Green Authenticity Paradox: When Sustainability Claims Strengthen or Weaken Brand Credibility in Digital Marketing

3. METHODOLOGY

3.1. Research Design

Following Research Onion for methodology and design, the current study is based on pragmatism philosophy, abductive approach, which is used to test the hypothesised relationships. Experiments (mono-quantitative) was used mainly, with a qualitative phase to gain deeper understandings. The method used was mixed methods. Time horizon was cross sectional. Controlled experiments, focus group methods were the techniques employed for data collection and purposive sampling was used. MANCOVA, ANOVA and t-tests were used for qualitative data analysis, as well as thematic analysis.

3.2. Quantitative Phase

The quantitative portion of this research adopted the experimental research design to test how the different kinds of sustainability claims (no claim, vague claim and verified claim) and platform (social media and brand-owned websites), Perceived Green Authenticity and Consumer Scepticism affect the perceived brand credibility and purchase intention. For the vague claim, participants were exposed to advertisements with statements such as ‘We are committed to sustainability’ or ‘Our products are environmentally friendly’. Such statements were broad and did not have any backing evidence or qualifications that could be interpreted in any way and thus could lead to scepticism. The attested assertions had quantifiable and clear certifications of sustainability, such as ‘Certified by [XYZ Eco-Label]’ or ‘100% recyclable materials, verified by [Third-Party Certification]’. These allegations were concrete evidences and meant to appeal to a greater degree of credibility and trust. In order to give a context, the participants were provided with a screenshot of the advertisement or a script of the message appearing on the platform. As a case in point, in the verified claim condition, the ad would incorporate a logo such as [XYZ Eco-Label] and a statement: ‘Our products meet the [XYZ] sustainability standard, verified by [Third-Party Certification]’. In the vague claim condition, the ad stated, ‘We care about the environment and are committed to sustainability. ’ The advertisements were shown in two channels, which included social and brand-owned sites. On each type of claim (no claim, vague claim and verified claim), the participants were shown the corresponding ad on one of these platforms to investigate the effect that the type of platform had on the perceived credibility and purchase intention. The experiment was aimed at establishing a realistic marketing situation so as to establish the effects of discrepancies in claim authenticity and platform type on consumer purchase intention and perceived brand credibility.

Claim type and platform type were operationalised as categorical independent variables following a controlled experimental design. Specifically, claim type was a between-subjects factor with three levels: (1) no claim, (2) vague claim and (3) verified claim. Platform type was operationalised using a between subjects 2-level experimental design with social media platform and brand-owned website being the two levels. The design was a fully between subject’s design with participants randomly allocated to one of the three claim conditions and then evenly distributed among the two platform conditions in each claim condition. This led to an even distribution of exposure into all experimental cells so that cells with a total of n = 50 were provided (six cells total). Random allocation helped to reduce selection bias and facilitate the inference of cause and effect of sustainability claim authenticity and communication platform on consumer responses. This factorial design allowed for systematic examination of the main effects and interaction effects in regard to perceived green authenticity, consumer skepticism, brand credibility and purchase intent.

In the current research, Perceived Green Authenticity (PGA) is considered as an exogenous evaluative orientation and Consumer Scepticism (CS) as an exogenous moderating variable, both of which have their origin in consumer cognition. In the UK manufacturing setting, sustainability communication is equated with existing perceptions of authenticity and scepticism in isolation which affect credibility notions and purchase intentions. Attribution Theory provides a justification for this view by arguing that consumers assign motives, sincerity and ethics to sustainability claims based on their pre-conceived assessment of them. (Shin & Ki, 2021). Furthermore, the design of the study revealed that they listened to different claims prior to making their authentic perception and sceptical responses as direct reaction to the claims. To this end, PGA and CS are not regarded as intermediate or moderating variables in the communication of sustainability, but as explanatory variables that can explain the outcomes of the consumption process.

A total of 600 people were contacted through LinkedIn and the official social media pages of the UK manufacturing firms. Among them, 320 responses were obtained, yielding a response rate of 53.33%. After filtering out invalid and missing data, 300 valid responses were used for the analysis. The purposive sampling method was used, as suggested by (Makwana et al., 2023), which allows for the inclusion of participants who are familiar with the concept of sustainability communication and digital marketing practices, which is aligned with the core aim of the study. The unit of analysis was individual consumers exposed to sustainability advertisements of manufacturing-sector brands. The target population comprised UK consumers familiar with sustainability communication and digital marketing platforms.

