Exploring the consistency of WOM senders on SNS: a combined approach of PLS-SEM and necessary condition analysis (NCA)

Purpose This study investigates how the valence of WOM (Word-of-Mouth) influences senders' brand attitudes and behavioral engagement. Grounded in theories of cognitive consistency and cognitive dissonance, status quo bias, and WOM, this study investigates the effects of positive and negative WOM on brand love, brand hate, and behavioral engagement. Furthermore, it examines the asymmetric mechanisms by which expressed sentiments lead to behavioral outcomes. Design/methodology/approach Survey data were collected from 433 patrons who had recently interacted with food service brands via SNS platforms. SmartPLS 4.1 was utilized to test the proposed structural model, and Necessary Condition Analysis (NCA) was employed to identify critical prerequisites for engagement. Findings The results reveal an asymmetric WOM sender effect: while positive WOM significantly enhances both brand love and behavioral engagement, negative WOM amplifies brand hate but does not significantly reduce behavioral engagement. These results suggest that customer inertia driven by status quo bias buffers the impact of negative affect on behavior. Mediation analysis further indicates that negative WOM indirectly harms engagement by eroding brand love, which NCA identifies as a critical necessary condition (threshold approx. 48%) for high behavioral engagement. Research limitations/implications This study redefines the WOM sender effect through an asymmetric lens. Theoretically, it integrates status quo bias to explain why negative sentiment does not precipitate disengagement. Managerially, firms should not overreact to negative WOM from “Grumbling Loyalists.” Instead, they should provide safe venting channels while monitoring brand love levels. Originality/value This study contributes to the literature by shifting the focus from the receiver to the sender and uncovering the unintended consequences of the sender effect. It challenges the traditional assumption of symmetric consistency by demonstrating that while positive expression actively fuels engagement, negative expression does not necessarily lead to disengagement due to the overriding force of habit. The study offers insight on managing grumbling loyalists.