuals with lower incomes and levels of education has a greater impact on changing consumer behavior related to reducing food waste (Sujita Pandey, 2023)
In order to broaden the application of TPB, the last premise of perceived behavioral control intention has been implemented This is because behaviors are not always categorized only according to an individual's will The degree to which an individual feels capable of carrying out an activity is referred to as perceived behavioral control Overall perceived behavioral control is formed by adding these beliefs to the perceived strength of each control aspect (Ajzen, 1991b)
As the influence exerted by various factors grows in magnitude, an individual's proficiency in carrying out a specific action is enhanced According to the TPB, the probability of an individual intending to engage in a particular behavior rises significantly when they perceive an ample degree of personal control over that behavior Adopting this perspective, we can examine an individual's intention and conduct in relation to the crucial issue of avoiding food wastage, which undoubtedly falls within their sphere of influence and control
When it comes to avoiding food wastage, an individual's sense of control plays a significant role The stronger their perception of control, the less likely they are to entertain intentions of wasting or minimizing food By nurturing a heightened sense of control, individuals can adopt responsible practices, make conscious choices, and actively contribute to reducing food waste for the benefit of the environment and society as a whole
The Theory of Planned Behavior (TPB) proposes that behaviors are influenced by attitudes, subjective norms, and perceived behavioral control Applied to household food waste, TPB suggests that individuals' attitudes towards food waste (e.g., its severity, consequences), their perception of how others view food waste, and their belief in their ability to reduce food waste are key factors influencing their behavior Additional factors identified in literature reviews include food management practices, such as storage and portion control, as well as socio-economic characteristics like income and family size.
Hypothesis 1 (H1): Intention to reduce food waste negatively affects food waste behavior Hypothesis 2 (H2): Subjective norms positively impact on individual’s intention to not waste food
Hypothesis 3 (H3): Attitude towards food waste negatively impacts on individual’s intention to not waste food
Hypothesis 4 (H4): Perceived behavioral control positively impacts on individual’s intention to not waste food
Hypothesis 5 (H5): Social norms positively impact on subjective norms
Hypothesis 6 (H6): Domestic education negatively affects subjective norms
Hypothesis 7 (H7): Environmental concern negatively affects attitude towards food waste Hypothesis 8 (H8): Time pressure negatively affects attitude towards food waste
Figure 2: Proposal model of research
METHODOLOGY
The Operational definition and Measure design
In Structural Equation Modeling (SEM), there are exogenous variables and endogenous variables According to (Bowen & Guo, 2011), exogenous variable is variable which is not explained or predicted by any other variables in the model An endogenous variable is defined as a factor in a causal model or causal system whose value is determined by the states of other variables in the system, contrasted with an exogenous variable Related but non-equivalent distinctions are those between dependent and independent variables and between explanandum and explanans (Lewis-Beck et al., 2004) Nine corresponding variables of the proposed research model are going to be examined in this subsection
Food waste behavior:** measured on a five-point Likert scale, reflects an individual's tendency to waste food.* **Intention to reduce food waste:** gauges the likelihood of an individual to take action to minimize food waste.* **Perceived behavioral control:** assesses an individual's belief in their ability to control their food waste behavior.* **Attitudes towards food waste:** captures an individual's feelings and beliefs about the importance of reducing food waste.* **Subjective norms:** measures the perceived social pressure to engage in or avoid food waste behavior.
Table 1: Dimensions and indicators of Food waste behavior (FWB)
1 FWB1 I usually finish food I serve myself New
If I have accidentally prepared too much food for myself to eat, I will find ways to avoid wasting the leftover food
If I do not know about the content of the food, I will try to eat the food anyway
4 FWB4 Wasting food would give me a bad conscience (Bhatti et al., 2023)
Table 2: Dimensions and indicators of Intention to reduce food waste (INT)
1 INT1 I intend not to leave food (Stancu et al., 2016)
2 INT2 I intend to waste food as little as possible (Bhatti et al., 2023)
3 INT3 I will try new strategies to waste less food in the future New
Table 3: Dimensions and indicators of Perceived behavioral control (PBC)
1 PBC1 Predicting food amount at food choice is easy (Visschers et al.,
2 PBC2 Finishing all the food on my plate is easy for me
3 PBC3 I could always finish all the food on my plate if I wanted to
Table 4: Dimensions and indicators of Attitudes towards food waste (ATT)
1 ATT1 It is necessary not to waste food—it can always be used in some way
It is immoral to throw away food while other people in the world are starving
3 ATT3 It upsets me when unused products end up in the waste bin
Table 5: Dimensions and indicators of Subjective norms (SUN)
People who are important to me find my attempts to reduce the amount of food wasted necessary
People who are important to me think that I am frugal when I try to eat all food from my plate
If I generate food waste, my family/friends would find it undesirable
Exogenous variables in this research include social norms, domestic education, environmental concern and time pressure The measurements for each variable are shown in Table 6:
Table 6: Dimensions and indicators of exogenous variables
No Variables Items Indicators Sources
1 Social Norms SON1 At every meal, I usually don't leave a small amount behind SON2 I'm usually the one who takes the last bite New SON3 I usually share reducing food waste tips with my family/friends
DOE1 I usually finish food served by my family/friends New
DOE2 It is forbidden for me to throw away leftover food in my family
2020) DOE3 I was raised to believe that food should not be wasted
ENC1 I do think about the environment when I waste food (Blešić et al., 2021) ENC2 I do think about recycling the food waste generated
ENC3 I can eat leftovers from yesterday
ENC4 Wasting food would make me feel guilty about the environment
4 Time Pressure TIP1 I have enough time to avoid wasting food (Bhatti et al., 2023) TIP2 I try to finish my meal before I start working on anything else
Data gathering procedures
These stages will be followed to gather primary data from respondents as below:
The cornerstone of this research, the survey questionnaire, was meticulously constructed Drawing upon the foundation established by prior studies, the instrument was rigorously refined based on the invaluable guidance and recommendations provided by the advisor This meticulous process ensured the reliability and validity of the data collection tool
Following the development of the survey questionnaire, the researchers employed a convenience sampling approach to administer the instrument online This method involved soliciting responses from a readily available pool of participants.
