Tax evasion is a complex social phenomenon found in most countries. This fraudulent behaviour has significant negative consequences to economic development (e.g., decreased public budget, increased administrative costs with audits) and social justice (e.g., tax evasion behaviours do not interfere with the use of public goods as health or education) and the fight against its harmful effects has been advocated by the main international organizations. Nevertheless, and in opposition to the majority of European Countries and the USA, integrative research on the factors that influence tax evasion in Portugal is inexistent. The existing surveys (e.g. INE, Eurobarometer, European Social Surveys, Ministry of Finance) do not take an articulated approach to the subject of psychosocial variables in tax evasion and the dominant approach mainly explores the juridical and rational agent economic perspectives of the individuals' relationship with the fiscal system (e.g., studies focus on the impact of audit probability or severity of penalty). Furthermore, the studies performed on this subject that include social or psychological variables are restricted to the single analysis of each category of variables, neglecting a combined examination of factors and their possible interactions.

The current project has the purpose to explain, predict and prevent tax evasion in Portugal, identifying the impact of individual (e.g., values, beliefs, risk perceptions), economic (e.g., tax rate, audit probability) and social (e.g., trust in Government, religion) factors that influence fraud behaviour. This research was structured in a sequential way to embrace both qualitative (focus groups) and quantitative (survey and experimental studies) data, crucial to understand and intervene in tax evasion behaviour. The project was developed by a multidisciplinary team, directed by sociologists and including economists and psychologists, in a combined effort to integrate scientific approaches with the double purpose of (a) replicate, improving previous research performed in other countries that provide an essential contribution to elucidate the underlying mechanisms of tax evasion (Tasks 1 and 3) and (b) innovate, proposing new perspectives to study tax evasion, both by the conjugation of variables in different levels of analysis (Task 2) and through exploratory experimental studies with new variables (Task 4). These four main tasks were developed to address what we consider fundamental themes in the research on tax evasion: Task 1) qualitative analysis of the representations about tax and tax evasion in focus groups with participants from the 5 NUTS, exploring lay perceptions about taxation concepts, causes and forms of intervention on tax evasion; Task 2) national representative survey of the attitudes toward tax evasion ("tax morale") and their relationship with official fraud data at the regional and national levels; Task 3) temporal analysis of the association between individual, economic and social factors with the accuracy of tax returns in the last 5 years; and Task 4) experimental studies that test real tax evasion behaviours in controlled situations that manipulate specific forms of penalty, reward and morality.

Hitherto, research has only taken fragmented approaches to the subject of tax evasion. Sociology, Economics, Law and Psychology have been working fragmentally with no interdisciplinary approach. This project aims to achieve an integrated perspective, analysing the validity of economic theory and expected utility predictions to understand tax evasion, combined and/ or improved by psychosocial contributions to inform more effectively legislators in tax and fiscal policy. This enterprise is an innovative and pioneer work in Economic Sociology in Portugal and intends to fill an academic gap in the research about the psychological and social facets of tax evasion, with the ultimate purpose to prompt the awareness of government institutions regarding the benefits to share the concerns of public policy and economic regulation with sociological research partners.