Factors affecting green purchase behavior: a systematic literature review

The worldwide increased consumption of goods and services squeezes natural resources, thus causing severe damage to the environment. In the backdrop of the growing affirmative reaction of people, the inclination to buy green products is on the rise. Therefore, we explore the extant literature to identify the factors established for their role in determining the purchase of products having a less damaging impact on the environment. A systematic literature review was conducted following the Theory-Context-Characteristics-Methodology framework covering 151 empirical studies on green purchase intention and green purchase behavior, published between years 2000 and 2021. This paper identifies factors influencing consumers' green purchase intention and green purchase behavior and provides strategic insights to marketers to create better marketing opportunities for green products.

Although a considerable amount of literature has been published in the context of factors affecting green purchase behavior (GPB), research for exploring the specific factors that explain the attitude behavior gap is still lacking (Kumar et al., 2019;Panda et al., 2020;Prakash & Pathak, 2017).Also, studies are often inconsistent in their findings; e.g., Nguyen et al.'s (2017) and Sharma and Foropon's (2019) studies are conflicting on the effect of perceived behavioral control (PBC) on green purchase intention (GPI).Recent review-based studies exploring GPB and GPI are limited in terms of the number of researches used for review and the timespan of review.Further, Kotler (2011) and Sharma (2021 ) observed that green purchase tendencies are evolving.Therefore, an extensive review is essential to deeply understand green consumer behavior.The present study provides a systematic review of 151 extant literature relating to GPI and GPB published over the last 21 years and identifies a set of factors that may affect purchase intentions for green products.The study used the Theory-Context-Characteristics-Methodology (TCCM) review framework given by Paul and Rosado-Serrano (2019) to discover the new or less explored research domains that could explain GPI and GPB in terms of their theoretical and empirical aspects.
The attitude-behavior gap and lack of agreement on other consumer decision-making factors affecting green purchases have been noted as major global concerns and are receiving a lot of interest from industry and academia (Jaiswal & Kant, 2018;Sharma et al., 2021;Yadav & Pathak, 2017).The TCCM analysis provides new avenues for future studies (Rajan & Dhir, 2020) to help explore the specific avenues related to the marketing of green products.

| REVIEW STRUCTURE AND METHODOLOGY
We discussed about relevant studies, their search, and selection criteria in this section.

| Locating studies
We extracted 218 relevant research studies for systematic literature review (SLR) accessed through multiple sources (Figure 1) to ensure an extensive literature search over a long time period.

| Selection and evaluation
Following classic reviews (Billore & Anisimova, 2021;Chakma et al., 2021;Gilal et al., 2019;Hao et al., 2019;Khatoon & Rehman, 2021;Mishra et al., 2021;Paul & Benito, 2018;Paul & Mas, 2020;Paul & Rosado-Serrano, 2019;Rosado-Serrano et al., 2018;Södergren, 2021), the screening of articles was conducted.The screening criteria included studies investigating varied factors that affect consumer GPI and GPB.The paper selection criteria for SLR based on the journal impact factor, as suggested by Keupp and Gassmann (2009), resulted in the sourcing of high-quality papers with a yearly impact factor of at least 1.0.The high-impact factor journals were chosen for two reasons.First, researches published in these journals are likely to include ideas that are examined, more closely evaluated and extended in further studies.Second, these journals serve as scholarly evidence and significantly affect the field (Cheng et al., 2017;Podsakoff et al., 2005;Shabbir, 2020;Tahai & Meyer, 1999).Following Paul and Criado (2020), we eliminated 38 research papers for SLR published in journals with a lower or nonexistent impact factor.
Following SPAR-4-SLR protocol (Paul et al., 2021), this review is based on empirical studies examining various drivers, barriers, and other factors influencing consumers' GPI and GPB as they provide consumer insights across different cultures and contexts.
We read all 177 research papers to determine that the review excludes irrelevant studies.These research papers were further screened for their relevance, which led to the elimination of another 26 research papers and the use of 151 research papers for review purposes (Figure 2).a.We decided to choose the 2000-2021 period because the concept of green marketing gained new momentum after 2000 with advanced technology, rules and regulations by governments, and increased global environmental awareness levels (Peattie, 2001).Also, since 2000, researchers have extensively focused on more F I G U R E 1 Electronic sources used for paper extraction issues related to green products than previously considered (Chamorro et al., 2009), which is also evident in Figure 3. b.We used GPI, GPB, green products, sustainable consumption, eco-friendly products, and environmental consciousness as different keywords as search criteria to conduct relevant literature searches.Figure 4 shows GPI and GPB-related research gained momentum after 2015, and the research focus has shifted from GPB to GPI. c.The literature search identified 151 papers published in 75 journals accessed under the present study (Table S1).The sampled journals for review mostly have an impact factor of more than two and ensure the use of high-quality papers for review purposes.We observed a surge in research publication on GPI/GPB in top rating journals having a high impact factor.d.The psychographic variables consider the influence of subjective norms, attitude, values, perceived behavior control, moral norms, and other factors, which are more important for understanding green consumers, and instead of demographic variables, these are commonly used to profile consumer segments (Akehurst et al., 2012;Cornwell & Schwepker, 1995;Fishbein & Ajzen, 1975).Therefore, this review focuses on identifying psychological, social, and cultural factors affecting GPI and behavior and addresses the attitude-behavior inconsistency.consumers have become a driving force for companies to do their business by manufacturing green products, adopting different marketing strategies for promoting ecological purchase and consumption behavior, and creating an emerging global market (Akbar et al., 2014).