The sample size was calculated using the GPower software for an F-test, MANOVA: fixed effects, special, main effects and interactions, with medium effect size (f² = 0.15), α = 0.05, and statistical power (1−β) = 0.80, suggesting that the minimum sample size for this analysis is about 300, which was considered for the current investigation. It validates the adequacy for analysis, as argued by (Jhantasana, 2023), and also indicates that it is suitable for analysing causality using the said method. Non-response bias was assessed by analysing the significance of the difference between early (n1 = 30) and late (n2 = 30) respondents using independent-samples t-tests; no significant difference was found, indicating no selection bias. Further, the selection bias was reduced by selecting the participants who represented a variety of manufacturing sub-sectors and job positions.

In addition, the participants were randomly divided into three experimental groups (100 per group), which would reflect the conditions of claim types, that is, (1) no claim, (2) vague claim, and (3) verified claim. The subjects were presented with an advertisement stimulus tailored to the type of their assigned claim, which was alternately shown on a social media interface and brand-owned websites to simulate real-life exposure. After exposure to the advertisement, the study subjects completed a quantitative questionnaire that gauged consumer scepticism, perceived green authenticity, perceived brand credibility, and purchase intention using a 5-point Likert scale, as depicted in Appendix A.

Following this, a few study subjects participated in a focus group session, during which 6 participants were interviewed using semi-structured questions based on open-ended questions related to the study’s objectives. The session lasted approximately, during which participants were asked about the advertisement shown and their perceptions regarding the claim types, platform types, consumer scepticism, perceived green authenticity, and how these factors affect their purchase intention and perceived brand credibility. Moreover, a quantitative questionnaire that gauged consumer scepticism, perceived green authenticity, perceived brand credibility, and purchase intention. Data were filtered for completeness, outliers, and valid responses; 300 responses were obtained, with a response rate of about 60%.

To analyse the data, the study used MANCOVA, One-way ANOVA, and independent-samples t-tests to examine causal relationships between independent and dependent variables and to compare means across the three groups of claim types, as suggested by (Alassaf & Qamar, 2022) as well. This design allowed testing hypothesised effects under controlled conditions, providing strong empirical evidence on the effects of sustainability claim authenticity and communication platform on consumer perceptions and behavioural intentions.

3.3. Qualitative Phase

The qualitative stage used semi-structured questions to understand in detail how consumers understand sustainability claims and interpret authenticity in digital brand communication. The consumers, who are actively involved with sustainability-oriented and eco-brands in the UK manufacturing sector, participated in 6 participants. To ensure participants are relevant and have a clear understanding, professional sustainability forums, LinkedIn, and verified brand communities were used to reach them. A focus-group questionnaire comprising six semi-structured, open-ended questions was used to collect responses from 6 participants.

To reduce selection bias, participants were selected to represent diverse demographics by gender, age, and occupation, thereby reflecting different consumer groups in the UK. The focus group session was conducted online via Zoom, which is highly practical in terms of accessibility and the flexibility it offers participants across the UK. The focus group session lasted about 120 minutes, allowing us to collect detailed viewpoints from the participants regarding the research problem. Thematic analysis was applied using the (Braun & Clarke, 2021) framework, which comprised recording, transcribing, and analysing data to identify recurrent themes related to trust, authenticity, and credibility in sustainability communication.

4. RESULTS

4.1. Quantitative Findings

4.1.1. Demographic Profile Analysis

The statistical results in Table 1 depict the demographic profile of the research participants. It can be observed that among the total (n = 300) participants, 58.53% were male and 41.67% were female. On the other hand, in terms of age groups, 41.67% of the participants fall within the age category of 25-34 years, 33.33% within age category of 35-44 years and 25 % within age category of 45-54 years. Moreover, in terms of occupation, 25% of the study participants were students, 45% were employed, and 30% were self-employed. Lastly, with regards to the consumption pattern of the sustainable products by the participants, 25% consume it once a week, 33.3% once a month, and 41.7% yearly.

Table 1. Demographic profile.

