Figure 5

Character of different districts in the d-R plane.
(a) The positive area of Ochiai (district I, II, IV and V) and Poisson (district I and III), cases below the cutoff-line (green for Ochiai and blue for Poisson) have larger score than the cutoff. (b) The uneven distribution of cases in the d-R plane. (c) The PPV of different districts (Ave_within and Ave_beyond: are the average PPV for the district within and beyond the boundary line respectively). (d) The three meaningful areas in the d-R plane, i.e. the district beyond the boundary, the low-quality district (red shadow) and the high-quality district (light blue shadow).