Missouri: Comparison of Registered Voter Counts to Census Voting Age Population

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By Earl F Glynn | Franklin Center

A comparison of US Census voting age population data in Missouri to voter registration data shows a number of Missouri counties have bloated voter registration lists.

Charts by county for the years 2000 to 2012 show how counties are maintaining their voter lists.

Voter fraud potential is higher in the Missouri counties that have poorly maintained lists, such as Reynolds County that has more voters than census population, or  St. Louis County and other counties with 95+% voter registration when compared to census population.

This is not a new problem in Missouri.  Reynolds County has had more voters than census voting age population for more than a decade.

About 10.7% of Missouri’s 4.1 million voters are “inactive” usually with unknown mailing addresses.  The 436,000 “inactive” voters are another measure of voter bloat of the state list.

There is higher voter fraud potential in areas of unmanaged voter lists and areas of high voter list bloat measured by inactive voters.


Yearly US Census population estimates for Missouri counties were extracted for the years 2000 to 2011.

Active and inactive voter registration totals were extracted from the Missouri Secretary of State’s web site for November general elections in 2000, 2002, 2004, 2006, 2008 and 2010.

Additional active and inactive voter registration counts by county were obtained directly from files of Missouri voters obtained at 12 different times from 2004 to 2012.

The census and voter registration data were plotted for easy visual comparison of any particular year or trends over time.

Results:  County Charts

View the PDF with a chart for each Missouri County comparing US Census Voting Age Population to Registered Voter Counts
[116 pages:  114 counties, City of St. Louis, state total]

(click on graphic to view PDF)

General comments about all charts:

  • The black line represents the total county population from the Census 2000 and the Census 2010 enumeration and census estimates for other years.
  • The blue line represents the census voting age population counts or estimates, those 18 years or older.
  • The voter registration points in red represent total registration values (Active + Inactive) from either the Secretary of State’s online reports or from voter files.
  • The points in green represent only the Active voters.  The difference between Active and Total registration, the Inactive voters, is a measure of voter bloat.

NOTE: US Census estimates are not as accurate for smaller counties on a relative basis.  See Limitations in US Census Voting Age Population.

Selected Missouri Counties

Reynolds County:  Over a decade of problems

(click on image to enlarge)

From roughly2000 until 2008 Reynolds County had more voters than it did population of all ages.

Since 2010 Reynolds County has total registration above 100% of voting age residents.  By the numbers nearly all people of voting age in Reynolds County are “active” voters.

Pulaski County:  Low voter registration near military base

(click on image to enlarge)

Pulaski County is the home of the US Army’s Fort Leonard Wood.

While the census population estimates were relatively flat from 2002 to 2009, the 2010 census numbers show likely under counting during the previous years.

Almost everyone is registered to vote in St. Louis County?

(click on image to enlarge)

For years St. Louis County, the most populous in Missouri, has total registration just under 100% of voting age population.

Other counties with ~95% or higher registration of voting age population from their charts include:  Atchison, Barton, Cass, Chariton, Dade, Douglas, Gentry, Holt, Howard, Lafayette, Ozark, Putnam, Shelby, Sullivan.

Details of Technical Approach

Let’s first review the needed raw data files and then discuss the processing to create the charts above.

Raw Data:  Missouri Voter Registration Statistics

The Missouri Secretary of State publishes a “Voter Turnout Report” in even-numbered years reflecting the November general election.

Unfortunately, for those wanting to analyze the data, the turnout reports are in a PDF format.  The PDF files have columns for Registered Voters, Active Voters, Inactive Voters and some other data.

For this analysis we want the total Registered Voters and the Active Voters from the PDF files. (Active Voters + Inactive Voters = Registered Voters.)

These turnout report PDFs were downloaded for years 2000, 2002, 2004, 2006, 2008, 2010 and converted to Excel files using the program Able2Extract Professional.  After the automatic Able2Extract conversion some manual cleanup of the files was necessary so the file could be read by an R program.

