Abstract

This study examines the effects of key determinants on consumers’ online shopping decisions in Vietnam, with a particular emphasis on Ho Chi Minh City. Drawing on consumer behavior theories and purchase decision-making theory, the research proposes a model in which perceived usefulness functions as a mediator, explaining how factors related to the online transaction experience are translated into purchase decisions. Based on a literature review and qualitative exploration to refine measurement scales and contextualize the research variables, the study identifies convenience perception, perceived health risk, and transaction speed as the main antecedents, while considering perceived value as a moderating variable to clarify the conditions under which the model's relationships strengthen. The study employs a mixed-methods approach, integrating qualitative and quantitative methods and using partial least squares structural equation modeling (PLS-SEM) to simultaneously assess the measurement and structural models, ensuring scale reliability, convergent validity, and discriminant validity prior to hypothesis testing. The results indicate that convenience perception, perceived health risk, and transaction speed all have significant effects on perceived usefulness; subsequently, perceived usefulness positively influences online shopping decisions, confirming its mediating role as a critical transmission mechanism. In addition, perceived value plays an important moderating role by strengthening the effect of perceived usefulness on purchase decisions. This finding implies that when consumers perceive higher “value for money” (i.e., greater benefits relative to costs), they are more likely to translate perceived usefulness into stronger purchasing behavior. Accordingly, the study suggests that e-commerce platforms should prioritize enhancing convenience, shortening transaction processing time, managing health-risk-related information appropriately, and strengthening value propositions to encourage consumers’ online purchase decisions.