Learn how SparkMap calculates ZIP code, city, and custom area data.
★ Useful for Premium Subscribers
ZIP Code Calculations
The ZIP data source depends on the availability of the data at different geographic levels. For data that are available at the ZIP code level (really, ZIP Code Tabulation Area level), like measures from the American Community Survey, we provide the ZCTA estimates. Address-level data are also aggregated to the ZIP codes.
For data that are available at the Census tract and County level (for example, air quality data), the ZIP estimates are population-weighted averages based on the intersection of tracts and ZIP Codes. We also provide some county-level data (cancer, mortality estimates), calculated at the ZIP code level. These are also population-weighted calculations based on the larger county data. In our indicator reports, the source geography column will tell you the smallest level of geographic detail available for an indicator.
As a Premium Annual subscriber, you can easily generate a ZIP code report. As a Premium subscriber you can also generate a report for specific ZIP codes by using the Pick From Map feature. Note: the Pick From Map feature will aggregate your assessment location and will not provide individual information for multiple ZIP codes in a chosen area
City-level Data Calculations
As a Premium subscriber, you can also select cities using the Pick From Map feature in the Community Assessment. Some of our sources have city-level data (ACS, BRFSS, Census). For others, we use the population-weighting approach, based on the geographic level of the underlying data. If the underlying unit is a census tract, the data for a city will proportionally reflect the tract or tracts which intersect the city boundary. If the underlying data is a county and the city falls entirely within the county, the city record will show the same data for the county (the percentages will be identical, the counts will be population weighted).
Draw My Area
When you select Draw My Area and create a custom area on SparkMap, we use population-weighted allocations, currently based on the 2010 Census data. For more information on how a particular indicator is calculated for a small geography, visit the Data Source information in the report (“Show more details”).