Sample Size and Sample Techniques
Data was collected from February to March 2024, taking place after Chinese Lunar New Year event A web-based questionnaire in light of previous research was developed in both Vietnamese and English, regarding the lack of representatives and sampling bias in the method (Malhotra et al., 2020) Nonetheless, researchers normally selected to disseminate the questionnaire online (Aktas, Sahin, et al., 2018) for its convenience and low marginal cost (Schillewaert & Meulemeester, 2005) The participants took approximately 9 minutes on average to complete the online survey No incentive was offered in order to encourage complete responses
In order to mitigate the influence of socially desirable responding, the questionnaire introduction explicitly outlined the research objectives and assured participants of their anonymity Additionally, the survey design was meticulously crafted to minimize bias by employing a balanced use of positive and negative phrased questions (McCarthy & Liu, 2017; Von Kameke & Fischer, 2018)
A total of 290 participants completed the questionnaire The frequency of eating at home was used as a filtering tool that allowed for the exclusion of participants who negligently filled the form (n ) from the final data set, after which 278 usable responses became available for data analysis.
Data collection techniques
The purpose of data collection is to gather the information necessary to test research hypotheses derived from research questions These hypotheses are yet to be confirmed and require
18 empirical evidence, which is obtained through specific data collection methods Questionnaire is a common method for collecting data in research studies The researcher gathered primary data from either existing or former city dwellers in Vietnam through survey designed with two sections respectively:
Part 1: Contains detailed information of the respondents’ profile such as gender, age, marital status and education level (between high school and post-graduate scholars or other)
Part 2: Includes questions regarding customers’ awareness about food waste behavior The main content of this part is found on the basis of the Theory of Planned Behavior (TPB) presented in Chapter II
The researchers accumulate data and measure the perception of respondents using the Five points Likert’s Scale as described in the table below:
Table 7: Likert's Five Point Rating Scale (Adelson et al., 2010)
Rating scale Point ranges Verbal interpretation
Data Analysis Techniques
The data obtained from the questionnaires undergo coding, capturing and data cleaning Statistic Package for Social Science (SPSS) software version 22 and Partial Least Square (Smart PLS) version 4.0 are used for the data analysis The procedure of data analysis and the techniques used are elaborated as follow:
Descriptive statistics are defined by Lind, Marchal, and Wathen as "methods of organizing, summarizing, and presenting data in an informative way(A.Lind et al., 2005) The census and the weekly earnings of thousands of computer programmers are examples of large amounts of unorganized data However, there are statistical methods available to process this type of data in a meaningful way
This analysis can be done by presenting the processing of data collected from the responses to questions in the distributed questionnaire The results of data processing can be presented through tables, graphs, pie charts, graphics, and calculation methods such as median, average, and percentiles of data through calculation calculate averages, standard deviations and percentages This descriptive statistical analysis was applied to all three research models in this study
3.5.2 Reliability and Content Validity Analysis
Cronbach's alpha will be utilized in this test to evaluate the scale's overall consistency Its goal is to determine whether or not the measurement scales for each questionnaire item are consistent
A high level of dependability is indicated if the Cronbach's α value is higher than 0.7 When the Cronbach's α falls between 0.5 and 0.7, the internal consistency of the variable is deemed acceptable If the item's Cronbach's α coefficient is less than 0.35, it ought to be eliminated (Hair Jr et al., 2019)
Validity is the extent to which differences in observed scale scores reflect true differences among objects on the characteristic being measured, rather than systematic random errors (Malhotra, 2020) A validity test is conducted to ensure that the instrument is measuring what should be measured and that its accuracy is compared to the idea being measured The degree to which an empirical measurement represents a certain content domain (such as concepts and constructions) determines the content validity of the measurement This implies that objects must be built with the significance connected to each dimension in mind The validity and reliability analyses are applied to each of the three research models in this study
The Student's T-test and ANOVA test are terminology used to compare means Student's T-test examines two averages and determines whether or not they differ from one another If there are any significant variations between the demographic data (age and survey elements) and responses received from the consumers, the t-test was used to examine and clarify all the information To compare the means of more than two groups, the Analysis of Variance (ANOVA) is a more appropriate method than the T-test (Field, 2013) It estimates the difference between the average variance within groups and the corresponding amount of variance among group means (Kim, 2014) One-way ANOVA was used to examine and explain in more detail whether there are any noteworthy variations between the replies from responders and the demographic characteristic (experience)
