Problems in assessing the expression of illegal work from the aspects of economic activity and policy in the EU

Not only the size but also the composition of shadow economy and undeclared work are different in the EU Member States. The illegal work is apparent in sectors, where there is a high need of physical work, not requiring high qualification or competence, which is often associated with the second job that is performed in order to increase the income in an unofficial way, when the employers pay the whole or part of the salary illegally in order to avoid taxes; the employees work based on the contracts that are filled in an incorrect manner or without them, as well as when the overtime is not recorded, etc. The analysis of a scientific literature shows that the change and the situation in the market of the illegal work are assessed basing them on different methodological approaches, based on unequal criteria, the reformation of the labour market in different countries is implemented in different direction/uneven track. This is related not only with different economic and social status of the countries, demographical changes, legal basis, but also with different policy, views and assessment indicators. Objectives of the research: 1) considering the variety of theoretical concepts for illegal work, to specify the changes in the definition of illegal work in the individual EU countries; 2) to identify the assessment methodologies of illegal work and changes of its extent; 3) to review the extents of illegal work in the EU countries and Lithuania, by providing measures for reducing it.