The Mediating Role of Economic Pressure in the Relationship between Professional Ethics and Audit Quality: Empirical Evidence from Small and Medium-Sized Audit Firms in Hanoi

This study examines the impact of compliance with professional ethics on audit quality (AQUAL) in small and medium-sized audit firms (SMAFs) in Hanoi, considering the mediating role of economic pressure. Grounded in DeAngelo’s theory and the ethical standards framework of the International Federation of Accountants, an integrated model incorporating four ethical components: integrity, objectivity, professional competence, and professional behavior. The model was empirically examined using partial least squares structural equation modeling (PLS-SEM) methodology based on data collected from 176 validated survey re-sponses. The results confirm the positive direct impact of ethical factors on AQUAL (β = 0.228–0.320, p < 0.001) and the negative direct impact of econom-ic pressure (β = −0.319, p < 0.001). More importantly, economic pressure was found to play a significant partial mediating role, with meaningful indirect effects (β = 0.100–0.129, p < 0.001), accounting for 26.6% to 31.7% of the total effect. This demonstrates that professional ethics functions as a soft mechanism mitigat-ing the negative impact of economic pressure on AQUAL. These findings extend the “Cost-quality conflict” theory in an emerging market context and propose governance implications for ethics-infused training, minimum fee policies, and awareness of the value of quality audits.