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Methodology

How we source, calculate, and visualize demographic data

Data Sources

U.S. Census Bureau

All demographic data comes from the American Community Survey (ACS) 5-Year Estimates (2022). This is the most comprehensive and reliable source for neighborhood-level demographic information in the United States.

TIGER/Line Shapefiles

Census tract boundaries are obtained from Census TIGER/Line shapefiles, which define the geographic areas for which demographic data is collected. Each tract typically contains 1,200-8,000 people.

Population Growth Data

Historical population data uses TIGER Crosswalk files to map 2010 Census tract boundaries to 2020 boundaries, ensuring accurate growth calculations despite changing geographic definitions.

Metrics Tracked

Economic Indicators

  • • Median Household Income
  • • Median Home Value
  • • Poverty Rate
  • • Employment Rate

Population Metrics

  • • Population Density (per sq mi)
  • • Population Growth 2010-2020
  • • Population Growth ACS 5-Year

Education & Housing

  • • Bachelor's Degree or Higher %
  • • Renter-Occupied Housing %

Scoring Methodology

1. Percentile-Based Normalization

To handle extreme outliers, we use the 5th and 95th percentiles as minimum and maximum values instead of absolute min/max. This prevents a single anomalous tract from skewing the entire color scale.

Min = 5th percentile | Max = 95th percentile

2. Individual Metric Scoring (1-10 Scale)

Each metric is scored from 1 (worst) to 10 (best) based on where it falls within the percentile range. Negative metrics like poverty rate are inverted so lower values score higher.

Score = 1 + ((value - min) / (max - min)) × 9

3. Weighted Average Calculation

Tracts are scored only on available data—missing metrics don't penalize the score. You can adjust each metric's weight using the multiplier sliders (×0.5 to ×1.5). The final score is a weighted average:

Final Score = Σ(score × multiplier) / Σ(multiplier)

4. Null Data Handling

Tracts with no enabled metrics are colored gray. This visually distinguishes areas without data from areas with poor scores.

Color Visualization

Decile-Based Color Scale

Final scores are divided into 10 equal groups (deciles), each assigned a color from red (lowest) to green (highest). This ensures the full color spectrum is used even when score ranges are narrow.

Lowest 10%
Middle 50%
Top 10%

Dynamic Radius Filtering

When you search for a location, only census tracts within your selected radius (5-100 miles) are scored and colored. This creates a localized comparison—a tract scoring 10/10 is in the top 10% of nearby areas, not nationwide.

Important: Scores Are Relative, Not Absolute

Because scoring is relative to your search radius, a "green" (high-scoring) tract in Chicago may not be directly comparable to a "green" tract in Atlanta. Each location is scored against its local market, not a national baseline. This means the tool excels at identifying the best neighborhoods within a specific metro area, but cross-market comparisons should be made cautiously by reviewing the underlying demographic data rather than relying solely on colors.

Future Enhancement: We plan to add a nationwide scoring mode that will enable direct comparisons across different metropolitan areas.

Radius Statistics

The 1-mile, 3-mile, and 5-mile radius statistics are population-weighted averages of all census tracts whose centroids fall within the specified distance from your selected location.

Avg Income = Σ(tract income × tract population) / Σ(tract population)

This weighting ensures larger tracts don't get disproportionate influence in the averages.

Limitations & Considerations

  • Data Lag: ACS 5-Year estimates represent averages over 2018-2022, so very recent changes may not be reflected.
  • Geographic Granularity: Census tracts vary in size and can mask intra-neighborhood variation.
  • Missing Data: Some tracts, especially low-population areas, may have incomplete demographic data.
  • Scoring Subjectivity: The "best" neighborhoods depend on your priorities—adjust metric weights to match your preferences.

Last Updated: December 2024 | Data Source: U.S. Census Bureau ACS 2022 5-Year Estimates