The effectiveness of human resource management can be analyzed at different levels. Some conducted studies
and researches focus on human resource management activities, while other analysis are relative to human
resource system as a whole. Lepak and colleagues (2004) believe that there are three levels in the analysis of
human resource system and considering these three levels seems to be very important for the understanding of
human resource management. These three levels and the way of their influence on each other have been shown
in figure (1).