Amendment of VAT returns and its impact on sales: a tax control proposal

Abstract

This study addresses the issue of recurring changes in Value Added Tax (VAT) declarations made by small and medium-sized enterprises (SMEs) in Ecuador, analyzing their impact on declared sales and tax revenue. For this reason, the objective was to examine the relationship between these changes and declared sales, as well as to propose tax control measures aimed at reducing this practice and mitigating tax evasion. The research was developed under a non-experimental documentary design, with a qualitative-analytical approach, based on secondary sources published between 2020 and 2025. The information was systematized through a documentary analysis matrix, which allowed for the classification of causes, effects, and proposed measures in the literature. The results showed that 34% of SMEs filed at least one substitute declaration in the same fiscal period, generating average variations of 12% in the VAT taxable base. The main causes were errors in sales recording, poor management of electronic receipts, and the absence of preventive verification mechanisms. It is concluded that there is a direct relationship between the frequency of modifications and the instability of declared sales, which affects tax reliability and national revenue. From this diagnosis, concrete measures are proposed: preventive coherence control, segmentation of taxpayers by risk level, training programs, and intensive use of electronic invoicing, actions that, if implemented gradually, could reduce tax evasion and strengthen tax compliance in the sector.