Methodology

	*DemographicReports.com*

Call us at
1(949)365-0125

Methodology
When working with demographic data, nothing is more important than the quality of the data being presented. Since the census is only taken every 10 years, update methodology is a very important factor when dealing with demographics. That is why DecisionWhere has chosen to utilize demographic updates developed by Scan/US, Inc. Their current-year estimates and five-year projections are built using a series of complex models they have developed and refined over the past four censuses!

2007/2012 Update
The 2007/2012 demographic update incorporates the most current controls from Census 2000 and then utilizes TIGER segment address ranges, United States Postal Service (USPS) carrier route drop counts, ADVO ZIP+4 deliverable household counts, and USPS ZIP+4 inventory for the current time period to estimate current year household counts. The integration of these source files through geocoding results in a derived household count for census blocks for the current time period. This block level update is then allocated to block faces of street segments within blocks and distributed to microgrids using block face points.

Fortunately, the critical elements of this grid definition process are continually updated. New TIGER address segments, new ZIP+4s, growth in the ADVO & USPS delivery counts are all indicators of residential growth and more significantly, they tell you how much growth and where it is occurring. By annually merging these sources and rerunning the grid definition process, residential growth can be tracked at the block face level on a continual basis providing highly accurate current year estimates and making MicroGrids an extremely accurate system of geography for data retrieval and detailed thematic mapping.

The Microgid Advantage
The MicroGrid is a revolutionary geography, developed by Scan/US, that displays demographic characteristics of an area down to 1/16 of a square mile. Derived from the 2000 Census block level data, the current MicroGrid layer is made up of 1.9 million grids. When compared to the Census block group geography of only 209,000 block groups, or the residential ZIP code geography of 29,900 ZIP codes, you can understand how much more information MicroGrids convey.

Microgrids convey information by their size & shape.

Notice the detail of the population distribution within a single zip code area.

Grid shape – rectangular – provides a visual regularity that helps you clearly see the information hidden in the population distribution patterns. The distortion resulting from irregularly shaped features such as tracts and zip codes is avoided with microgrids.

Grid Size – small, medium and large – give you an immediate estimation of the population density. When the population of a large grid (1 sq. mi.) exceeds 600 households, the grid is split into medium grids. If a medium grid (1/4 sq. mi.) has more than 150 households, the grid is split into the small grids (1/16 sq. mi.). Generally, the small 1/16 mile grids represent the densest urban areas. The medium grids, ¼ mile square, indicate small metro areas or isolated communities. The large 1 mile square grid suggests rural or non-urban areas with low population density.

Absence of Grids – indicates the absence of residential population. These grid-less areas could represent open wilderness areas, parks, airports or industrial/commercial developments.