Spark Map synthesizes data from three primary sources:

Opportunity Atlas From Harvard/Census Bureau, provides income mobility and incarceration rate estimates at the census-tract level. These measure the average outcomes of children who grew up in each neighborhood.
opportunityinsights.org

Child Opportunity Index 3.0 From diversitydatakids.org, a composite index measuring neighborhood opportunity across education, health/environment, and social/economic domains. Provides z-scores comparing each tract to the national distribution.
diversitydatakids.org

Census & ACS Tract boundaries come from the U.S. Census Bureau’s 2020 TIGER/Line shapefiles. Population estimates are from the American Community Survey (ACS) 5-year estimates.

💰 Income Mobility — The mean household income rank (percentile 0–1) for children who grew up in each tract, pooled across race and gender. Source: Opportunity Atlas (kfr_pooled_pooled_mean).

🎯 Opportunity Index — The overall Child Opportunity Index z-score (z_COI_nat), which combines 30+ indicators into a single national-normed score. Positive = above average, negative = below.

📚 Education — COI education domain z-score (z_ED_nat). Includes early childhood education centers, third-grade reading/math proficiency, high school graduation rates, AP course enrollment, and school poverty rates.

🏥 Health/Environment — COI health & environment domain z-score (z_HE_nat). Includes health insurance coverage, toxic exposure risk, air quality, access to healthy food, and green space.

👥 Social/Economic — COI social & economic domain z-score (z_SE_nat). Includes poverty rate, public assistance, employment, median household income, and housing vacancy.

⚖️ Incarceration — The mean incarceration rate for children who grew up in each tract. Source: Opportunity Atlas (jail_pooled_pooled_mean). Higher = worse outcomes.

A Mobility Desert is a census tract where children’s average income mobility is below 40th percentile (the 0.40 threshold on the Income Mobility lens). These are neighborhoods where, historically, children growing up there earned significantly less as adults compared to the national average. The threshold was chosen to identify the bottom tier of economic opportunity for advocacy purposes.

The Opportunity Atlas uses 2010 census tract geographies, while the COI 3.0 and our basemap use 2020 census tracts. We applied the official Census Bureau 2010-to-2020 crosswalk to map the Atlas data onto 2020 boundaries. When a 2010 tract was split into multiple 2020 tracts, the same value is assigned to each child tract. When multiple 2010 tracts merged, we use a population-weighted average. This achieves approximately 98% data coverage across Maryland’s ~1,400 tracts.

The gradient runs from red (worst outcomes) through yellow (middle) to green (best outcomes). For z-score lenses, the scale spans −1.5 to +1.5 standard deviations. For percentage lenses (Mobility, Incarceration), stops are set at meaningful policy thresholds. The incarceration lens reverses the colors since higher values represent worse outcomes.

Purple tracts are designated Special Locations, areas like airports, correctional facilities, or institutional campuses that lack meaningful residential census data. Since few or no people live in these tracts permanently, income mobility and opportunity scores are not applicable. We color them distinctly to avoid misinterpreting the absence of data as poor outcomes.

POI layers (Hospitals, Schools, Parks, Libraries, Stores) are sourced from OpenStreetMap exports filtered to Maryland. They are overlaid on top of the census tract data to show the relationship between community resources and opportunity scores. When you filter by county, POIs are automatically scoped to that county.

1. Use the Mobility Desert toggle to identify the most under-resourced tracts in your county.
2. Export the desert tracts as CSV for grant applications and policy briefs.
3. Switch between lenses to understand why a tract is struggling, is it education, health, or social/economic disadvantage?
4. Toggle POIs to see if the area lacks schools, libraries, or healthcare access.
5. Click on any tract for a detailed popup with the exact score and GEOID for citing in reports.