Structural equation model (SEM) which is a technique that analyzes the relationships between multiple variables to evaluate hypotheses concerning their interactions and influences is one of the quantitative methods (Harrison & Friston, 2007)
Henseler, Ringle, and Sinkovics (2009) state that validity and reliability of reflective measurement models are critical factors to take into account For these kinds of evaluations, composite reliability (CR), an alternate internal consistency reliability metric, is applicable Higher numbers indicate more dependability The composite reliability ranges from 0 to 1 It's often understood to mean something like Cronbach's alpha In exploratory research, composite reliability values between 0.60 and 0.70 are often accepted, however in more advanced stages of study, values between 0.70 and 0.90 are regarded satisfactory Values above 0.95, however, are undesirable as they imply that all indicator variables measure the same thing and could not be reliable indicators of the construct On the other hand, a lack of internal consistency dependability is indicated by composite reliability scores less than 0.60
When evaluating validity, two commonly examined subtypes are convergent validity and discriminant validity Convergent validity refers to the extent to which a group of indicators represents a single underlying construct, which can be demonstrated by their unidimensionality Henseler et al (2009) proposed the use of average variance extracted (AVE) as a criterion for assessing convergent validity An AVE value of 0.5 or higher indicates satisfactory convergent validity, indicating that a latent variable can explain more than half of the average variance among its indicators
Substantial outer loadings on a construct indicate that the corresponding indicators share a significant amount of common variance, thereby capturing the essence of the construct This property is often referred to as indicator reliability As a general guideline, (standardized) outer loadings of 0.70 or higher are considered desirable Indicators with outer loadings ranging from 0.40 to 0.70 should be cautiously evaluated for potential removal from the scale, taking into account the impact on content validity In some cases, indicators with very low outer loadings may be retained to preserve content validity However, indicators with extremely low outer loadings (below 0.40) should always be excluded from the scale (Joseph F Hair, 2010)
Discriminant validity serves as a complementary notion to convergent validity It focuses on ensuring that two distinct concepts exhibit an adequate level of dissimilarity, indicating that the set of indicators for each concept is not expected to be unidimensional The Fornell-Larcker criterion is commonly employed to assess discriminant validity at the construct level In statistical terms, the Average Variance Extracted (AVE) for each latent variable should exceed the squared correlation between that latent variable and any other latent variable
To further examine and test the proposed relationships, Structural Equation Modeling (SEM) is employed
RESULT AND DISCUSSION
Descriptive analysis and mean comparison
Data used in this study was obtained from structured questionnaires designed which based on usable respondent consists of customers’ profile Table 8 presents the demographic frequency of characteristic of sample structure and general descriptions of respondents’ characteristics as following:
Source: Data processed by SPSS 22
Gender Based on result from table 1, there is a huge difference between women and men in respondent ratios, with women (61.9%) greatly outnumbering men (38.1%)
Age The largest age group was 18–24 (75.2%), followed by 25–50 (11.2%), Under 18 (10.8%), over 50 (2.9%)
Marital status A vast majority of research participants are single, accounting for 84.9% This percentage is over six times higher than that of married and other status combined (10.8% and 4.3%)
Education level Bachelor’s and Post-graduate dominate this demographic sampling, making up approximately 70% of survey respondents This figure springs from the convenience sampling method initiated by the researchers
Independent sample T test and One-way ANOVA are used to compare means between different demographic characteristics and customers’ responses
Source: Data processed by SPSS 22
Levene's Test for Equality of Variances in Table 10 indicates that the Sig value (0.512) is larger than 0.05, therefore the null hypothesis is not rejected It is implied from the table that there is no significant difference in food waste behavior between female (N2, M=3.5843, SD 0.79021) and male (N6, M=3.6724, SD=0.79000), Df'6, t=-0.441, p-value=0.659
Table 11: Analysis of Variance between Food Waste Behavior and Profile
Demographic Levene statistic Sig F-value p-value
Table 11 demonstrates that the p-value for respondent’s profile being Gender, Age, Marital status, and Education are all higher than they are required Thus, there is no significant difference among gender groups, age groups, marital status and education levels in food waste behavior.
Reliability Analysis
Table 12: Reliabilities among the variables
Cronbach’s α Lowest item – Total correlation
Highest Cronbach’s α if item deleted
Intention to reduce food waste (INT)
During the validation process, one item related to the intention to reduce food waste was excluded due to a low corrected item-total correlation (