Census Self-Response Rates Mapped: 2000, 2010 and 2020
Published March 16, 2020
The Center for Urban Research at The Graduate Center, CUNY has updated its Census 2020 Hard to Count (HTC 2020) map with self-response trends from the past two decennial censuses, to provide historical context as stakeholders fine-tune their Get Out the Count (GOTC) plans and participate in the U.S. Census Bureau’s Response Rate Challenge.
The analysis below provides background for this information and the importance of self-responding to the decennial census, especially as the count takes place during the coronavirus pandemic.
Self-responding is the best and least-expensive way for the Census Bureau to collect information. But self-responding has taken on heightened prominence during the coronavirus outbreak. Self-responding means you will avoid a knock at your door from a census enumerator. And because of the options the Census Bureau has provided for self-responding — online, by phone, or by mail — every household should strive to respond to the 2020 Census on their own.
State Trends from 2000 to 2010
The U.S. Census Bureau’s Response Rate Map displays self-response rates from the 2010 Census as an incentive for communities across the country to surpass those rates in 2020. But to provide context for the 2010 rates and show which areas improved or not from 2000 to 2010, the Center for Urban Research has mapped and analyzed the 2000 and 2010 self-response rates by state, county, and census tract. On a statewide level, the discussion below highlights which states improved or fell below their 2000 self-response rates in 2010, providing a data-driven incentive to do even better in 2020.
Nationwide, the final mail response rate in 2010 was almost 1 percentage point less than in 2000, decreasing from 67.4% in 2000 to 66.5% in 2010.
2000 mail response rate from “Census 2000 Mail Response Rates: FINAL REPORT” (Census 2000 Evaluation A.7.a; January 30, 2003). 2010 mail response rate from “Mail Response/Return Rates Assessment: FINAL REPORT” (2010 Census Assessments; May 30, 2012).
Note also that in 2000, most households received a short form questionnaire and some households received a long form, a practice which ended in 2005 when the long form was replaced by the ongoing American Community Survey (which is sent to a much smaller share of households). Households that received the short form in 2000 – comparable in length to the 2010 Census form – had a mail response rate of 68.7%. Therefore, the decrease from the 2000 self-response rate for short form households only to all households in 2010 was a larger drop (just over two percentage points). The Census Bureau’s statewide data on 2000 self-responses is not limited to short form-only responses, however, so our analysis uses the overall statewide 2000 self-response rates.
Statewide mail response rates from the 2000 Census are available on the Census Bureau’s website at https://www.census.gov/dmd/www/response/2000response.html. Statewide mail response rates from the 2010 Census are available from https://www2.census.gov/dssd/.
But changes in mail response rates between 2000 and 2010 were uneven across the country. At the state level, 17 states plus the District of Columbia improved over the nationwide trend and increased their self-response rates between 2000 and 2010. South Carolina and Washington, DC led the increase, increasing their self-response rates by 6 percentage points or more:
- South Carolina increased by 6.7 points, from 58% in 2000 to 64.7% in 2010; and
- Washington, DC increased by 6 points, from 60% in 2000 to 66% in 2010.
Although the other 16 states improved by smaller amounts, several of these states exceeded the national 2010 self-response rate, such as Illinois (70.5%), Pennsylvania (70.2%), and Indiana (69.6%). One state – Florida – matched its 2000 rate in 2010 of 63%.
The remaining 32 states had lower self-response rates in 2010 compared to 2000, and most of these rates fell by a greater amount than the national decrease from 2000 to 2010 of almost one percentage point. For example, South Dakota's 2010 rate of 67.1% was almost 7 points less than its 2000 rate of 74%. West Virginia’s rate fell by almost 5 points, from 64% in 2000 to 59.1% in 2010. (See Table 1, below.)
