The Effects of Social Proof and Influencer Authenticity on Purchase Decisions: The Moderating Role of Consumer Skepticism Among TikTok Shop Users in Medan

Source abstract

This study aims to examine the effects of social proof and influencer authenticity on purchase decisions, and to test the moderating role of consumer skepticism among TikTok Shop users in Medan. A quantitative associative research design was employed. Primary data were obtained through a structured questionnaire distributed to 100 respondents selected via non-probability accidental sampling, using a five-point Likert scale. Data collection was conducted between June and August 2026. Data were analyzed using Partial Least Squares Structural Equation Modeling (PLS-SEM) with SmartPLS 4.0, involving measurement model evaluation, structural model estimation, and bootstrapping for hypothesis testing. The results indicate that social proof (β = 0.199; p = 0.046) and influencer authenticity (β = 0.375; p < 0.001) exert positive and significant effects on purchase decisions. Consumer skepticism also has a positive and significant direct effect on purchase decisions (β = 0.408; p < 0.001). However, consumer skepticism does not significantly moderate the effects of social proof (β = 0.102; p = 0.243) or influencer authenticity (β = −0.123; p = 0.156) on purchase decisions. The full structural model explains 84.1% of the variance in purchase decisions (R² = 0.841; Adjusted R² = 0.832). These findings extend social proof theory and source authenticity literature in the social commerce context and provide managerial guidance for TikTok Shop sellers and marketers in designing credible, transparent promotional communications.