The aim of the paper is to analyze three types of leaves connected with having small children in Poland as measures of public policy. In details logic of intervention for those measures will be analyzed. In particular I am going to analyse the maternity leave, paternity leave and parental leave . My research design is based on theory of intervention and theory driven evaluation (Chen 2005; Donaldson 2007; Pawson 2002; Petrosino et al. 2000, Górniak 2007; Ledzion et al. 2009; Olejniczak 2009). Those concepts treat each programme, project or a particular measure as a theory. It assumes that basing on particular resources and actions it will be possible to achieve expected permanent change. The theory of intervention consists of three parts: base theory, implementation theory and the theory of change. To meet the aim of the article for each measure (maternity/paternity/parental leave) I will reconstruct the base theory, implementation theory and the theory of change in two versions – as planned and real models. The differences of both models will be analyzed.