4.1.2. MANCOVA Analysis-Platform Type

The MANCOVA results depicted in Table 2 shows substantial multivariate relationship of Consumer Scepticism (Wilks’ λ = 0.965, p = 0.006) and Perceived Green Authenticity (Wilks’ λ = 0.881, p < 0.001) with the dependent variables, Perceived Brand Credibility and Purchase Intention. In addition, interactions amongst Platform Type were insignificant within both Consumer Scepticism (p = 0.895) as well as Perceived Green Authenticity (p = 0.673). Consumer Scepticism (CS) shows a statistically significant multivariate relationship (Wilk’s λ = 0.965, p = 0.006) as a result of which sceptical consumers have a systematic difference in their attitudes to assessing brand credibility and purchase intentions.

Table 2. MANCOVA results with platform types and covariates.

The multivariate effect of Perceived Green Authenticity (PGA) is also highly significant (Wilk’s λ = 0.881, p = 0.001), indicating a substantial contribution to improvements in brand credibility perceptions and consumer purchase intentions. Platform Type interactions Platform Type x CS (Wilk’s λ = 0.999, p = 0.895) and Platform Type x PGA (Wilk’s λ = 0.997, p = 0.673), on the other hand, are not statistically significant which means that the presence of a sustainability message on social media or a brand-owned site does not change the relationship of consumer scepticism and perceived brand authenticity with brand credibility and purchase intention.

4.1.3. MANCOVA Analysis-Claim Type

The multivariate results, integrating claim type (Table 3), further strengthen the importance of message content in shaping consumer responses. Perceived Green Authenticity (Wilk’s λ = 0.890, p = 0.000) has a great multivariate impact that highlights the key role it plays in establishing a positive brand credibility and intentions to purchase. Similarly, Consumer Scepticism (CS) is also important (Wilk’s λ = 0.969, p = 0.010), indicating that sceptical attitudes strongly influence interpretations and actions regarding sustainability claims.

Table 3. MANCOVA results with claim types and covariates.

Importantly, both the effects of interaction- Claim Type x CS (Wilk’s λ = 0.881, p = 0.000) and Claim Type x PGA (Wilk’s λ = 0.889, p = 0.000) have significant values. This means that consumer scepticism and brand perceived authenticity vary greatly depending on the outcome of the types of claims, which are, verified, no, and vague. These results substantiate the fact that the nature and quality of sustainability communication as well as the consumer predispositions are related with the trust and behavioural intention in the UK manufacturing environment.

In the next step, to further analyse and elaborate on differences, one-way ANOVA and Independent Samples T-test are applied.

4.1.4. One-way ANOVA

The effect of claim type on the purchase intention and perceived brand credibility is analysed using One-way ANOVA. (Lionello et al., 2021) indicated the use of one-way ANOVA when difference is needed to be evaluated amongst three or more groups.

As per the results depicted in Table 4, purchase intentions of consumers in the UK manufacturing sector significantly differ between the three claim groups (P = 0.00 < 0.05). The findings show that consumers exposed to different claim types exhibit varying levels of purchase intention, with verified claims significantly enhancing purchase intention compared to no claim and vague claims (multiple comparisons). This confirms that verified sustainability claims are more effective in driving consumer behaviour and willingness to purchase.

Table 4. One-way ANOVA.

Note: *** p < 0.01 (significant at the 1% level)

However, the results indicate that claim type have a significant effect on Perceived Brand Credibility (PBC) (P = 0.023 < 0.05). It means that, the nature of the claim would have an impact on the purchase intentions, as well as credibility of the brand. However, the effect size was weaker than for purchase intention.

4.1.5. Independent Sample T-test

An independent-samples T-test is applied to examine whether there is a statistically significant difference between the means of two groups, as suggested by (Makwana et al., 2023) as well. It has been assessed if purchase intention and perceived brand credibility vary based on the platform type, such as social media or brand-owned website (Table 5).

Table 5. Independent sample T-test.

An independent-samples t-test is used to compare the responses of participants who were exposed to two types of platforms, such as social media and brand-owned sites. The findings indicate that there is no significant difference in purchase intention (PI) by platform (p = 0.879). Thus, consumers’ purchase intentions are the same whether the sustainability claim is posted on a social media feed or on the company’s official website. It means that the platform itself does not provide high purchase motivation.

