Fig. 3. LISA cluster maps for block group proportions of children with elevated lead levels (BLL ≥ 5 µg/dL).

Block groups designated as high-high or low-low mean that the block group has high (or low) BLL and is neighbored by other block groups with high (or low) BLL. A high-low or low-high designation means that, respectively, a high BLL group is neighbored by low BLL block groups or a low BLL group is neighbored by high BLL block groups. High-high (hot-spotting) and low-low (cool-spotting) zones show areas of clustering, while high-low and low-high zones highlight outliers in the data.