The R script combine-ODBC.R used R’s ODBC package to read the Excel files and create two files to be used as inputs later:

In addition to combining the data from the six files into two separate files for “total” and “active” voters, combine-ODBC.R standardized the spelling of counties to match that used by the US Census.

The US Census gives estimates for both St. Louis City and St. Louis County, and the Missouri Secretary of State maintains them as separate voting districts.

Missouri treats Kansas City as a separate voting district from Jackson County, but since the census does not give separate population estimates for Kansas City and the rest of Jackson County, Kansas City voter registration data were included with Jackson County values in this analysis.

Raw Data:  Missouri Voter Registration Files

I used several files of Missouri voter registration data to supplement the official statistics in general election years.

Kansas City, MO marked “no trespassing” on this “dangerous building” but two “inactive voters” using this address cast ballots in the MO Democratic House 40 primary contest decided by one vote in August 2010.

I had access to some older Missouri voter registration data, but Missouri Watchdog purchased registration data several times in 2010 and 2011 for analysis after a contested Missouri House race.

In August 2010 a Missouri Democratic House primary contest was decided by one vote even though Missouri Watchdog found several irregularities ignored by the courts including two “inactive” voters who cast ballots from the address of an abandoned house marked a “dangerous building” by Kansas City, MO.

In all I found 12 files of Missouri voter registration data for analysis that had been obtained from the Missouri Secretary of State from 2004 to 2012.  (Thanks to those who shared files over the years).

A separate R script produced counts of Active, Inactive and Total voters by county for each of the 12 voter registration files. An “active-inactive.csv” file recorded the statistical summary for each voter file.  [A future article will address producing statistical summaries of Missouri voter registration data.]

The script combine-text.R combined the separate files by year into summaries of total voters and active voters.

Similar to the two files produced summarizing the turnout election statistics, the summary of the voter files was reduced to two files:

Raw Data:  US Census Data for Missouri

The links below are to the raw online Missouri census data at the US Census site.

Annual Estimates of the Resident Population by Selected Age Groups and Sex for Missouri Counties:

The technical article US Census Voting Age Population gives details of extracting US Census data for all states, including Missouri, and plotting charts of that data.

Updated US Census county population estimates for July 1, 2012 are expected in April 2013.

R Program

After pre-processing the raw data described above, we can create charts showing US Census voting age population in Missouri and the number of registered voters by county.

Input files

Census files:

Voter registration summary files:

Processing Script:  Missouri-Voting-Age-Population-and-Registered-Voters.R

After reading voter registration data into data.frames (voters.total, voters.active, voter.file.total and voter.file.active) the script called function get.voting.age.census.data to read Missouri census data.

The census data was passed to the plot.county.population.charts function for plotting along with a “callback” function, plot.missouri.registration.

The plot.county.population.charts function plotted the census data and then used the plot.missouri.registration “callback” to plot the registration data on the same chart.

Output files


Census Continuity

Normally the US Census estimates from 2009 are fairly consistent with the actual US Census counts from 2010, but sometimes there are unexpected increases or decreases in population as a result of the census.

About half of Missouri counties saw a population increase of 0.3% to 4.4% between the 2009 population estimate and the actual 2010 census.

Two statistical “outliers” were St. Louis City that lost 10.5% from 2009 to 2010 and Pulaski County that gained 12.5%.

Voter Bloat (inactive voters)

In late March 2012 Missouri voter list bloat was slightly more than 436,000 voters, which is slightly down from 471,500 in 2010.

About 10.7% of Missouri’s 4.1 million voters were marked “inactive” by county clerks and election officials in March 2012, but the label should be “unknown address” or “voter list bloat.”

Mail cannot be delivered to the addresses of these inactive voters but these people can vote if they show up at the polls.

Missouri counties with low inactive voter rates:  Cedar (1.0%), Mississippi (1.2%), Caldwell (1.5%), Texas (1.6%).

