Research Proposal: Consumer Behavior in the Age of Influencer Marketing

The Impact of Influencer Marketing on Consumer Purchasing Decisions

Influencer Marketing becomes a $24 billion global industry in the year 2025 as a gauge of its continued utilization as a marketing approach (Migkos et al., 2025). Consumer behavior and the effectiveness of influencer marketing are the subjects of this research study. Research contribution is towards the potential understanding of psychological and behavioral mechanisms of consumer response towards influencer endorsements. With conventional promotion decreasing effectiveness through repeated exposure fatigue and mistrust, promotion through an influencer offers an apparently natural alternative. However, suspicion still reigns as much across a broad spectrum of consumer audiences as across product kinds. Understanding of such mechanisms informs marketers' deliberation of campaign best practice, and regulators are confronted with ethical issues such as undeclared sponsorships. Here, we suggest research as a contribution to the knowledge and practice of applied marketing.

Literature Review

Influencer marketing revolutionized contemporary advertising with social influencers' credibility and relatability used to influence consumer behavior (Migkos et al., 2025). Contemporary research has a number of key themes. Initially, the influencer's credibility of expertise, trustworthiness, and attractiveness has a primary impact upon the formation of consumer attitude and purchase intentions (Hossain et al., 2025). Research suggests that influencers are perceived as less professionally obvious and therefore more genuine, fostering emotional resonance with their audiences (Hossain et al., 2025). Credibility and relatability drive persuasion through less overtly commercial promotion, where influencers use personal product use as a reference. For example, Barari et al. (2025) demonstrated that micro-influencers with small but engaged audiences preferred their macro counterparts as drivers of increasing purchase intentions through relatability and specialism through their niche nature.

Consumer psychology also drives influencer marketing success. Social identity theory posits that consumers will buy from influencers with similar values, goals, or social identities and promote identification and affiliation (Pan et al., 2024). The Elaboration Likelihood Model (ELM) also helps explain consumers ' processing of influencer posts. Consumers with high involvement process central cues like high knowledge of a product, and low-involvement consumers process peripheral cues like an influencer's beauty or their number of followers (Hasan et al., 2024). The two-processing framework provides further insight into why influencer success or failure differs across contexts. For instance, Migkos et al. (2025) established that young consumers, especially Gen Z and Millennials, are more vulnerable to influencer endorsements because they are heavy social network participants and rely on peer-like figures.

Congruence of an influencer's specialty with the proposed product also takes precedence. Research suggests that the congruence of an influencer's area of interest (e.g., fitness, beauty) with a product category enhances credibility and purchasing intentions (Hossain et al., 2025). Over-commercialization also has a downside. Theodorakopoulos et al. (2025) said repeated use of paid posts leads to "influencer fatigue" and dilutes trust and interest. Ethical complications, such as undeclared sponsorships, further muddy the waters as research suggests openness attenuates suspicion (Waltenrath, 2024). Demographic effects also mediate success with females and younger demographics, who positively receive influencer promotions.

Despite these insights, research gaps persist. Most studies focus on single platforms like Instagram, limiting generalizability across emerging platforms like TikTok. Additionally, the interplay between influencer type (micro vs. macro) and product category (hedonic vs. utilitarian) remains underexplored, as does the role of cultural differences in shaping responses (Hossain et al., 2025). This study addresses these gaps by examining how influencer marketing influences purchasing decisions across diverse platforms, demographics, and product types, contributing to a more nuanced understanding of consumer behavior in the digital age.

Research Questions and Hypotheses

This study seeks to answer the following research questions:

1. How does influencer credibility (expertise, trustworthiness, attractiveness) influence consumer purchasing decisions across different product categories?
2. To what extent does the congruence between an influencer’s niche and the endorsed product affect consumer purchase intentions?
3. How do demographic factors (age, gender, income) moderate the effectiveness of influencer marketing campaigns?

Based on the literature, the following hypotheses are proposed:

• H1: Higher influencer credibility (expertise, trustworthiness, attractiveness) positively affects consumer purchase intentions.
• H2: Greater congruence between an influencer’s niche and the endorsed product increases consumer purchase intentions.
• H3: Younger consumers and females exhibit stronger purchase intentions in response to influencer marketing compared to older consumers and males.
• H4: The effect of influencer marketing on purchase intentions varies by product category, with stronger effects for hedonic products (e.g., fashion) than utilitarian products (e.g., household goods).

Methodology

Research Design

This study employs a mixed-methods approach to provide a comprehensive understanding of influencer marketing’s impact. A quantitative survey will assess consumer purchase intentions and attitudes, while qualitative focus groups will explore underlying motivations and perceptions. This design allows triangulation of data to enhance validity.

Sampling Method

The target population includes social media users aged 18–45, as this group is most active on platforms like Instagram, TikTok, and YouTube, where influencer marketing thrives. A stratified random sampling technique will be used to ensure representation across age groups (18–25, 26–35, 36–45), gender, and income levels. A sample of 500 participants will be recruited via an online panel provider (e.g., Qualtrics), ensuring diversity in geographic location and social media usage. For focus groups, 24 participants (three groups of eight) will be purposively selected from the survey sample to represent varied demographic profiles.

