Voting Age Population Demographics

Election  campaign strategies and decision-making … in congressional district, state legislative district and wide-ranging other elections, the question arises “what are the characteristics of the voting age population for neighborhoods throughout the district?”  Unless the election is not really contested, an understanding of voting age population demographics is essential to successful campaign planning and decision-making.  The most effective and winning campaign messages require knowledge of voter demographics.  This section reviews availability and use of Citizen Voting Age Population (CVAP) demographics by census tract and congressional district.

Data to Meet Voting Rights Act Needs
The Voting Rights Act prohibits development of voting districts that discriminate against potential voters on the basis of race and/or language/minority status. To examine how voting districts comply with the Voting Rights Act requires data on the Citizen Voting Age Population (CVAP) by race/origin for small geographic areas. The ACS 2011 5-year CVAP special tabulation provides these estimates for census tracts and block groups.

Scope of Subject Matter & Interactive Data Access
The scope of the CVAP subject matter is focused on total number of United States citizens for the geographic area total number of United States citizens 18 years of age or older for the geographic area, each cross-classified by several race/ethnicity groups. The estimates for the number of citizens and voting age population for each of the race/ethnicity groups is provided by census tract in this interactive table (click link to view). A list of the items/columns is presented below the table on that page.

Relating Census Tracts to Congressional Districts and Other Areas
The interactive table shows a row for each census tract in the U.S.  The second and third columns show the corresponding 113th Congressional District.  The graphic shown below illustrates how to associate census tracts with California 113th Congressional District 39.  California is selected.  The table now shows only California census tracts.  Click the CD column header and navigate to CD 39.  The first row in the table below, in CA-39, shows a Census 2010 population of 7,955.  The ACS 2011 5 year estimates include: total population 7,763, total citizens 5,220 and total voting age citizens 2,855.  Similar attributes by race/ethnicity can be viewed in columns further to right (requires scroll).

cvaptable39

Visual Analysis of CVAP Demographic Patterns
Using GIS tools, the CVAP demographics can be used in mapping applications to reveal potential Voting Rights Act non-compliance in the structuring of voting districts.  GIS tools can similarly be used to examine patterns of CVAP demographics of census tracts/neighborhood areas across congressional districts, state legislative districts — or any other political/statistical geography.

Percent Asian CVAP by Census Tract — Los Angeles County Area
The graphic presented below shows patterns of percent Asian CVAP population by census tract in the Los Angeles area.  Asian is used to illustrate, other race/origin groups could be used.
cvap_asian_la
Click the graphic or this link for a larger view and related details.

113th Congressional Districts are shown with brown boundaries and CD number as yellow label.  Green patterns show different percentage intervals of percent Asian citizen voting age population by census tract (see highlighted legend in panel at left of map).  The identify tool (see pointer) used to display mini-profile of data for a selected census tract. Profile for tract 06-037-408703 located in 113th Congressional District 39 shows the estimate of Asian citizen voting age population (3,235) in this tract in context of other citizen and voting age data.

Zoom-in for More Detail — Adding Voting Districts
The next graphic shows a zoom-in to the tract area profiled in the above view. This view has the added layers of Voting Districts 2010 (red bold boundaries) and roads/streets.  Using this view it is possible to examine the relationships between the voting districts and census tracts (green pattern; black boundary).
cvap_asian_la2Click the graphic or this link for a larger view and related details.

Next Steps
In summary, characteristics of the voting age population are not available from Census 2010, but they are available at the census tract and block group levels from the CVAP ACS 2007-2011 special tabulation.  What about updates?  2012 CVAP estimates can be developed for Public Use Microdata Areas (PUMAs) by using the 2012 ACS Public Use Microdata Sample (PUMS).  PUMAs are generally groups of contiguous census tracts and must be 100,000 or more total population.  Since congressional districts are around 650,000 population, CVAP estimates could be developed that typically subdivide congressional districts by six or more PUMAs.  Los Angeles County, for example, contains 69 PUMAs.  2012 CVAP estimates could be developed for each of these PUMAs.

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