Tracking Residential Growth With Microgrids

Scan/US Microgrids are square grids on the map, ranging from 1/16 square mile to 1 square mile.

Each Microgrid is a data container, holding population characteristics or other demographic data for that small area.

There are three sizes of Microgrid, determined by household density in an area.

Overall, approximately 2.5 million grids cover ONLY the populated areas of the United States. Demographic data is provided for each grid.

Microgrids make it possible for the software to calculate instant data summaries for rings, polygons, and drivetime contours.

Note: although 2010 was used as the analysis year for this study of Microgrids, Microgrids are updated annually, to reflect local changes in population.

We should also note that, although this study shows how Microgrids are better than Census Blockgroups for doing demographic analysis, all Scan/US Subscriptions do include Census Blockgroups with demographic data (and Census blocks and data are available as well), so if you have a Scan/US Subscription, you can do the comparison yourself, in any study area where you require it.

This three-part description shows how Microgrids are better.

  • First we present an overview
  • Second, in a more detailed look, we compare the Microgrid view of households on the ground , compared with the BG/Block depiction.
  • Finally we discuss one grid in detail.

1. The Study Area

Our 'study area' is a four block-group area in Santa Clarita, CA. This area illustrates how Scan/US shows change with its proprietary Microgrid geography.

As of 2000, US Census records 12 households in these four block groups. The Scan/US 2010 mid-year estimates show 2,835 households in residence, 90% of them new since 2005.

Four Census block-groups showing streets based on TIGER 2009 streets

A 2009 satellite image shows the extent of development that is revealed in the Scan/US 2010 estimates. (Google Earth photo)
This table summarizes the residential development in this 1.64 square mile area between 2000 and 2010.

2. Zooming in to the Neighborhood: Microgrids and Zip+4s and their relation to data

Using Zip+4 segment points, Scan/US tracks the placement of residential change more accurately than Census block groups or Census blocks.

Zip+4 segments are the basic units of the postal delivery system. Scan/US Microgrid cartography, summarizing data from Zip+4 segments, brings residential change into focus at the resolution of 1/16th of a square mile.

The study area contains 4 block groups, 12 blocks, 25 Microgrids and 274 Zip+4 segments. Residential saturation data (“drop counts”) for Zip+4s provide the data points for distributing block group estimates of household counts. How is this done?

First the drop counts of the blocks within a block group are normalized and used as weights to distribute the block group’s updated demographics to the blocks. The resulting detailed demographics for the blocks are then rebalanced to conform to the parent block group’s demographic profile. The distribution of the balanced block updates to the Microgrids is accomplished by using the current Zip+4 drop counts to calculate the proportion of block demographics that are to be assigned to the overlapping grids.

The Microgrid highlighted on the map derives all of its characteristics from one block but the Microgrid overlay of the study area shows that, in many cases, multiple blocks and block groups contribute to a particular grid’s demographic profile.

Scan/US Microgrids (blue grid) and Zip+4 segments (purple diamonds) superimposed on Census 2000 block groups

3. Focus on Microgrid 34118/2734.34

This grid contains the 16 Zip+4s listed below, along with their April 2010 “Drop Counts”.

The Zip+4 drop counts indicate where, how much and what type of development exists right down to a specific address range on a street.

The table below shows the four separate counts that are available for each Zip+4: single family (Napt), multi-family (Apt), business (Bus) and seasonal (Seas). These drop counts tell us that this Microgrid neighborhood is made up of exclusively single family dwellings.

The satellite photo below shows the 16 Zip+4s overlaid by the grid. (The image was created using Scan/US “Locate in Google Earth,” a standard feature of the Scan/US software).

The 16 Zip+4 markers on the image pinpoint the housing associated with the drop counts. The “TotRes” drop count approximates “total housing units” not “occupied housing units” or households. A cursory rooftop count of the housing seen in this satellite image of the grid comes to 120 housing units (as of the date of the image) compared to the “TotRes” counts of grid total of 170. The Scan/US 2010 balanced estimate of total housing units in the grid is 108 units.

ZIP+4 code TotRes Napt Apt Bus Seas
91354-1848 8 8 0 0 0
91354-1850 16 16 0 0 0
91354-1854 18 18 0 0 0
91354-1856 6 6 0 0 0
91354-1857 11 11 0 0 0
91354-1860 6 6 0 0 0
91354=1861 6 6 0 0 0
91354-1868 18 18 0 0 0
91354-1872 14 14 0 0 0
91354-1876 6 6 0 0 0
91354-1878 11 11 0 0 0
91354-1879 13 13 0 0 0
91354-1887 8 8 0 0 0
91354-4930 6 6 0 0 0
91354-4931 6 6 0 0 0
91354-4935 17 17 0 0 0
Grid totals 170 170 0 0 0

In conclusion: Scan/US Estimates

These numbers make this micro-neighborhood one that retailers would be glad to know is in their trade area. The neighborhood size of the Microgrid and the demographic information it contains make it the ideal unit of geography for supporting small area location based decisions.

Scan/US updates the Microgrid geography annually, adding new grids where Zip+4s have appeared for the first time. 196,117 grids were added this year to the 2010 Microgrid cartography for a total of 2,552,006 Microgrids covering the United States.

The Scan/US QuickLook for this Microgrid displays about eighteen 2010 demographic variables selected from approximately 1000 values that are estimated and projected for every object on each geographic layer.

This grid is roughly 1/16th of a square mile in size and is estimated to contain 99 households with an average size of 3.10 persons; median household income is $57,790, and an annual aggregate household income of $6,440,000.

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