Data Collection Techniques

• Quantitative Survey: A structured online questionnaire will be developed, incorporating validated scales from prior studies. For example, influencer credibility will be measured using Ohanian’s (1990) 15-item scale, adapted for influencer contexts (Volkmer & Meißner, 2025). Purchase intention will be assessed using a 5-item scale. The survey will include scenarios featuring different influencer types (micro vs. macro) and product categories (hedonic vs. utilitarian) to test hypotheses. Responses will be collected on a 7-point Likert scale.
• Qualitative Focus Groups: Three 60-minute focus groups will be conducted virtually to explore consumer perceptions of influencer authenticity, trust, and purchase motivations. A semi-structured guide will include open-ended questions, such as “What makes you trust an influencer’s product recommendation?” Discussions will be recorded and transcribed for thematic analysis.

Data Analysis

Quantitative data will be analyzed using SPSS. Descriptive statistics will summarize sample characteristics, while multiple regression analysis will test hypotheses H1–H4, examining the relationships between influencer credibility, congruence, demographics, and purchase intentions. ANOVA will explore differences across product categories. Qualitative data will be analyzed using NVivo for thematic coding, identifying patterns in consumer perceptions. Triangulation will integrate findings to provide a holistic view.

Expected Outcomes

This study is expected to confirm that influencer credibility significantly drives purchase intentions, with trustworthiness being the most influential dimension. Congruence between an influencer’s niche and the endorsed product is likely to enhance persuasion, particularly for hedonic products like fashion or beauty, where emotional appeal is paramount. Younger consumers and females are expected to show stronger responsiveness, aligning with prior findings on demographic influences (Defta et al., 2025). However, the study may reveal weaker effects for utilitarian products, where functional attributes dominate decision-making.

These findings will have significant implications for marketing strategies. Brands can optimize influencer selection by prioritizing credibility and niche alignment, tailoring campaigns to specific demographics and product types (Hossain et al., 2025). The qualitative insights will shed light on consumer skepticism, such as concerns about over-commercialization, guiding ethical practices like transparent disclosures (Waltenrath, 2024). The results may also inform policymakers on regulating influencer marketing to protect consumers from deceptive practices.

Limitations

While this study aims to provide a comprehensive analysis of consumer trust in social media influencers, several inherent limitations must be acknowledged, as they delineate the boundaries of the research and offer directions for future inquiry. Mainly, the primary reliance on self-reported data collected via surveys presents a significant challenge (Shipman et al., 2023). This approach is subject to a number of response biases that could distort findings. Most commonly, social desirability bias has a high chance; participants will consciously or subconsciously report socially desirable or desired responses as opposed to what actually reflects their attitudes and behaviors. For research purposes, this could manifest as exaggerated confidence in influencers or underestimation of impulsive buying behaviors as motivated by influencer messages. Even as standardized scales will act as a gatekeeper of ascertaining the measure's reliability through an array of methods, a basic limitation of the self-reported method lies with the fact that the data reflects perceived trust and can differ from true consumer behavior in a marketplace.

Also at issue are the problems of generalizability or external validity. While the sampling approach aims to capture diversity in age and gender, the research scope may not reflect the expansive panorama of global consumer behavior. Social media practices, attitudes toward trust, and the nature of influencer promotion are ingrained into cultural settings (Defta et al., 2025). For example, consumer-influencer relations from Eastern markets could function in other paradigm settings than Western ones. As such, while the results can prove valuable for specific demographic groups or locales, it is not advisable to extrapolate them directly to the global population without subsequent cross-cultural verification.

Moreover, the platform-centric focus of the research introduces a potential blind spot. The study deliberately concentrates on three established platforms: Instagram, TikTok, and YouTube. While these represent dominant forces in the current landscape, the social media ecosystem is notoriously dynamic (Hossain et al., 2025). New platforms continuously emerge, and consumer attention can shift rapidly. By not including nascent or niche platforms that might gain prominence during or after the study period, the research risks overlooking innovative forms of influencer engagement and evolving trust-building mechanisms that occur outside the examined triumvirate.

Finally, the chosen mixed-methods approach, while a strength in its potential for triangulation, presents its own integrative challenges. The process of merging quantitative data (numerical scores on trust scales) with qualitative data (rich, textual insights from interviews) is complex (Waltenrath, 2024). There is a risk that the differing nature of these data types could lead to difficulties in achieving a fully cohesive interpretation, where one dataset might appear to contradict the other without a clear explanatory narrative.

To mitigate these limitations, several strategies will be implemented. For the survey data, previously validated scales will be used, and anonymity will be emphasized to reduce social desirability pressures. Thematic analysis for qualitative data will be conducted with rigor, using multiple coders to ensure reliability (Waltenrath, 2024). Most importantly, these limitations will not be dismissed but will be explicitly acknowledged and thoughtfully discussed in the interpretation of the results, framing them as valuable avenues for subsequent research.

Conclusion

This proposal outlines a comprehensive study to investigate the impact of influencer marketing on consumer purchasing behavior, which is a central theme of modern marketing. By integrating quantitative surveys and qualitative focus groups, the study will describe the role of influencer credibility, niche appropriateness, and demographic factors in shaping consumer behavior for various product categories. The findings expected will offer managerial implications for enhancing influencer marketing campaigns by marketers, with special attention to authenticity and personalized campaigns to maximize engagement. Furthermore, the study will contribute to the literature by addressing gaps in platform-specific and demographic-focused research, while informing ethical guidelines for open influencer marketing. Notwithstanding potential limitations such as self-report biases and platform focus, the mixed-methods approach offers promises of rigorous findings.