ItemInformal Employment in Ukraine and European Union Transition Countries : PhD thesis, July 5, 2018 for achieving the degree of PhD scholar of University Paris-Est, discipline: economics(2018) Nezhyvenko, Oksana; Adair, PhilippeThis thesis contributes to a better understanding of the nature of informal employment in transition countries in particular. We present the results of the first Ukrainian Undeclared Work Survey and compare its results with the Eurobarometer-2013. Undeclared work and envelope wages prevail in Ukraine and the EU, and the reasons for working undeclared are mostly driven by necessity. Second, we investigate the wage differentials and determinants in a set of nine EU transition economies with respect to informal employment, and the gender disparities of wage distribution. The significant wage penalty for informal employment proves always higher for females than for males. Regardless gender, individual and job characteristics explain more than half of wage penalty. A wage decomposition suggests that the difference between formal and informal employees is better explained on the demand side of the firms than on the supply-side of the workers. Third, we focus attention on informal employment in Ukraine. The division of all the employed population (formal employees, formal self-employed, informal employees and informal self-employed) suggests strong heterogeneity between these four categories and proves the human capital theory to be robust in as much as educational attainment is a major explanatory factor for formal employees only. Last, we examine prostitution as an informal activity from the demand side and the supply side. We produce four estimates of the number of sex workers in the EU and Ukraine. Our lower bound estimate from the data on HIV prevalence suggests that there are circa 542,000 prostitutes in the EU and 33,000 in Ukraine as of 2010. The legalisation of brothels is positively correlated in all our models with three Estimates in the EU-28 and Ukraine.