TABLE 1. Statewide Census Mail Response Rates in 2000 and 2010, sorted by largest to smallest change from 2000 to 2010
| State | 2000 Mail Response Rate* | 2010 Mail Response Rate | Change (in percentage points) |
| South Carolina | 58% | 64.7% | 6.7 |
| District of Columbia | 60% | 66.0% | 6.0 |
| Hawaii | 60% | 64.1% | 4.1 |
| Tennessee | 65% | 67.1% | 2.1 |
| New York | 63% | 64.6% | 1.6 |
| Alabama | 61% | 62.5% | 1.5 |
| Illinois | 69% | 70.5% | 1.5 |
| Washington | 66% | 67.2% | 1.2 |
| Delaware | 63% | 64.1% | 1.1 |
| Louisiana | 60% | 61.0% | 1.0 |
| North Carolina | 64% | 64.8% | 0.8 |
| Indiana | 69% | 69.6% | 0.6 |
| Utah | 68% | 68.6% | 0.6 |
| Maryland | 69% | 69.5% | 0.5 |
| Texas | 64% | 64.4% | 0.4 |
| Vermont | 60% | 60.3% | 0.3 |
| Pennsylvania | 70% | 70.2% | 0.2 |
| Idaho | 67% | 67.1% | 0.1 |
| Florida | 63% | 63.0% | 0.0 |
| Massachusetts | 69% | 68.8% | -0.2 |
| Kentucky | 66% | 65.7% | -0.3 |
| Alaska | 56% | 55.6% | -0.4 |
| New Jersey | 68% | 67.6% | -0.4 |
| Connecticut | 70% | 69.5% | -0.5 |
| Minnesota | 75% | 74.1% | -0.9 |
| Kansas | 71% | 70.0% | -1.0 |
| Oregon | 68% | 66.9% | -1.1 |
| Rhode Island | 67% | 65.7% | -1.3 |
| Missouri | 69% | 67.5% | -1.5 |
| Wisconsin | 75% | 73.5% | -1.5 |
| Oklahoma | 64% | 62.3% | -1.7 |
| Arizona | 63% | 61.3% | -1.7 |
| Mississippi | 63% | 61.3% | -1.7 |
| Arkansas | 64% | 62.3% | -1.7 |
| California | 70% | 68.2% | -1.8 |
| New Mexico | 62% | 60.0% | -2.0 |
| Georgia | 65% | 62.5% | -2.5 |
| Wyoming | 66% | 63.4% | -2.6 |
| New Hampshire | 67% | 64.4% | -2.6 |
| Colorado | 70% | 67.2% | -2.8 |
| Iowa | 76% | 73.0% | -3.0 |
| Ohio | 72% | 69.0% | -3.0 |
| Virginia | 72% | 69.0% | -3.0 |
| North Dakota | 72% | 68.8% | -3.2 |
| Michigan | 71% | 67.7% | -3.3 |
| Montana | 68% | 64.6% | -3.4 |
| Maine | 61% | 57.4% | -3.6 |
| Nebraska | 75% | 71.1% | -3.9 |
| Nevada | 66% | 61.4% | -4.6 |
| West Virginia | 64% | 59.1% | -4.9 |
| South Dakota | 74% | 67.1% | -6.9 |
*NOTE: Statewide mail response rates from the 2000 Census are published by the Census Bureau only as integers with no decimal places.
Why Self-Response Rates Are Important
When households fill out the census questionnaire on their own, they help the Census Bureau save time and money and collect the highest quality population data.
Equally important, when a household self-responds, it avoids a visit from a census enumerator who will try to collect data from the household in person. The effort to count households that do not self-respond is expensive and challenging.
If an area has a low self-response rate, more of its households will need to be counted in-person, increasing the risk that people will be missed or counted inaccurately. In 2010, states with low self-response rates (even if they had improved over 2000) tended to have the greatest percentages of people missed (i.e., omissions) in the 2010 Census.
Census “omissions”
Despite the Census Bureau’s best efforts and those of local “trusted partner” organizations helping to “get out the count,” some people are missed during the census. The Bureau estimated that it missed about 16 million people nationwide in the 2010 Census. (see U.S. Census Bureau, “DSSD 2010 CENSUS COVERAGE MEASUREMENT MEMORANDUM SERIES #2010-G-01” May 22, 2012.)
On a nationwide basis, the number of people missed is offset by people who are included in the census by mistake (such as students away at college whose parents mistakenly include the students on their own census forms, or people with more than one home who fill out the census at both locations), and by counts of people added to the census using a statistical method called “imputation” – determining the count and population characteristics of similar households nearby and applying them to a household where people were living but could not be reached directly.
The Census Bureau estimated that in 2010, the number of people missed (omissions) was equivalent to the number of people counted twice, otherwise counted erroneously (such people who died before Census Day or were counted in the wrong place), or counted through imputation. This resulted in a “net overcount” in 2010 that was statistically equal to zero – in other words, an accurate nationwide count.
Nationwide net undercount/overcount masks concerns about local census quality
But Terri Ann Lowenthal, a former staff director of the Congressional census oversight subcommittee and consultant to FCCP’s Funders Census Initiative, cautioned that political representation and government resources are not allocated based on national numbers. “At the local level, the number of people missed might not be offset by the number counted twice or mistakenly, in part because the people more likely to be missed often do not live in the same communities as those who are more likely to be counted twice. This can result in an undercount locally or across population subgroups that results in unfair political representation and skewed distribution of resources.”
