Scale Development of Sustainable Consumption of Clothing Products

Researchers and companies are paying attention to consumers’ sustainable consumption of clothing products. Clothing industry and fashion consumers have been criticized for a long time due to endless mass production and overconsumption. Despite the efforts of corporations to use sustainability as a marketing tool and an expanding literature exploring consumers’ response to such marketing, the definition of sustainable consumption of clothing products (SCCP) remains unclear. Academic works lack comprehensive discussions regarding SCCP in the perspective of consumers’ awareness and behavior. Furthermore, no widely accepted measurement tool of this concept exists. The validated measurement instrument will eventually help the diagnosing of the mental and behavior status of clothing consumers’ SCCP and further support to establish consumer guidance aimed at resolving sustainability issues related clothing consumption. This study aimed to conceptualize, develop and validate a scale to measure SCCP from the perspective of general clothing consumers. Literature review and interview were used to collect qualitative data for scale item generation. Then, surveys were conducted two times to acquire quantitative data from respondents to purify and validate the scale items. Content analysis, exploratory factor analysis and confirmatory factor analysis using MPlus were used to explore and predict the data. Based on reliability and validity check, the results are apparent that the scale shows good psychometric properties.


Introduction
Sustainability regarding production and consumption is a hot topic in various industrial sectors. In the clothing industry, sustainability issues related to the production and consumption of clothing products are also drawing attention. The problems of unsustainability related to clothing products exist typically in the production process of clothing fabrics and textiles harming the ecological environment and they include labor issues of sewing workers in developing countries and the increase of the size of nonbiodegradable clothing waste. These issues are mainly understood as a duty of clothing companies, with examples of the industry leaders taking efforts in various ways to improve sustainability issues, developing and using eco-friendly materials, disclosing labor-related information, recycling and upcycling or taking new business models that prevent clothing wastes. On the other hand, academia in clothing studies has been conducting various studies on sustainable consumption of clothing products (SCCP) from the consumers' perspective. However, in many studies, when it comes to assessing how consumers are aware of SCCP and how they actually involve in clothing consumption behavior, it was mainly focused on measuring the purchase intention of sustainable clothing products or services offered by the industry [1][2][3][4][5][6][7]. The purchase is merely a partial behavior of the whole consumption process, while the actual consumption stages are more complex including consumer awareness and behavior in various domains and consumption stages. Thus, there is a lack of research on the systematic consideration to measure the comprehensive concept of SCCP. In particular, scholars and practitioners are still uncertain when it comes to which domains and activities should be defined as measuring tool for SCCP. Then, in order to resolve these uncertainties, it is required to take conceptual approaches and reveal a measurement instrument. The purpose of this study is to develop and validate a scale on SCCP.
The necessity of developing the scale of SCCP stems from several reasons. First, sustainable consumption is an ambiguous concept itself. Sustainable consumption has not been conceptualized from in-depth discussions or conceptual exploration of it, but, is based on the concept of "sustainable development", making it difficult to present clear definitions or concepts as they consist of incidental consumer practices. Sustainable consumption studies show a variety of definitions in each study [8] and it is considered difficult to present a universal definition of sustainable consumption that can be used in a multidisciplinary way [9]. In the same vein, the concept of SCCP is also unclear. It has been presented by researchers with respective definitions, being too general and difficult to measure.
Second, SCCP was mostly measured by the intention of purchasing certain sustainable clothing products, limiting the role of consumers simply as "purchasers" [1][2][3][4][5][6][7] and overlooking the conceptual multidimensionality inherent in SCCP. When it comes to general green consumption, scholars have discussed various pro-environmental behaviors such as use, recycling, reuse, rental etc. [10][11][12][13][14]. Nonetheless, there is a lack of discussion on the impact of the use and disposal stages of "clothing products". A comprehensive perspective of understanding consumer awareness and behavior in a sustainable clothing lifestyle is needed. Consumption includes the post-purchase stages such as use and disposal and consumers could refuse or refrain making purchases or make better choices than purchasing new merchandise. Therefore, dealing solely with "purchase" when measuring sustainable consumption behavior lacks understanding of various roles of consumers. In particular, recent consumers show a tendency of making consumption based on their values [15]. Collective consumption, boycotting and anti-consumerism were also notable [16][17][18]. Nevertheless, simply purchasing eco-friendly or ethical clothing products has been simply applied when measuring SCCP [19,20], other consumer behaviors than the purchasing stage have been neglected. Further discussion could be conducted about the impact of decreasing the size of consumption and behaving in the use, care and disposal of clothing products and anti-consumption movement. It is necessary to consider multidimensionality from the perspective that SCCP is not just a single entity or phenomenon. The consumer should be understood as an active entity with multifaceted roles.
Third, sustainability issues of clothing products relate not only to the ecological aspect, but also to the social, ethical and cultural aspects. The previous studies under the topic of SCCP have heavily focused on the ecological aspects such as recycling, upcycling and consumption of eco-friendly clothing products [21][22][23]. Unlike other products, however, clothing products involve many other sustainability aspects besides ecological impacts. The characteristics of clothing products consumption include self-expression, aesthetics and functionality; thus, there is a wide range of related issues under ethical and cultural aspects. For example, consumers may express their support for beliefs or political opinions by adopting specific clothing design, color or brands that match their values. Furthermore, clothing products are understood as value-added products and there exist various attitudes about ethical perceptions towards design copyrights. In addition, the structural change in the clothing industry has raised the issue of the labor environment of sewing workers as manufacturing countries move to developing countries. Further, the issue of ethics in the use of animal fur in clothing is also a subject that has drawn constant attention. As such, the consumption of clothing products leads to in-depth discussions in terms of labor, animal, ethics and culture [24]. It is necessary to reflect these issues in many different aspects in conceptualizing SCCP and developing measurement tools. In other words, these aspects need to be expanded in regards of measuring SCCP.
One earlier article in the Sustainability journal has presented scale development study of sustainable consumption; Quoquab and Mohammad found cognitive, affective and conative domains of sustainable consumption [25]. Theory of mind (ToM) was used as their theoretical background, which enables understanding of individuals' awareness, knowledge, convictions and preferences [26]. Quoquab and Mohammad pointed out previous scales of sustainable consumption are limited in a behavioral perspective. Then, their finalized scale of sustainable consumption was validated as multi-dimensional constructs of three domains (cognitive, affective and conative). In this study, we also suggested SCCP as multi-dimensional constructs. The result shows the developed SCCP scale has multi-dimensions: awareness (knowledge and belief) and behavior (conative behavior and preference).

