String Edit-Distance vs. tree Edit-Distance. The 60 family members of the Lysine family were compared against each other using string and tree ED. The X coordinate of each dot is its tree ED score, and the Y coordinate is its string ED. The correlation coefficient is 0.92, and only a few dots fall far from the main diagonal. Also note that the correlation coefficient of pairs having a tree ED less than or equal to ten is 0.97.