The chord-scale system is a method of matching, from a list of possible chords, a list of possible scales. The system has been widely used since the 1970s and is "generally accepted in the jazz world today". The system is an example of the difference between the treatment of dissonance in jazz and classical harmony: "Classical treats all notes that don't belong to the chord...as potential dissonances to be resolved...Non-classical harmony just tells you which note in the scale to [potentially] avoid..., meaning that all the others are okay".