Sponsored advertising on social media and purchase intention: an attitude-mediated TPB–ELM model among Saudi consumers

Sponsored advertising on social media has become the dominant channel through which brands reach consumers in digitally advanced markets, yet the psychological mechanisms linking such advertising to purchase intention remain incompletely understood—particularly in culturally distinctive markets such as Saudi Arabia. Drawing on the Theory of Planned Behavior and the Elaboration Likelihood Model, this study tests a partial TPB–ELM integration in which advertising-related predictors shape purchase intention both directly and indirectly through attitude, and in which ELM persuasion routes determine whether the resulting attitude change is deep and durable or heuristic and transient. A quantitative cross-sectional survey was administered to active Saudi social media users recruited through platform-stratified quota sampling across Instagram, Snapchat, and X. Multiple linear regression, independent-samples t-tests, oneway ANOVA with Tukey HSD post-hoc testing, and Partial Least Squares Structural Equation Modeling (PLS-SEM via SmartPLS 4) were employed. The instrument demonstrated strong reliability and validity, and common method bias diagnostics confirmed no serious threat to the findings. Multiple regression showed that ad content quality was the strongest predictor of purchase intention, followed by influencer credibility/trust, consumer engagement, and ad exposure, with the full set of predictors jointly explaining a substantial share of variance. PLS-SEM confirmed all structural paths as significant, and a bootstrapped mediation analysis confirmed that attitude (TPB) partially mediates the ad exposure-purchase intention relationship—extending prior Saudi and regional evidence on TPB attitude mediation by testing this pathway within an integrated TPB–ELM structural model for sponsored advertising. Purchase intention varied significantly by age, with the 25–34 cohort showing the highest scores; gender differences were treated as exploratory given residual sample imbalance.