The second of the indicators provided for in the Strategic Plan to measure and evaluate the medium-term evolution of voluntary compliance with tax obligations is the measurement of the induced effects.

In order to improve voluntary compliance, the Tax Agency develops two main lines of action: on the one hand, assistance and prevention; and, on the other hand, the detection, regularization and, where appropriate, sanction of tax non-compliance through control actions.

Both lines of action are still two sides of the same coin: promoting voluntary compliance. In the first case, assistance and prevention, its purpose is clear; Regarding control actions, they not only pursue the regularization and payment of the defrauded contributions, but also the obtaining of optimal levels of tax compliance. In short, the aim is to redirect non-compliant taxpayers without it being necessary to carry out periodic control actions . By measuring the effects induced by these control actions, the aim is to measure both the impact of the complementary self-assessments that have been directly or indirectly induced as a consequence of the control activity, as well as the subsequent behavior of the taxpayer (or his or her environment). ) after control actions. These induced effects can occur in the year of verification (immediate) or in subsequent years (sustained).

Transparency initiatives and making tax data available to taxpayers also cause changes in their tax behavior, effects induced by verification actions, which can be quantified more easily.

Thus, for example, the information received through automatic exchange with countries of the European Union on income from work, directors, pensions and real estate income has been used to reinforce extensive control in the Personal Income Tax , both on non-filers and on filers who had hidden certain income obtained in other countries, of which there is now systematic knowledge. In 2021, and beyond the usual intensive control actions, these extensive control actions have generated settlements by the Tax Agency and untimely declarations by taxpayers for a combined amount of more than 51 million euros .

For years, the Tax Agency has established systems aimed at measuring the effect induced by inspection actions . The following table reflects the previous and subsequent behavior of the taxpayers verified by the Inspection area in the years 2014 to 2018 in comparison with the behavior of the total number of filers. Specifically, the evolution of the amounts of the self-assessments presented in the three years following the inspection verification is compared in relation to the three previous years .

As can be seen in the table, in general the inspected taxpayers increase their tax income to a greater extent than the group of taxpayers in the same time period which can undoubtedly be considered as a induced effect of control actions on taxpayers and shows how through control there is also an improvement in voluntary compliance.