Do Influencers Influence? A Meta-Analytic Comparison of Celebrities and Social Media Influencers Effects

The emergent body of scholarship on social media influencers (SMIs) highlights their potential to yield positive brand advertising outcomes. However, the literature is undermined by the lack of clarity regarding how SMIs conceptually compare to celebrity endorsers and their impact on advertising outcomes. The study aims to clarify these differences via a meta-analysis of 39 experimental studies (total sample size = 13,766) of SMI effects from 2010 through March 2024. Findings reveal that SMIs are more effective than brand-only advertising and that there is no significant difference between SMIs and celebrity endorsers. Taking these factors into consideration, the effects are moderated by perceived credibility and influencer types, indicating that mega-influencers are relatively more persuasive, while nano-influencers are less persuasive compared to celebrities, respectively. Findings imply that there is a "sweet spot" wherein SMIs are most effective and distinct from celebrity endorsers, providing support for more nuanced conceptualizations of SMIs and calling for future research to explore additional enhancing and attenuating factors.