Methodology

Green Grade

The Green Grade is determined by a continuous 0–100 score that combines four environmental indicators. Each indicator is mapped to a 0–1 component score using linear interpolation between defined cutoffs, then multiplied by its weight. The weighted components sum directly to the final 0–100 score.

• Lead in Drinking Water (weight: 40%): Lead concentration in parts per billion (ppb) from the school's public water system. Full credit at 0 ppb; no credit at ≥ 15 ppb. Lower is better.
• Air Quality Index (weight: 40%): County-level median AQI. Full credit at ≤ 50; no credit at ≥ 101. Lower is better.
• Electric School Buses (weight: 10%): Share of the district's bus fleet that is electric. No credit at 0%; full credit at 100% electric.
• Tree Canopy Coverage (weight: 10%): Percentage of school grounds covered by tree canopy. No credit at 0%; full credit at ≥ 60% coverage.

The resulting 0–100 score is assigned a letter grade (A+ through F) and a national percentile rank showing how the school compares to all scored schools in the dataset. Schools missing any required indicator are not scored.

Actionability Grade

The Actionability Grade combines six factors that indicate how ready a school or district might be for climate improvements: district financial resources, community climate opinions, policy support, and how much room for improvement exists. Each factor is standardized and then weighted:

• District Total Revenue (log) (weight 2.0): Log of total district revenue, indicating financial resources
• Citizens Should Do More (weight 0.75): Percentage of district residents who believe citizens should do more about climate change
• Support Renewable Energy (weight 0.75): Percentage of district residents who support renewable energy on public land
• Local Officials Should Do More (weight 0.75): Percentage of district residents who think local officials should do more
• Policy Impact (weight 1.5): Measure of state-level policy support for climate action
• Green Grade Difference (weight -1.0): Difference between school green score and district average (negative weight because lower relative scores indicate more room for improvement)

The weighted sum creates an actionability index, which is converted to a 0–100 national percentile rank and then mapped to a letter grade (A+ through F). The 13 grade bands are equally spaced across the percentile range — each covering roughly 7.7 percentile points — so that each grade is assigned to approximately the same share of schools nationwide.