PL
The methodology of enterprises' competitiveness studies plays a leading role in their efficiency enhancing. In the presented paper, there have been recognized the premises that affect enterprises' competitiveness. Among other premises, exchangeable value, judging choice and services exploitation have been ranked as the most significant ones. Taking into account the difference between the feature of a whole system and the feature of each system part, one should employ system driving standard in assessing enterprise's competitive advantage. The peculiarities of system may be explored to find the sources of competitive advantage on the basis of visible measures as well as invisible but gradable measures. First conception formulated in the paper pertains to the synthetic evaluation of competitive advantage on the basis of alternative cost concept. Another conception relates to the process of competitive advantage assessing that is based on the relativity of specific factors. Mentioned factors determine competitors' supply and demand.