Determinants of followers' purchase intentions toward brands endorsed by social media influencers: Findings from PLS and fsQCA

Given the rise of marketing through social media influencers (SMIs), this study aimed to investigate the influences of source credibility and content validity factors on followers' attitudes and intention to purchase brands endorsed by SMIs through brand engagement and brand expected value. The study assessed the moderating effect of product-influencer congruency. Data were collected from 429 individuals in Iran and were assessed using the "partial least squares" (PLS) and "fuzzy-set qualitative comparative analysis" (fsQCA) approaches. PLS results affirmed the significance of all direct relationships except the role of entertainment value on brand engagement and informativeness value on brand expected value. Product-influencer congruence positively moderated the effects of trustworthiness and expertise on brand expected value. fsQCA identified five solutions with various combinations of elements that lead to high purchase intention. The results of performing fsQCA revealed that three factors, namely attractiveness, entertainment value, and attitude, are necessary to achieve high purchase intention. fsQCA results challenged the PLS findings, indicating the importance of using an asymmetric approach in conjunction with PLS. Our study provides valuable insight for marketing influencers and practitioners on the importance of source credibility and content value factors in enhancing the effectiveness of SMI marketing activities and persuading customers to purchase endorsed brands.