The problem of omissions in the decennial census has been documented by experts such as Dr. William O’Hare in several publications and the staff of the New York City Department of City Planning’s Population Division. (See Differential Undercounts in the U.S. Census: Who is Missed? as cited above, and Understanding Who Was Missed in the 2010 Census prepared for the Population Reference Bureau August 13, 2019.)
A recent report by Dr. O’Hare (see p. 17) concludes by noting that:
Obtaining an accurate count of state and local populations is important because the data affect the balance of political power across geographic areas and are widely used for state and local decision-making. A comprehensive picture of census accuracy requires assessment of the number, characteristics, and geographic locations of those who are missed in the census in addition to analysis of net undercount rates. By understanding who was omitted in the 2010 Census, community leaders, advocates, and others can better target geographic areas and population subgroups for Get-Out-the-Count efforts to reduce the number of people who are missed in the 2020 Census and improve the accuracy of the count for state and local populations.
A recent paper by NYC Department of City Planning staff discusses the problems with census omissions and describes census self-responses as “the gold standard in decennial census data collection and … the most accurate and efficient source of data.” Where self-response is low, these areas are at risk of greater omissions, which lead to undercounts and poorer census data quality.
Omissions are correlated with census self-response
Table 2 below shows the relationship by state between 2010 self-response rates and 2010 omission percentages calculated by the Census Bureau.
TABLE 2. Statewide 2010 Response Rates and Omissions Rates, sorted by largest to smallest omission rate
| State | 2010 Mail Response Rate | 2010 Omission Percentage |
| District of Columbia | 66.0% | 9.0% |
| Mississippi | 61.3% | 8.9% |
| Hawaii | 64.1% | 7.8% |
| Alabama | 62.5% | 7.7% |
| New Mexico | 60.0% | 7.7% |
| West Virginia | 59.1% | 7.7% |
| North Carolina | 64.8% | 7.6% |
| Florida | 63.0% | 7.5% |
| Arizona | 61.3% | 7.3% |
| Georgia | 62.5% | 7.3% |
| Nevada | 61.4% | 6.9% |
| Texas | 64.4% | 6.9% |
| Louisiana | 61.0% | 6.8% |
| Oklahoma | 62.3% | 6.4% |
| Wyoming | 63.4% | 6.4% |
| Delaware | 64.1% | 6.2% |
| Montana | 64.6% | 6.1% |
| New York | 64.6% | 6.1% |
| Maryland | 69.5% | 6.0% |
| Colorado | 67.2% | 5.9% |
| Idaho | 67.1% | 5.8% |
| Tennessee | 67.1% | 5.8% |
| Virginia | 69.0% | 5.8% |
| Massachusetts | 68.8% | 5.7% |
| Alaska | 55.6% | 5.5% |
| Kentucky | 65.7% | 5.5% |
| Arkansas | 62.3% | 5.4% |
| Vermont | 60.3% | 5.4% |
| South Carolina | 64.7% | 5.2% |
| California | 68.2% | 5.1% |
| New Hampshire | 64.4% | 5.0% |
| Rhode Island | 65.7% | 4.9% |
| South Dakota | 67.1% | 4.9% |
| Utah | 68.6% | 4.9% |
| Illinois | 70.5% | 4.6% |
| Michigan | 67.7% | 4.5% |
| Missouri | 67.5% | 4.5% |
| New Jersey | 67.6% | 4.5% |
| Pennsylvania | 70.2% | 4.5% |
| Washington | 67.2% | 4.5% |
| Minnesota | 74.1% | 4.4% |
| Maine | 57.4% | 4.2% |
| Wisconsin | 73.5% | 4.1% |
| Oregon | 66.9% | 4.0% |
| Connecticut | 69.5% | 3.9% |
| North Dakota | 68.8% | 3.9% |
| Kansas | 70.0% | 3.7% |
| Indiana | 69.6% | 3.6% |
| Ohio | 69.0% | 3.5% |
| Nebraska | 71.1% | 3.1% |
| Iowa | 73.0% | 2.6% |
See Table 14 for the omission percentages from the U.S. Census Bureau “DSSD 2010 CENSUS COVERAGE MEASUREMENT MEMORANDUM SERIES #2010-G-01” (May 22, 2012).
A statistical analysis of these two metrics shows they have a strong, inverse relationship; the Pearson value (a commonly-used correlation statistic) for the data in Table 2 is -.611. The negative value means the two measures are inversely correlated — that is, as self-response rates decrease, omission rates tend to increase, and vice versa. The range of correlation values is between -1 (the strongest negative relationship) and 1 (the strongest positive relationship). Therefore, the -.611 value is relatively strong.
Therefore, efforts by state and local officials and census stakeholders across the country to boost self-response rates by urging householders to fill out the census questionnaire on their own — either online, by phone, or by mail — will help protect localities against the risk of being undercounted.