Sustainable Consumption and Consumer Awareness
Awareness is understood as a major prerequisite for behavioral intention of sustainable consumption. Roth [27] presented environmental literacy, of which environmental awareness is defined as individuals and social groups being aware of the environment and related issues. Arcury [28] defined environmental awareness as knowledge and information about the environment and nature and their impact on human behavior. In other words, awareness is about recognizing problems and related information about the subject and reacting sensitively to the subject based on understanding. The measurement of environmental awareness made by Littledyke [29] was in combination with cognitive and emotional aspects. Bergman [30] suggested awareness of environmental problems, the need recognition of improvement and cognitive environmental sensitivity as measuring dimensions of environmental awareness. Awareness is a process of accepting and internalizing external information, which has been measured in various variables depending on the type of information. Awareness places more weight on the perception of the acceptor than on the level of knowledge of objective information [31]. This is the perception and internalization of information about the environment by the acceptor, focusing not on objective judgment of the information, but on how the respondent understands and feels the information, including subjectivity. Therefore, it is reasonable to judge how consumers perceive the information internally in the measurement, rather than just looking at the level of knowledge of independent information that is remote from consumers.
Awareness is usually understood as a multi-dimensional concept and sub-dimensions frequently mentioned include knowledge, belief, attitude, value and so on [32]. Specifically, awareness in this study suggests that responses should be measured on the basis of how much respondents perceive themselves to be aware of the problems and coping strategies related to SCCP and how much they are confident that they can benefit from SCCP. That is, the awareness dimension consists of knowledge and personal belief related to SCCP. Early researches on SCCP discussed on strategies to prevent overconsumption or misconsumption at the purchasing stage [1][2][3][4][5][6][7] or to extend the life cycle of clothing products at the use stage [33] and on reuse or recycle of clothing products at the disposal stage [34]. Since suitability is an umbrella concept, it covers environmental and societal issues on various perspectives: eco-friendly clothing consumption [35], ethical clothing consumption [36], creative clothing consumption to reduce frequent clothing purchases [37], boycott of products from unethical clothing companies [38] and slow clothing consumption against fast fashion with faster production and consumption cycles [39]. According to the suggestion of Schahn and Holzer [40], knowledge was distinguished into abstract and specific domain. Following the distinction of knowledge, SCCP knowledge can be divided in to abstract domain (knowledge about causes of unsustainability in environmental and social aspects related to clothing industry) and specific domain (knowledge of coping strategies of consumers on the stage of purchase, use and disposal during clothing consumption).
In pro-environmental behavior literature, Stern's environmentally significant behavior is widely accepted to get understanding of determinants and types of pro-environmental behavior [41]. Stern summarized previous researches conducted in environmentalism field and developed a conceptual framework of factors determining environmentally significant behaviors [41]. According to Stern's proposal, value -belief -norm (VBN) theory, has been used to explain the determinants of environmentalism. The individual's value, including altruistic value and personal belief and norms, are determinants of proenvironmental behavior. This causal chain is supported by substantial evidence from previous work [42][43][44][45]. In a nutshell, referring the concept of environmental awareness by Roth [27] and the conceptual framework by Stern [41], we propose that awareness of SCCP consists of knowledge and belief (a degree of how much an individual believes in the positive consequences of participating in SCCP) ( Figure 1). Cognitive and affective domains of sustainable consumption scale in the earlier study implied knowledge, personal belief and feelings about the sustainable consumption [25]. As opposed to sustainable consumption in general goods, SCCP is a less accepted concept for general consumers and less institutionalized. Thus, assessing the varying knowledge and various beliefs about SCCP is necessary when measuring it.

