The article presents an analysis of the real role of the complementarity principle and the reasons why immi-gration law is still based on this principle. The basic assumptions of the state’s attitude towards labour im-migration were set out in a period when this kind of immigration to Poland was at a much smaller scale than currently. First and foremost, one of the basic premises is the complementarity of labour immigration (com-plementarity principle) with the labour market test as an element of the procedures, although with some exceptions. The mechanism of controlling the complementarity is obligatory and preventive. The current economic situation in Poland, including the conditions for the functioning of immigration law, is very differ-ent from the reality of that time. In view of growing shortages of Polish employees on the labour market one can doubt whether preventive enforcement of complementarity by law is needed. The complementarity of labour immigration to Poland is a socio-economic fact and legal guarantees to ensure this result seem ob-solete. There are strong arguments to consider that opportunistic political motivations are the main reason against the rationalisation of legal regulations concerning immigration of workers. The complementarity principle has become a facade of restrictive immigration law, while allowing for its use in a way that ensures the access of immigrants to the labour market.

This study aims at identifying determinants of health related quality of life in Poland, and in particular at verifying whether health domains are complements or substitutes and what the impact of heterogeneity of population on the health state valuation is. The paper uses data in panel structure coming from a survey conducted in Poland and consisting of 6700 valuations (after data cleaning) of EQ-5D health states with time trade-off method. Several econometric models are built in order to detect the impact of complementarity and heterogeneity. Random effects models as well as random parameters models estimated using Bayesian approach are used. The results show that health domains are complementary goods. Especially the lack of pain/discomfort is a complement to other health domains. Demographic factors influence how health state change impacts utility. These factors encompass sex, education, respondent’s health state and even belief in life after death.