However, there is a significant difference in Perceived Brand Credibility (PBC) across platforms (p = 0.019). The large-mean difference shows that the PBC on the social media was lesser than on the same claims on the brand-owned websites. It is a symptom of the growing trust of the consumers in the corporate-controlled communicative context, in which assertions are less careless than in the less controlled social media realm.

4.2. Focus Group Analysis

4.2.1. Demographic Analysis

The demographics of the entire focus group (n = 6) participants in the discussions were depicted in Table 6. The proportion of male to female among those respondents was 66.7:33.3. Conversely, 16.67% were in the 30-39 years age group, 50% in the 40-49 years age group and 33.33% in the 50 years and above age group. Although occupationally speaking, the participants were equal in number that is, 33.33% each student, corporate employee, and self-employed population.

Table 6. Demographic analysis.

4.3. Thematic Analysis

Theme 1: Authenticity as the Core of Sustainable Brand Credibility

This theme was also generated based on the consideration of the participants on what makes a brand seem truly sustainable (Table 7). It enabled the capturing of the connection under transparency, authenticity, and trust, which are main components of brand credibility.

Table 7. Themes table.

In response to this question, R1 stated, “I believe a brand is truly sustainable when it provides clear evidence of what it’s doing — not just buzzwords like ‘eco-friendly’ or ‘green.’”

This proves that consumers require factful evidence, not rhetoric and this argument is enough to prove that authenticity is a product of verifiable commitment, not symbolic marketing as it has been emphasised by (Kim et al., 2021) as well. This uncertainties in the message spoils credibility that is consistent with (Sander et al., 2021), who established that environmental specificity results in better perceived honesty.

Similarly, R4 remarked, “If a company shows real actions, like certifications or transparent reports, I’m more inclined to trust its green claims.

This brings out the authenticity of authentic assertions. (Suhud et al., 2022) suggest that authenticity intervenes in the connection between sustainability claims and positive attitudes and purchase intentions. Hence, transparency is a source of credibility and buying intention due to provable sustainability statements.

Theme 2: The Impact of Claim Type on Consumer Trust and Scepticism

This was a theme that was created due to the debates on the place of claim types, no claim, vague claim, or verified claim, in respect of trust and scepticism.

In response, R2 stated, “When a brand makes vague claims like ‘we care for the planet’ without showing how, it feels manipulative like greenwashing.”

This highlights the negative reaction to ambiguity, which are also noted by (Carranza et al., 2023), who concluded that ambiguous claims reduce trust and purchase intention.

Meanwhile, R5 shared, “I trust brands that back their sustainability messages with facts, data, or certifications; anything less feels like marketing fluff.”

Authenticated claims minimise scepticism, and this does not contradict (Bladt et al., 2024) who claim that evidence-based communication is more effective in enhancing green value. Alternatively, brands with no or vague promises fail to deliver expectations of transparency. Validated messages, thus, build confidence and credibility, and the uncertain messages build doubt and lack credibility over the internet.

Theme 3: Platform Context and Its Influence on Perceived Credibility

The significance of this theme emerged because of the fact that the effects that the nature of platform i.e. social media and brand owned websites can have on the perceptions of credibility were taken into consideration.

R3 noted, “When I see a sustainability claim on social media, I take it lightly. But if it’s on the brand’s official website, I feel it’s more reliable.”

This proves that platform credibility is an intermediate of interpretation. (Mabkhot et al., 2022) have also discovered that credibility and participation are determined by the source of messages and usefulness of the information. The perception of social media as more prone to exaggeration than websites, which possess the infusion and permanence, is based on the interactivity.

Adding to this, R6 mentioned, “Social media ads feel like hype — they focus on visuals over facts. The website feels official and evidence-based.”

This disparity reveals that credibility of the platform is what defines authenticity ratings. There is also a similarity to (Kim et al., 2021), who state that the persuasive ability of social media is determined by the reliability of information. As such, platform type is the moderating factor on the translation of authenticity cues into credibility that prompts firms to contextualise sustainability.

Theme 4: Verified Claims as a Driver of Purchase Intention through Perceived Authenticity

This theme was the result of the argument produced by the respondents on the impact of verified sustainability claims on purchasing intentions, according to which the nature of the claim and its verifiability is combined with behaviour.

R2 expressed, “When I see a verified logo or certification, it gives me confidence that the brand isn’t just talking — it’s actually doing something.”

These examples of R2 that confirm claims are a type of a trust signal, and they enhance purchase intentions by reducing the uncertainty. (Mabkhot et al., 2022) claim that this relationship is mediated by authenticity, which transforms credibility of claims into behavioural intention.

Likewise, R5 stated, “If the claim is backed by a reliable certification body, I feel my purchase contributes to something meaningful.”

These arguments point to the matching of values and support the arguments regarding consumer motivation and are compatible with (Kothari et al., 2025) who discovered that the development of online trust through authenticity, sustainability, and credibility is mutually formed. R1, however, indicated that where evidence lacks, it is nothing but green marketing spin. Authenticated claims are, as such, mental shortcuts to authenticity, and unspecified claims are suspicions.

Theme 5: Overcoming Consumer Scepticism through Transparent Digital Communication

This theme can be explained based on the contemplations about how a brand can be viewed as less sceptical and more authentic on platforms.

R6 stated, “Most brands exaggerate their green claims. I only start believing when they show consistent updates about progress — not just achievements.”

This reaction of R6 highlights that this is a long-term openness, and not a single campaign. It is also mentioned that long-term communication and value compatibility reduce scepticism and promote mindful consumption (Suhud et al., 2022).

R4 added, “I don’t mind ads, but I need to see proof — like videos from the factory or real impact stories — to feel the brand is credible.”

This is pointing to the increasing demand of authenticity. R3 also observed that the central aspect of sharing the message, in particular, social media, is transparency, because consumers can sense that something may be too good to be true, as (Bladt et al., 2024) pointed out. Such observations mean that, when it comes to conquering scepticism, there is a necessity to open, be consistent and to make the stories checked. Bidirectional clear-cut digital communication may transform the sceptical target customers to be loyal customers.

5. DISCUSSION

H1: There is a statistically significant effect of claim types on perceived brand credibility in the UK manufacturing sector.

The findings support H1 in the MANCOVA analysis; however, the one-way ANOVA not supported it. It showed a direct significant effect of claim type on perceived brand credibility (PBC) and purchase intention (PI). Participants in the qualitative phase emphasised the importance of evidence-based claims for building trust in sustainability efforts. Ambiguous claims were seen as manipulative, which aligns with (Ngo et al., 2024), who found that ambiguous claims generate suspicion rather than credibility. These findings confirm those of (Koh et al., 2022), who also emphasised the role of evidence-based communication to improve brand credibility. This difference with (Kim et al., 2021), who proposed that credibility can be created solely through the message, can be explained by the UK manufacturing industry’s already high awareness of greenwashing, reinforced by the Green Claims Code (Javed et al., 2024a). This opinion is supported by Attribution Theory, which shows that verifiable claims are regarded as real behaviours and, as such, the brand’s credibility improves.

H2: There is a statistically significant effect of claim types on consumer purchase intention in the context of the UK manufacturing sector.

The findings are highly in favour of H2, because the type of claim played an important role in consumer purchase intention. Participants’ intention to purchase was higher among those exposed to verified claims than among those exposed to vague or no claims. This observation aligns with the qualitative data, as claims of sustainability were, in most cases, correlated with higher levels of trust, which, in turn, affected purchase intention. These findings are consistent with those of Hosain & Mamun, 2023), who found that consumers respond better to brands that offer realistic, sustainable value rather than empty rhetoric. This disparity in consumer behaviour is attributable to the fact that consumer regulation in the UK manufacturing industry is emerging as a key driver of green performance reporting (Edie, 2025; Hu & Zhu, 2022). According to the Attribution Theory, once claims are verified, consumers will attribute them to the brand’s actual sustainability actions, thereby enhancing their intention to purchase the brand.

H3: There is a statistically significant difference between the perceived brand credibility impacted by platform types in the UK manufacturing sector context.

The results partly support H3, as the independent-samples t-test indicates that platform type significantly affects perceived brand credibility (PBC) and nor purchase intention. In contrast, the MANCOVA indicates that platform type significantly affects PBC and PIVA. Although participants favoured brand-owned websites for sustainability messaging, the credibility gap was not as significant as expected. The qualitative findings indicated that participants were highly critical of sustainability claims across platforms, suggesting that platform type have an uncertain impact on trust. This aligns with (Gani et al., 2023), who found that platform type may affect trust formation, though the veracity of this assertion is more important. Attribution Theory proposes that the credibility of the statement, rather than the platform, is the predominant determinant of consumer trust, and this aligns with the finding that platform type is not an important credibility factor.

H4: There is a statistically significant difference between the consumer purchase intentions impacted by platform types in the UK manufacturing sector context.

The results do not confirm H4 because platform type is not significantly associated with consumer purchases. Despite a slight inclination among participants towards brand-owned websites when sending sustainability messages, this inclination did not lead to a significant difference in purchase intentions. It is the opposite of the conclusions of (Dinana et al., 2025), who maintained that platform type influences consumer trust and decision-making. The difference might be explained by the fact that the UK manufacturing industry is highly oriented towards consumers who attach greater importance to verified claims and third-party guarantees, rather than the platform where the sustainability claim is made. Attribution Theory holds that the credibility of the message will prevail over the medium through which it is conveyed, and hence consumers will tend to make their purchasing decisions based on the credibility of sustainability claims rather than the platform used.

H5: The impact of Perceived Green Authenticity (PGA) on purchase intention is statistically significant.

The results confirm H5 and prove that the perceived green authenticity (PGA) has a significant effect on consumer purchase intention. The value of authenticity was maintained throughout the respondents, who always linked credible claims of sustainability to a higher degree of trust and a higher tendency to purchase. It coincides with the results of the (Bladt et al., 2024) study where they emphasised that authenticity plays a major role in the process of formation of brand credibility and purchase intention. (Isac et al., 2024) also assume that the consumer literacy levels on the topic of sustainability in the UK manufacturing sector have increased, and consumers have become more demanding of authentic and transparent claims. The Attribution Theory indicates that the perceived green authenticity allows the consumer to internalise sustainability as a brand identity element which, on the other hand, increases credibility and purchase intention.

H6: The impact of Perceived Green Authenticity (PGA) on Perceived Brand Credibility is statistically significant.

The results confirm the hypothesis (H6), because the perceived green authenticity (PGA) was significantly affecting the perceived brand credibility (PBC). The more brands credibly and verifiably promoted their sustainability, the more credible they became to the participants. This is in line with (Pittman et al., 2022) who discovered that authenticity is one of the main drivers of brand credibility. Transparency and substantiated claims are necessary in generating trust as indicated in the results, which reveal that substantiated sustainability claims increased both PBC and purchase intention. The Attribution Theory says that when a consumer perceives the green authenticity, there are higher chances that they will consider the brand as being truly devoted to sustainability, which has a positive impact on both PBC and purchase intention.

H7: The impact of consumer scepticism on purchase intention is statistically significant.

These findings are in favour of H7, since consumer scepticism has a considerable influence on purchase intention. The sceptical consumers had a lower purchase intention that was positive particularly in the presence of sustainability claims that were seen as unverified or unclear. This result is consistent with the qualitative outcomes, which revealed that the respondents were concerned about the issue of greenwashing and insincerity in certain sustainability practices. Such findings are in line with (Chuah et al., 2022), who established that consumer scepticism undermines the sustainability message efficacy. This research clearly has a contribution to the UK manufacturing industry, where mistrust based on the historical corporate malpractice is still high. According to the Attribution Theory, sceptical customers project sustainability statements on to a marketing strategy of manipulation, and not a strategy of actual action, diminishing the credibility of the brand and the desire to buy it.

H8: The impact of consumer scepticism on perceived brand credibility is statistically significant.

The results prove H8, which ascertained that consumer scepticism has a significant impact on perceived brand credibility. The sustainability claims had more chances of being distrusted by sceptical consumers, and this would harm the brand. This can be linked to (Carranza et al., 2023), who claim that consumer scepticism is a type of filter that will allow the consumer to reject sustainability claims as true. Attribution Theory goes on to imply that under high scepticism, consumers put sustainability claims under the influence of persuasive marketing instead of actual corporate practices, and therefore, reduces the credibility of the brand.