Sustainable Consumption and Consumer Behavior
Referring to the environmentally significant behavior theory by Stern [41], the definitions of environmentally significant behavior have two meanings: impact-oriented and intent-oriented behaviors. As stated by Stern [41] (p. 408): Both definitions of environmentally significant behavior are important for research but for different purposes. It is necessary to adopt an impact-oriented definition to identify and target behaviors that can make a large difference to the environment. This focus is critical for making research useful. It is necessary to adopt an intent-oriented definition that focuses on people's beliefs, motives and so forth in order to understand and change the target behaviors.
In this study, we applied both definitions of sustainable consumption behaviorimpact-oriented and intent-oriented behaviors-considering the specificities of clothing products. We conceptualized SCCP behavior in our scale to measure both consumption habits and behavioral intentions based on self-reports. Previously, studies in SCCP discussed various SCCP behavior by exploratory studies with qualitative approach. Results presented using secondhand clothing, buying vintage clothing and adopting clothing rental services are significant behaviors to resolve the unsustainability of clothing consumption [46][47][48][49]. Although those behaviors are derived from different motives, the consequences of using secondhand, vintage and rental clearly contribute to avoiding waste resources, disconnecting the cycle of overconsuming of brand-new clothing products. From the viewpoint of impact-oriented behavior, avoiding overconsumption is understood as one of possible solutions to resolve unsustainability problems. Buying fewer clothing products also comes from the different motives (e.g., financial, personal values, low interest in fashion, etc.), but is an evident way to reduce ecological and industrial concerns [50]. While buying less and using secondhand, vintage and rental seem to be mere individual preferences about clothing consumption; however, they are SCCP behaviors, from the perspective of impact-oriented behavior.
Regarding intent-oriented behavior, this can be divided into public and private spheres according to Stern's proposal [41]. Unlike previous studies focused on revealing the determinants of environmental behavior, Stern tried classifying the types of environmental behavior according to the strength of influential impact, under public and private spheres. Behavior in the private sphere means personal actions taken routinely, such as waste sorting, recycling and purchasing of eco-friendly products, which produce direct contributions to environmentalism. Behavior in public sphere means collective actions of consumer activism and political involvement. There are examples of collective action such as protecting consumer rights, demanding corporate responsibility for products, campaigning anticonsumption, protesting against some brands and businesses, writing articles, etc. [51]. This lies in the same vein with the concept of sustainable citizenship [52], where the impact is indirect, but the level of involvement is very high. SCCP activism is thought of as an important variable.
Conative behaviors in private sphere include mindful consumption and specific consumer actions in line with consumption stages (purchase-use-disposal). Mindful consumption is an emerging topic in the field of sustainable consumption [26,53]. The definition of mindfulness is "inherently a state of consciousness" [54]. Mindful consumption means the state of individuals being aware of their choices underlying consumption. Researchers argued that the mindful consumption leads to sustainable consumption since when consumers are more mindful, consumers can be aware of their consumption habits and internally process information about the impact of consumption [55,56]. Quoquab and Mohammad suggested the cognitive domain of their scale of sustainable consumption as a mental state being aware of sustainability issue and caring the consequences of their consumption referring from mindful consumption literature [25]. Thus, along with conative consumption behaviors at the stage of purchase, use and disposal, the mindful consumption of SCCP is also measured as significant behavior.
The behavior dimension of SCCP in this study consists of two dimensions: intentoriented and impact-oriented. Impact-oriented behaviors of SCCP are the behaviors that (1) refrain the overall consumption, (2) avoid purchase of a new clothing merchandise by using secondhand, vintage or rental services. Intent-oriented behaviors mean (1) consumers' consideration of sustainability (mindful consumption), (2) purchasing sustainable products, (3) taking sustainable actions during use and disposal and (4) sharing information and mutual support through online or offline communities (SCCP activism) ( Figure 2).

Definition and Dimensionality of the SCCP Construct
In this study, SCCP has two aspects: the awareness and the behavior. The awareness of SCCP has four knowledge, one belief factors referring to awareness1 (PEIC = perceived environmental impact of clothing products), awareness2 (PSIC = perceived social impact of clothing products), awareness3 (KSP = knowledge about sustainable purchase of clothing products), awareness4 (KSUD = knowledge about sustainable use and disposal of clothing) and awareness5 (BSC = belief toward sustainable consumption of clothing products).
The behavior domain of the SCCP consists of four intent-oriented and two impactoriented behaviors: behavior1 (MCB = mindful consumption behavior of clothing products), behavior2 (SPB = sustainable purchase behavior of clothing products), behavior3 (SUDB = sustainable use and disposal behavior of clothing products), behavior4 (AB = activism behavior of SCCP), behavior5 (BL = buying less) and behavior6 (SVR = secondhand, vintage and rental).
PEIC means the degree of an individual being aware of ecological problems caused by clothing consumption. PSIC refers to understanding of social and cultural problems within clothing consumption. KSP means the level of knowledge when choosing sustainable clothing products at the stage of purchase. KSUD is about how much an individual knows how to lengthen the product life span during use and disposal. BSC refers the degree of how much an individual believes in the possible positive outcome in participating in SCCP.
MCB means the degree of how much an individual considers and cares the importance of SCCP. SPB refers to whether sustainable clothing products are actually purchased or not. SUDB measures how an individual acts sustainable behavior at the stages of usage and disposal. AB means whether an individual involves in activism related to SCCP. BL is to reduce waste by purchasing less products. SVR is to buy secondhand or vintage products and to use rental services without purchasing brand-new products.

Research Methodology
Scale development procedures are well established by Churchill [57], DeVellis [58] and Netemeyer et al. [59]. Following the guidelines from the research above, the processes of this study consisted of five stages as below ( Figure 3). According to Churchill [57], scale development is the procedure of, specification of a range of constructs, extraction of initial items, data collection, item purification, new data collection and evaluation of reliability and validity, in order. Considering the suggestion above, firstly construct and initial items was derived through literature review and then items were supplemented through consumer interviews to fulfill the things that had been overlooked from precedent studies or for contents to be applied to keep pace with recent consumer changes. Then, five researchers in the field of clothing consumption studies participated in initial item purification. All selected researchers were well aware of the unique characteristics of clothing consumption.
Besides, the study aimed to identify the reliability and validity and present the final scale by validating the applicability of the scale items. Thus, surveys were conducted a total of two times. In the first survey, item purification was conducted until the time when the optimal factor structure was acquired while repeatedly deleting items which harmed the uni-dimensionality through the exploratory factor analysis. In the second survey sample, verification by the confirmatory factor analysis was conducted to check if the factor structure confirmed in the first sample was valid for a new sample. Furthermore, second-order factor analysis was conducted to determine whether the first-order constructs are reflections of the higher order construct (SCCP awareness or SCCP behavior). Finally, nomological validity was checked on the purpose of verifying the predictability of the newly developed constructs.

Scale Item Generation and Initial Purification
Firstly, SCCP was structured through the literature review and initial items were derived. Hereafter, insights derived from in-depth consumer interviews were made into supplementing items and then, items were corrected and rephrased through an interview with five experts. The selection of participants for consumer interviews was by purposive sampling. Subjects adequate for research aims were selected as a sample under judgment by the researcher. Sampling was completed when the researcher thought that the number of research participants reached saturation for collecting enough data considering the suggestion by Strauss and Corbin [60].
The qualification for interviewees was set as "consumers who have knowledge and experience in the sustainable consumption of clothing products". Those who considered themselves as ones meeting the condition were adopted as interviewees. A total of 23 persons finally participated in an interview. An in-depth interview was conducted for about a week in January 2020 after obtaining the approval for research by the University Review Board. All of interview details were recorded and transcribed and participants were informed of it and gave their consent. During the interview, detailed explanations about sustainable clothing consumption were not provided and participants were given a rough definition on the concept. Open-ended questions were asked in order for them to freely express what they thought. The example of questions asked are: "what comes to your mind when you think of sustainable clothing consumption?", "how much do you know about sustainability issues regarding clothing consumption?", "how do you participate in sustainable consumption of clothing products?" and "why is sustainable clothing consumption important to you?" Participants were encouraged to fully describe their experiences and opinions through semi-structured interviews. Additional questions were given to them if reconfirmation of a comment was necessary. It took about 26-74 min per person.
The deductive approach of item generation was taken in this study [61]. Unlike inductive approach of item generation, we generated initial items first based on the extensive analysis of the literature, then supplemented items from the interviews. The insights from the content analysis of interviews were related to respondents' ability to distinguish the environmental impact from raw materials and dyeing or finishing (PEIC1-2), knowledge about animal rights and alternatives while consuming clothing made of fur and feather (PSIC 2), various aspects of belief about consequences of SCCP (BSC) and many different ways in participating in SCCP activism (AB). After initial items derived, they were revised reflecting opinions by five clothing researchers (two Ph.D. researchers and three Ph.D. students). In results, some items were dropped and rephrased verifying content validity and face validity.

Scale Item Purification
With regards quantitative research design, the target number of samples was set as more than 300 individuals because of a statistical suggestion that a sample size of over 300 is desirable when conducting exploratory factor analysis to develop a scale with a limited range of an item score (1-7) Likert response form [62]. Based on the results of the exploratory factor analysis on initial items, the research made an attempt at purifying preliminary items on the scale for SCCP. Korean male and female consumers in their 20s-30s participated as survey respondents. The data were collected via quota sampling with the same ratio for gender and age. The survey was based on online panels of a research company and it began in April 2020. A total of 320 responses were used for the analysis. As for the demographic characteristics of the sample, there was a similar ratio between males and females and between age groups (male: 49.1%, female: 50.9%; 20s: 48.8%, 30s: 51.2%). As for education, university graduates or higher showed the highest ratio as 64.4%, followed by undergraduates as 20.3%, graduate students as 10.9% and high school graduates or under as 4.4%. As for marital status, those unmarried occupied 74.4% and those married accounted for 25.6%. In the case of monthly average household income, 5 million won (USD $4500) or more occupied the highest as 30.3%, followed by amounts between 3-4 million won (USD $2700-3600) as 21.9%, those between 2-3 million won (USD $1800-2700) as 20.6%. Furthermore, there were those between 1-2 million won (USD $900-1800) as 11.3%, those between 4-5 million (USD S3600-4500) won as 10.9% and those less than 1 million won (USD $900) as 5.0%.
Uni-dimensionality was confirmed and purified for the samples of 320 persons through the exploratory factor analysis and items of cross loading (significantly showing a loading value of more than 20 from two or more factors) or items with a factor loading lower than 20 were settled to be deleted. As a tool for the exploratory factor analysis, Mplus 8.4 was used. Common factor analysis was conducted through Geomin oblique rotation. The final factor structure was decided through the comparison of goodness of fit (comparative fit index (CFI), Tucker-Lewis index (TLI), the root mean square error of approximation (RMSEA), and standardized root mean square residual (SRMR)) and interpretability for the factor model within each dimension. In this study, the exploratory factor analysis was implemented under the awareness and behavior dimensions. Then, analyses on the reliability and correlation among each factor were conducted to judge the adequacy of factors. Cronbach Alpha and correlation coefficient values were calculated using SPSS 23.0. Through the comparison of factor loadings, correlation coefficients and average variance extract (AVE) derived from the factor analysis, the research verified convergent validity and discriminant validity.

Scale Item Validation
The second test was conducted and analyzed to validate the scale by identifying if results of the exploratory factor analysis from the first test were acceptable for a new sample. Goodness of fit and factor loading values were analyzed by the confirmatory factor analysis based on data collected for 352 participants. The second test aimed to secure the external validity by validating the factor structure of five awareness and six behavior factors through confirmatory factor analysis and second order factory analysis. An online survey was conducted. Responses collected from 352 participants were used for the analysis. Data were collected for three days about at the end of April 2020. As for the demographic characteristics of the second survey sample, a ratio between males and females and between age groups was allocated to about 50% each. As for education, university graduates or higher showed the highest ratio as 63.9%, followed by undergraduates as 15.9%, graduate students as 11.1% and high school graduates or under as 9.1%. As for marital status, the unmarried occupied 73.6% and the married accounted for 26.4%. In case of monthly average household income, amounts between 2-3 million won (USD $1800-2700) occupied the highest as 47.4%, 5 million won (USD $4500) or more as 22.4% and amounts between 1-2 million won (US $900-1800) as 18.5%, showing a similar figure. The validation of the second survey data was conducted through re-verification of the purified scale items. Mplus 8.4 program was used for confirmatory factor analysis and second order factor analysis and SPSS 23.0 for the reliability analysis.

Item Purification Results
As for goodness of fit, in case of CFI, TLI more than 0.90, a model is evaluated as the one with a good fit and it is assumed to be corrected in case of less than 0.80 [63]. RMSEA, SRMR values of 0.05 or less are regarded to be very adequate but it can be accepted in case of 0.08 or less [64]. Goodness of fit was firstly identified and in case of 28 awareness items for five factors, CFI = 0.948, TLI = 0.921, RMSEA = 0.063, SRMR = 0.028 and in the case of 34 behavior items for six factors, CFI = 0.923, TLI = 0.883, RMSEA = 0.072, SRMR = 0.030. Therefore, they satisfied criteria for goodness of fit and the number of factors was decided. Scale items were purified relying on the values of factor loading. As a result of the exploratory factor analysis, in general when factor loading exceeds 0.50, it is interpreted as a key variable, but in case of oblique rotation, an item more than 0.20 is interpreted significantly [65]. Hence, whether to delete an item or not was decided considering construct dimensionality, rather than a simple number. In addition, a relation with other factors was to be considered in a comprehensive manner, since it was obtained from oblique rotation. In order to maintain uni-dimensionality, the research considered deletion in case of cross loading where more than two factors have statistically significant loading of 0.20 or more at the same time [65]. In addition to a case where more than two factors show significant factor loading over 0.20, it is said as cross loading when both factors have 0.10 or less loading difference. In those cases, the study considered deletion for uni-dimensionality.
Finally, in scale purification through the exploratory factor analysis (n = 320), six awareness items and four behavior items were deleted. After the purification, 52 items remained, including 22 for awareness and 30 for behavior. Tables 1 and 2, below, show items of each dimension after item purification and the results of the exploratory factor analysis. They were prepared based on a matrix value by Geomin oblique rotation and p < 0.05 was found for every factor loading after rotation. Every Cronbach alpha value was more than 0.70, showing the internal consistency. In general, a research confirms the convergent validity by the factor loading of each item more than 0.70 (at least more than 0.40). In this study, one item (SUBD7) showed factor loading slightly under 0.400, but still, the item was not removed for its contents. According to Fabrigar et al., lower factor loadings sometimes appear, considering the characteristics of behavioral science in the process of scale generation, but still the item is acceptable upon the researcher's judgement [66]. Discriminant validity was confirmed by meeting the criterion of Fornell-Larcker (discriminant validity is guaranteed when square root of AVE is larger than a value of correlation coefficients among the rest of latent variables) [67]. Tables 3 and 4 show data about discriminant validity  Numbers in diagonal line are the square root of average variance extracted estimates (AVEs). Others represent correlations between latent variables, which are significant at p < 0.001 level. PEIC = perceived environmental impact of clothing products; PSIC = perceived social impact of clothing products; KSP = knowledge about sustainable purchase of clothing products; KSUD = knowledge about sustainable use and disposal of clothing products; BSC = belief toward sustainable consumption of clothing products. Numbers in diagonal line are the square root of average variance extracted estimates (AVEs). Others represent correlations between latent variables, which are significant at p < 0.001 level. MCB = mindful consumption behavior of clothing products; SPB = sustainable purchase behavior of clothing products; SUDB = sustainable use and disposal behavior of clothing products; AB = activism behavior of SCCP; BL = buying Less; SVR = secondhand, vintage and rental.  Figures A1 and A2 (Appendix A). Furthermore, factor loadings of each item were more than 0.40; therefore, convergent validity was confirmed. In other words, proper fit and factor values of the structure and items were derived in the item validation stage with new sample. Thus, 22 items of five awareness dimensions and 30 items of six behavior dimensions-except for items deleted in the item purification process in the first sample-were appeared as valid. Therefore, the final scale was fixed as same as the model and items represented after the item purification stage. The final scale items were presented in Tables A1 and A2 (Appendix B).

Nomological Validity
To verify nomological validity, the actual level of consumer knowledge and purchase history were utilized. In the second survey, respondents were asked to name sustainable clothing brands that they are aware of and respond the proportion of sustainable clothing products in their closet. Based on the responses, the actual level of awareness and behavior of SCCP were self-reported. Then, the correlation with the developed scale factors was analyzed. Table 5 shows the result of the correlation analysis. The correlations were found as significantly positive with ten developed factors, except BL. This means the scale shows a good reflection of the actual awareness and behavior of consumers.

Discussion
This research conducted the theoretical consideration to develop the scale for the sustainable consumption of clothing products (SCCP), examined a basis to structure related concepts and emphasized the need of a new approach for measuring the SCCP. The finalized scale constructs achieved (1) dealing with the overall consumption stages of clothing including purchase, use and disposal stages, (2) containing impact-oriented behaviors such as buying less or replacing of a new clothing merchandise and (3) including previously neglected aspects, such as gender issues, animal rights and design ethics issues related to clothing products. It consists of the total 52 items including 22 awareness items and 30 behavior items. Items of the final scale are results of the scientific and statistical verification and guarantee the reliability and validity. In this process, both qualitative and quantitative methods such as statistical verification were used together through the complementary procedure. It has academic contribution in that it prepared a measuring tool for SCCP which can lead to immediate academic application and correct measurement.
The development of the scale of the SCCP has scholarly contributions as follows: First, it has significance in that it identified multi-dimensional constructs to suggest concepts of the SCCP in an integrated and comprehensive manner. At a time when the importance of the sustainable consumption increases and a new mode is imposed upon clothing production and consumption, SCCP has been partially dealt with in various studies along with different definitions. Before the main survey, this study examined and summarized a variety of precedent studies, identifying a theoretical background and implementing a systematic classification. Hence, it conceptually specified the SCCP under the consideration of both direct and indirect influences in the entire clothing consumption processes and included a lot of aspects related to the theme. It structured the SCCP through the examination of awareness composed of knowledge and belief and also impact-oriented and intent-oriented behaviors. As for the methodology, those which may be overlooked in literature research alone were complemented by qualitative research.
The second is to construct the scale of SCCP reflecting the uniqueness of clothing consumption and to expand a theme for discussion. With a focus on purchase, prior research limited a sustainable clothing consumption concept to behavioral perspective, especially purchase wise or it considered attitude or norm towards general environmentalism as antecedent variables of behavior. This research focused on reflection of the uniqueness of clothing consumption, considering its specificity. In particular, it constructed various behaviors as a measuring item, including impact-oriented behaviors and activism behav-iors. In fact, exploratory research on sustainable clothing consumption focused on various behavioral aspects like management of a wardrobe/life of a garment, styling and consumption reduction mainly by interviews [38,68]. By using the scale of this study, it is possible to quantify a level of consumer awareness and consumer behavior through measuring in many aspects and consumption stages of SCCP.
The followings are suggestions that clothing researchers have to consider for their research using this scale: In the developmental phase of the scale, measurement was conducted and verified based on seven-point Likert scale (one-seven points). In the research hereafter, it is possible to obtain the most desirable results when measuring based on seven points too. In addition, the scale examines the sustainable clothing consumption under the division of awareness and behavior and, the goodness of fit was verified for awareness and behavior separately. Therefore, they are able to use either awareness or behavior only, according to a research model. Besides, five factors were derived from awareness and six factors from behavior and the reliability of each factor was verified. Accordingly, it is possible to independently use measurement items corresponding to each factor according to a research topic. For instance, if a research topic is the consumption of eco-friendly clothing, only knowledge of environmental impacts by clothing products may be set as an independent variable and it can be examined as an antecedent variable of purchase intention for eco-friendly garments. However, the ultimate goal of the development of the scale was to help consumers with their comprehensive diagnosis and understanding of the sustainable clothing consumption, rather than focusing on repective awareness and behavior. Therefore, instead of using separate factors, comprehensive measurement is recommended. In order to evaluate the sustainable clothing consumption comprehensively with a focus on consumers, basic data about consumer awareness and behavior should be prepared through continual measurements and reports of every factor. Especially, rather than persisting with the linear order of knowledge-attitude-behavior, it is expected to give a suggestion for the complex and circular relationships including the effect of value, situation, institutional environment and personal conditions on awareness and behavior and the impact of behavior on awareness. Lastly, since the tested sample was limited to young Koreans in this study, it is recommended to conduct factor analysis first for item purification and validation before applying a new sample under a different cultural background.
The measurements from the scale of this research may produce basic data to give policy suggestions for accelerating SCCP in real consumer lives. It may be used as the theoretical resource for policy making by understanding the demographic and clothing consumption characteristics for a group lacking in information or knowledge. For example, since a group with a low level of awareness and behavior may be understood as those who have insufficient information about sustainable garments, strategies tailored to their needs can be established including the development of an educational program or distribution of a brochure. As another example, for a group with a low belief in SCCP, they can be given a discount on a sustainable garment on the market or education about positive effects by the SCCP, increasing their opportunities to experience such a product and improving their awareness and behavior. In a managerial perspective, a fashion enterprise, when positioning its brand as a sustainable clothing brand and searching for target consumers, can concentrate on sales promotion by targeting an adequate group. Furthermore, it can promote opportunities for attracting a lot of customers and changing culture gradually while planning a marketing campaign simultaneously to lead consumers of a high or low involvement group to those of an active involvement group.  Informed Consent Statement: Informed consent was obtained from all subjects involved in the study.