| GENERAL OVERVIEW
Purchase intention is a consumer's predisposition towards purchasing products (Yoo et al., 2000).GPI is an inner wish, an aspiration, and a motivation to buy products and services less detrimental to the environment (Mainieri et al., 1997).GPB involves actual purchasing and consuming products having less impact on the environment.
We synthesized the literature using the TCCM framework (Mansoor & Paul, 2021;Paul & Rosado-Serrano, 2019;Y. Chen et al., 2021) and identified the factors affecting GPI and behavior.The

| THEORIES
Table 1 shows the theoretical frameworks primarily used to explore GPB in the contexts like green packaging, food choice behavior, recycling behavior, green hotels, and organic food.Among 151 research studies, the maximum number of research papers used theory of planned behavior (TPB).Those frameworks explained GPI and GPB at cognitive, social-psychological, ethical, and moral levels with an underlying purpose of addressing attitude-behavior inconsistency.Various theories provide deeper insights and suggest the variables such as human values, ethics, innovativeness, and moral obligations.However, unless these theories are used in complementarity, we may fail to get a holistic understanding of key drivers of GPI and GPB.Norm activation theory (NAM), for example, is not successful in explaining the consumer's GPI while focusing on an individual's pro-environmental motivations and moral obligations (He & Zhan, 2018;Liu et al., 2012;Zhang et al., 2018).Integrating NAM with TPB provides a good estimation of pro-environmental behavior tendencies in the context of purchasing fair-trade goods, intake of organic meals, and recycling (Gatersleben et al., 2014;Park & Ha, 2014;Shi et al., 2020).

| Theory of reasoned action
Ttheory of reasoned action (TRA) is widely applied in prior studies to define the attitude-behavior relationship (Yii et al., 2020).Ajzen (1980) states that TRA predicts a person's intentions with certain positive beliefs, and such beliefs, in return, determine a person's attitude towards the behavior.Individual attitude is an essential factor which, along with subjective norms, determines behavioral intentions (Kotchen & Reiling, 2000;Masrom, 2007).

| Theory of planned behavior
TPB states that the more intent is towards a particular behavior, the more probable one is to engage in the desired behavior (Ajzen, 1991).
Consumer purchase intention is an essential tool for predicting consumer purchase behavior (Newberry et al., 2003).Using the TPB, various researchers confirmed the strong relationship between purchase intention and behavior (Ajzen & Fishbein, 2005;Lai & Cheng, 2016;Liobikiene et al., 2017;Minbashrazgah et al., 2017).Kanchanapibul et al. (2014) affirmed that green purchase intention often drives buying behavior due to human health and environmental reasons.

| Norm activation theory
NAM, developed by Schwartz (1997) with a perspective of altruistic behavior, emphasizes personal norms or a feeling of moral obligation, which is not the same as intentions.The awareness of performing or not performing defines personal norms derived from a particular behavior having consequences and the responsibility of performing a specific behavior (Schwartz, 1997).NAM has been used as a theoretical framework for predicting environment-friendly behavior (Ebreo et al., 2003;Harland et al., 2007;Matthies et al., 2012;Steg et al., 2014;Zhang et al., 2013).

