Each redistricting dataset merges the electoral data the SWDB collected and processed over the preceding decade with the most current census data (PL94-171). The result is a census block level dataset that allows for longitudinal analysis of electoral data over time on the same unit of analysis. Electoral data consist of the Statements of Vote (SOV) and Statements of Registration (SOR) for each statewide election. These data are collected from the Registrars of Voters for each of the 58 California counties with each election.
The SWDB collects the Statement of Vote and the Statement of Registration along with various geography files from each of the 58 counties for every statewide election. The Statement of Vote is a precinct level dataset and precincts in California change frequently between elections. The goal of the SWDB is to make election data available that can be compared over time, on the same unit of analysis – a precinct, a census block or a census tract.
This diagram illustrates the naming scheme for conversion files in the SWDB.
These conversion files are available here.
RG = Original Registration Precincts (designated by County Registrar)
RR = Registration Precincts (geographic unit constructed for statistical merging purposes by SWDB)
SV = Original Voting Precincts (designated by County Registrar)
SR = Consolidated Precinct (geographic unit constructed for statistical merging purposes by SWDB)
1990 City = City Area (designated by US Census Department)
1990 Census Blocks = Census Blocks (designated by US Census Department)
1990 Census Tracts = Census Tracts (designated by US Census Department)
"Cross Election" = moving between election years, i.e. from 1994 geography to 1996 geography
Naming Convention: "origin unit"-"election and year" -"destination unit"_"coverage".CNV
"##" = wildcard symbol
This diagram illustrates the relationship between different types of precincts you may find in our datasets.
RG = Original Registration Precincts (created by County Registrar of Voters)
RR = Registration Precincts (created as part of the SWDB merging process)
SV = Original Voting Precincts (see 1)
SR = Consolidated Precinct (see 2)
These are links to pages explaining "Geographic Hierarchy for the 1990 Decennial Census" and "Small Area Census Geography in the 1990 Census." These pages were drawn from the Geographic Area Reference Manual, Chapter 2, pages 7 and 9. This document is available on the census Web site at www.census.gov.
Overall precinct relationship
The counties have registration (RG) and Voting or consolidated (SV) precincts as well as ballot groups for each election. Registration statistics are reported by RG precinct and election results are reported by SV precinct and/or ballot group (ABSPREC). The counties also report the grouping of RG precincts in SV precinct and Ballot group (although the ballot group reporting is inconsistent and incomplete).
The counties also provide maps or gis files showing registration precinct geography, but the geographic representations do not necessarily match the RG precincts for one or more of the following reasons.
We create map precincts (MPREC) to reflect the geography as consistently as possible. RR precincts are aggregations of RG precinct (tabular data) into MPRECs (geographic). (Generally speaking Map Precincts are RR precs)
Because the resulting RR precincts may include RG precincts that are consolidated into different SV precincts we create a geographic consolidation know variously as SS or SR precincts to contain whole RR and SV precincts.
The SR precincts are the level at which precinct election results can be given a geographic representation.
We would love to help. Please leave us a message and we will get right back to you: