The Coastal Bays Health Index, for each region, averages (i.e., equally weights) the six indicators used into a single overarching index score. This score evenly combines all six indicators (chlorophyll a, dissolved oxygen, total nitrogen, total phosphorus, seagrasses, and hard clam) into an overall assessment of health for each region. Each region's score is then area-weighted and averaged to produce the overall Coastal Bays grade.