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The Hunt-Vitell model Hunt and Vitell (1986) extended the Fishbein and Ajzen model and showed the connection between individual behavior and ethical beliefs.

| The consumption value theory
Consumption value theory (Sheth et al., 1991)

| Diffusion of innovations theory
Innovation is developing new ideas into marketable products (Schumpeter, 1939;Tidd, 1997).Zhen and Mansori (2012) used diffusion of innovation theory to explore consumers' intention and willingness to try organic food in different categories of the target audience and found that innovativeness might influence the consumer intention to purchase organic food.

| CONTEXT
A detailed synopsis of research papers focusing on GPI and GPB shows that these studies were conducted globally, and most studies examined GPB at a general level.Few studies have undertaken research at a particular industry and specific product level.The different industry and product categories covered by previous research are discussed next.

| Country
GPB research is found more popular among researchers in Western and Asian countries.Figure 7 shows that among 151 research studies, China accounted for the maximum number of studies (33), followed by the USA (21), India (20), and Malaysia (13).Other countries have less than ten studies, except Korea, Fiji, New Zealand, Saudi Arabia, Japan, and the United Arab Emirates, with one study each.

| CHARACTERISTICS
Attitude is the most researched variable in GPB's context.There are varied other factors suggested across various studies for their impact on GPI and GPB (Appendix S2, A 2.1 to A 2.4), which are discussed here as independent variables.The study identified these factors within the five categories, viz., cultural, individual, ethical, political, and product-related factors, with an idea to (i) bring coherence to their analysis, (ii) suggest the literature focus on explaining GPI and GPB, and (iii) find the gap areas for further investigation into interlinkages between factors originating in different categories which may have mediating or moderating relationships.Kluckhohn and Strodtbeck's (1961) framework suggests five value orientations: relationship, past-time, man-himself, man-nature, and personal activity for cross-cultural studies.Man-nature orientation, i.e., a man should not try to master nature and live in harmony, impacts GPI (Chan & Lau, 2000;Sreen et al., 2018).Extant studies gave initial insights into other cultural factors, including the doctrine of the mean and religiosity.The doctrine of the mean is a cultural thinking pattern derived from the traditional Confucian Philosophy of China (Yang, 2010) and impacts GPI and GPB (Sheng et al., 2019).Religiosity is a subcultural belief that consumers exhibit throughout their consumption choices (Wang & Wong, 2020).

| Political factors
Political action refers to a person's desire to engage in various socio-political issues such as lobbying political agents, participating in pressure groups, and boycotting irresponsible companies (Braithwaite, 1997).Political values such as individual politics and liberalism have a significant effect on GPB (Larson & Farac, 2019;Leonidou et al., 2015).The government role defined by the government's green initiative, including green product promotion among the citizens, manufacturers, and producers, influences GPI (Kumar et al., 2019).

| Product-related factors
Appendix S1, A 2.3.1, includes the product-related factors positively influencing GPI/GPB.These factors are acceptability, information about green products, functional values, green perceived risk, economic incentives, experience, green perceived value, eco-label, perceived product features and quality, green brand image, green perceived value, epistemic value, e-word of mouth, green consumption values, green advertising, eco-label, willingness to pay, marketing mix-4 P's, and novelty-seeking.Brand consciousness, product price, green products' availability, conditional value, green confusion, and perceived functional risk are the other product-related factors that negatively affect GPI/GBP (Appendix S1, A 2.3.2).The reported results for some product elated factors are, however, inconsistent.Willingness to pay factor impacts the willingness of consumers to purchase green products (Chaudhary & Bisai, 2018;Kumar et al., 2020;Narula & Desore, 2016), unlike Yadav and Pathak's (2017) research reporting no effect of WTP on GPI.For eco-labels, Farzin et al. (2020) report no relationship between eco-label and GPI due to a lack of consumer trust.Nilashi et al. (2019) and Lim et al. (2019) report the positive influence of eco-label on GPI.

| Research approach
Our analysis shows that quantitative approaches dominate the qualitative methods found in only seven sampled studies (Table 2).
One-hundred forty-eight quantitative studies used the primary data collection technique.Most of the studies collected cross-sectional data related to different age groups, income groups, gender, and educational backgrounds.Young consumers are the choice of many researchers, like Choi and Johnson (2019) and Kong et al. (2014).

| Analytical methods
The analysis of 151 pieces of research shows that, given their objectives, studies have used multiple tools and techniques on different types of data to improve the generalizability of the results and reduce common method variance (Table 2).The studies used factor analysis to identify factors affecting GPI and ANOVA to measure the impact of demographic characteristics on GPI.Descriptive analysis is done in seven studies, including Shahsavar et al. (2019) and Handique (2014).
For moderator and meditation analysis, Sheng et al. (2019), Lee (2017), andLing (2013) used hierarchical regression analysis in their studies.Other studies used process macro given by Andrew F. Hayes.Yue et al. (2020) and Straughan and Roberts (2000) are among the thirteen researchers who used correlation analysis.Path analysis is used less commonly and found in two select studies, i.e., Ekawati et al. (2020) and Sharma and Foropon (2019).Basgoze and Tektas (2012) and Carrigan and Ahmad (2001), among others, used qualitative research analysis like semi-structured in-depth interviews, focus group discussions and Kohonen's LVQ behavior prediction agent for analyzing the purpose of GPI and GPB.

| FUTURE RESEARCH DIRECTIONS
Environmentalism is a vital aspect of sustainability, resulting in increased environmental concern among consumers and raising the demand for green products worldwide (Akbar et al., 2014).Various studies have confirmed the gap between attitude and behavior (Ackermann & Palmer, 2014;Iweala et al., 2019;Zhou et al., 2013) and provide very little quantitative evidence on the intention-behavior gap (Hassan et al., 2016).Following Paul and Barari (2022), TCCM framework (Paul & Rosado-Serrano, 2019) used to outline future research directions based on theory, context, characteristics, and methodology.

| Theories
The past studies used the TPB and the TRA, affirming that GPI predicts consumers' purchase behavior.The studies reporting attitudebehavior inconsistency modified TPB and added various NAM model constructs to explain reasons for attitude-behavior inconsistencies in green purchasing (Shi et al., 2020;Gatersleben et al., 2014;Park & Ha, 2014).
As an outcome, we need new theories, methods, and paradigms to carry research studies in the post-pandemic era to analyze the new processes, patterns and problems.Following prior models (Paul & Mas, 2020), we call for developing frameworks and models in the same way to carry out future studies in this area.demand and attitude for green products are expected to vary across different cultures (Ottman, 1998;Peattie, 1995).A comparative analysis between Asian and Western countries may help understand consumer preferences for green products across these countries.
Industry-level analysis shows that GPB-related studies are in different industries such as food, apparel, automobile, construction, electrical equipment, hotel, manufacturing, and retail.Future research on specific industries and products must clarify their green initiatives and how they influence and encourage consumers to go green.
Further, consumers' perceptions of companies' sustainability practices play a vital role in significantly influencing consumers' attitudes, intentions, and behavior (Feldman & Vasquez-Parraga, 2013;Rios et al., 2006;Stolz et al., 2013).A business can become sustainable through its managerial practices and decision-making abilities and can grow with the help of consumer support (Schaltegger & Burritt, 2018).

