Thats the thing with Power Levels... Naruto has none... Bleach and Dragon Ball Z have a direct system for tracking power levels. And those with the higher power level often win.
In Naruto it comes down to the situation, experience and strategy. With an added hint of luck... Well actually luck is part of the situation. For example in Naruto the most basic two things you would assume represent strength are how much Chakra one has an there title. And to a point that is true but the measure of chakra along has almost never been used as a plot means to determine who should win in a fight. Titles used to play a more important role back in the time were we only knew so many characters and the genins we knew were new genins so the strength between them and the teachers or other higher ranked ninja was obvious. But in reality the title does not mean much at all.