Election jurisdiction/counties with high inactive voter rates:  Kansas City (21.4%), Boone (19.1%), Greene (17.4%), Howard (17.1%).

The voter bloat can be seen in the charts as the difference between the total registration and active voter counts.

A low percentage of inactive voters is not necessarily good since the federally-mandated process of removing a voter often involves a voter marked as “inactive” for several years.

County clerks responsible for maintaining voter registration lists often say look at only the “active” voters to measure how well a list is maintained.  But an “inactive voter” can still vote if they show up at the polls so they should be counted in voter totals.

According to the 2010 Statutory Overview Report from the US Election Assistance Commission, Missouri marks a voter as “inactive” for “no response to confirmation notice” from an election authority.

Maintenance of Voter Lists (comparison to census)

U.S. federal law (Help America Vote Act of 2002) limits how state and local officials may remove names from voting rolls. But even with hands tied by the federal government, there is wide diversity in how county clerks maintain voting lists.

The intent of the federal law was to maintain voters’ rights and the integrity of federal elections. But what safeguards are in place to maintain integrity of local elections when people with an unknown address vote in local elections?  When “inactive” voters cast ballots are they voting in the correct state and local districts?

The US Census voting age population estimates give an upper bound on what the actual voter registration should be in a state or county. When lists are not maintained by the county clerks and election officials the “bloat” can grow over time resulting in more voters registered than the census says are of voting age.

Observations from the county charts yield these estimates of registration as a percent of voting age population:

  • High RegistrationReynolds (105%), Dade (97%), Douglas (97%), Howard (97%), Putnam (97%), Shelby (97%),  Atchison (95%), Cass (95%), Chariton (95%), Gentry (95%), Holt (95%), Lafayette (95%), Ozark (95%), St. Louis (95%), Sullivan (95%)
  • Low Registration:  Pulaski (55%), DeKalb (62%), Nodaway (70%), Adair (75%), Barry (75%)


  • Reynolds County shows more voters than the US Census says are of voting age in that county and has had that problem for a decade.  Reynolds County has NEVER reported fewer people to vote than the census voting age population.
  • From 2000 to 2004 and briefly in 2009 Butler County had more voters than census voting age  population.
  • From 2000 till 2009 Carter County had more voters than census voting age population.
  • During much of 2010 Clark County had more voters than census voting age population.
  • From 2000 to 2005 Dade County had 100% or more of voting age population registered to vote.
  • From 2000 to 2009 Gentry County had about 100% of voting age population registered to vote.
  • Holt County had a problem with more registered voters than census voting age from 2000 to 2008.
  • From 2004 to 2008 Ozark County had 100+% of voting age population registered to vote.
  • For over a decade until a recent 2012 voter file, Putnam County had 100+% of voting age population registered to vote.
  • From 2000 to 2006 Schuyler County had more voters than census voting age population.
  • Shelby County has flirted with about 100% registration of voting age population from 2004 till 2010.  Even in 2012 the registration is about 97%.
  • All of the counties listed above in this comments section received a grade of “F” from Sunshine Review for transparency when the Missouri state average is a “B”.
  • Even if US Census estimates had been a bit higher for population, Worth County has had 100+% registration of voting age population from 2000 through 2009.  Sunshine Review gives Worth County an A+ for transparency now.

About 90% of Missouri’s voting age population is registered to vote.


Without safeguards in place an “inactive voter” list could be a tool for voter fraud, yet such lists are available as open records under Missouri Sunshine Law.

Missouri’s requirement to present an ID to vote is a good check and balance on the bloat in the voter lists.

Even with voter ID, bloated lists offer greater potential for voter fraud if committed by election officials since a name can be “borrowed” from the inactive list to cast a fraudulent vote.

Missouri voter lists in a number of counties invite additional scrutiny every year because of their poor maintenance in recent years.


  • 2010 Statutory Overview Report, US Election Assistance Commission, May 2011. [Gives definitions of active and inactive voters by state. See PDF pages 16-18]

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