Data Availability Statement:
The data presented in this study are available on request from the corresponding author. The data are not publicly available due to the conditions of the consent statements signed by research subjects. I can contribute to make our society and the earth better by sustainable clothing consumption. BSC4

Appendix B
Sustainable clothing consumption helps me with getting aesthetic satisfaction. BSC5 I can be recognized as a socially good person through sustainable clothing consumption.

MCB1
I put emphasis on eco-friendly in clothing consumption. MCB2 I think it is important whether a garment was made in an eco-friendly manner. MCB3 I greatly consider on whether rights of a laborer were guaranteed in the production when buying a garment. MCB4 I put stress on whether a garment was produced by a moral company when buying. MCB5 I emphasize on whether production was involved in unnecessary animal killing when making purchase. MCB6 I try not to buy a garment violated the intellectual property right(check if it is an imitation).

MCB7
It is important for me to see whether a garment is helpful for establishing the just gender culture when buying.

SPB1
I prefer to purchase a garment with "Green" or "fair trade" mark.

SPB2
I usually purchase a garment after checking information related to eco-friendly including organic cotton, eco-friendly dyeing and upcycling.

SPB3
I purchase a garment after checking information about social issues including labor, animal and intellectual property rights.

SPB4
I give priority to a company making efforts for eco-friendly/pro-social production and distribution of garments when buying.

SUDB1
I keep a garment well according to instructions on a laundry label. SUDB2 I store and keep a garment considering its kind to prevent damage. SUDB3 I wear a garment a little ragged with or without repair. SUDB4 I try to wear clothes with a new combination. SUDB5 I often rearrange my closet to know what garments I have. SUDB6 I donate clothes or give them to an acquaintance who needs it when disposing of clothes. SUDB7 I separate items for recycling and disposal when disposing of clothes.

AB1
I get education or participate in a campaign for sustainable clothing consumption. AB2 I joined an online community or an offline group meeting for sustainable clothing consumption. AB3 I often get new information about sustainable clothing consumption through SNS or portal search. AB4 I actively encourage my family or acquaintances to practice the sustainable clothing consumption. AB5 I share my knowledge about sustainable clothing and brand with people around me.

BL1
I avoid impulse buying when purchasing a garment. BL2 I think that purchase of a new garment has to be done to a minimum. BL3 I purchase a garment after checking its durability to use for a long time. BL4 I do not purchase a garment which does not match the one I have.

SVR1
I consider a secondhand clothing firstly when buying a garment. SVR2 I often purchase an old or a vintage garment. SVR3 I often use clothing rental services.