| Characteristics
The study shows that green consumer behavior is not simply affected Past researchers used different approaches to identify various factors affecting consumers' attitudes and behavior towards green products in different contexts.The factors with significant effect thus help marketers segment the market and maximize GPB.A comprehensive chart F I G U R E 2 Flow chart for selection of relevant studies F I G U R E 3 Number of research publications (Figure 5) shows theories and concepts related to GPB research at the theoretical or empirical level.Accordingly, we have researched various stages, including adoption, execution, and outcomes.The theoretical level covers theories that highlight the conceptual frameworks checked empirically and varies in terms of the unit of analysis.Our research shows that past studies examined various associated concepts and outcomes at the consumer, product, industry, and country levels and covered the related characteristics such as demographics, industry type, and product type.We analyzed these levels to explain behavioral intentions for green products.Regarding outcomes, green F I G U R E 5 General overview of GPB and GPI studies F I G U R E 4 Number of GPI and GPB-related research studies paper identifies factors affecting GPI and behavior based on analysis and synthesis of extant literature.Apart from the psychological factors under the individual category, the study could identify cultural, ethical, political and product-related factors affecting GPI and GPB.It is observed that consumer characteristics such as socio-demographics and personality traits positively influence GPB in varied cultural contexts of Western and Asian countries.Further, Effendi (2020) and Yu and Lee (2019) suggest similarities and dissimilarities in GPB at the industry level.Prior studies show how the factors like green lifestyle, willingness to pay (WTP), and health consciousness determine their GPB.
suggests social, functional, epistemic, conditional, and emotional values that affect consumer choice behavior.Consumption value as the basis of a successful transaction persuades consumers to buy repeatedly(Yeh et al., 2021), and consumers hold a good attitude towards green products and feel that they get emotional benefits from them(Adhitiya & Astuti, 2019).4.7 | Cognition-affect-behaviorUsing the Cognition-affect-behavior (C-A-B) model, Nguyen et al. (2019) study shows the mediating effect of green skepticism on the negative relationship of greenwash with GPI.Acceleration of greenwashing actions in the food industry influences consumers' cognitive knowledge, and the suspicion of green food claims affects their GPI.4.8 | Values-lifestyle-behavior hierarchy Homer and Kahle (1988) suggested the hierarchy of abstract values, individual attitudes, and specific behaviors in a particular situation.It shows how one's value perception manipulates one's actual behavior through the attitudinal construct (al Mamun et al., 2018; Milfont et al., 2010).4.9 | Choice-behavior model Sheppard et al.'s (1988) choice-behavior model indicates that behavior affects intention formation.Based on the choice-behavior model, Chen et al. (2018) confirmed that cognitive and affective aspects have a significant impact on consumer purchase intention for green appliances.
Five studies the retail and seven on the electrical equipment industry focused on energy-saving appliances and FMCG goods (e.g.,Chen et al., 2021;Tascioglu et al., 2017;Waris & Hameed, 2020).Six studies related to the hotel industry are focused on hotels and restaurants.Eight studies about the apparel industry focused on apparel products and sustainable clothing (e.g.,Jung et al., 2020; Mai Nguyen, 2019; Theresa Rausch & Kopplin, 2020; Wang   et al., 2020).The automobile industry accounts for five studies, likeHamzah and Tanwir (2020) andLim et al. (2019), which focused on electric and hybrid vehicles.Three studies related to the construction industry focus on green housing(Chen et al., 2021;Kumar et al., 2020;Zahan et al., 2020).
Culture, personality, political, and ethical values are additional factors determining one's pro-environmental attitudes towards green products to help identify an environmentally-conscious consumer.Other theoretical aspects like Hunt-Vitell model (ethical beliefs), values-attitudes-behaviors (perception of value), choice behavior model (the process of forming intention), diffusion of innovations theory (consumers' willingness to try), and the cognitionaffect-behavior (cognitive and affective attributes) bring clarity on green attitude-behavior gap.However, less attention has been paid to the theoretical base explaining the inconsistency in the conduct of individuals when it comes to GPI and behavior.
by attitude but also by cultural, personal, political, psychographic, and ethical values.Factors such as environmental attitude, environmental concern, perceived behavior control, environmental knowledge, subjective norm, perceived consumer effectiveness, and collectivism appeared to be the most studied variables impacting GPB.Political and ethical factors also draw researchers' attention and confirm a significant relationship with GPB.Product-related variables such as price, features, availability of green products, inconvenience in purchasing the product, brand image, and green advertising are the significant barriers to consumer's GPB and affect converting positive attitudes into actual actions.Various studies contradict their results, leading to inconsistent research findings.Appendix S2 (A2.1 to A2.4) lists the factors influencing GPI and GPB, where many factors having a few citations need to be investigated further for their role in a specific context.8.4 | MethodologyThe dominant methods used for research on GPI and GPB are quantitative, including structural equation modeling (SEM), regression, and factor analysis.Researchers primarily used a primary survey with a focus on young consumers.Targeting other age groups for future research may, thus, help in addressing age biases in prior studies.We suggest using qualitative research tools with pure or mixed-method research design to better understand consumers' GPB.Developing a GPB scale with the help of CFA and EFA is also a possible direction for future research.This study has certain limitations.First, the present review has not explored the impact of identified factors on individuals from different cultural and social backgrounds.Second, the current review does not include the studies related to demographic characteristics for the reasons specified earlier in this study.These factors could provide further insights into the identification of consumer segments holding GPI and behavior.Third, only a few keywords are used for literature search, whereas adding other keywords could expand it for future studies.Future studies may focus on exploring other factors to bring more clarity to inconsistency in GPB.To provide deeper insights on GPB, future researchers can empirically examine the effect of overlooked variables studied less in prior studies in the context of GPI and behavior.
Theories employed in GPI and GPB (N = 151) 4.3 | Value orientation modelValue tells people what is reasonable, necessary, valuable, desirable, and appropriate for them.The value orientation model