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Frequently Asked Questions
Frequently Asked Questions
Do you have questions about responding to a Special Census?
Start by reading the Frequently Asked Questions (FAQs) in the PDF files below. These FAQs address questions we commonly hear from respondents. If you don't find the answer there, continue scrolling to the "Additional FAQs" section further down this page.
Additional FAQs
The U. S. Census Bureau provides the 2020 Census of Population and Housing results at:
The Census Bureau produces annual population estimates that may be retrieved at:
The Census Bureau also produces population estimates in the American Community Survey (ACS). These estimates may be retrieved at:
In addition, beginning in 2024 official census statistics will be posted on the website for governmental units that have conducted a special census.
A special census is a basic enumeration of population, housing units, and group quarters conducted by the Census Bureau at the request of a governmental unit.* They are conducted on a cost-reimbursable basis (see "Who Pays for a Special Census" section below). The Census Bureau's authority to conduct special censuses is specified in Title 13, United States Code, Section 196.
*For Special Census purposes, a governmental unit is defined as the government of any state, county, city, or other political subdivision within a state, or the government of the District of Columbia or the government of any possession or area including political subdivisions, American Indian Reservations, or Alaskan Native villages.
When local officials believe there has been a significant population change in their community due to growth, annexation, boundary changes, or the addition of new group quarters facilities such as a nursing home or a college, a special census may be beneficial.
Many states use special census population statistics to determine the distribution of state funds to local jurisdictions. Local jurisdictions may use the data to plan new schools, transportation systems, housing programs, or water treatment facilities. The updated information provided by a special census is designated as Official Census Statistics and may be used in any manner provided for by applicable law.
The data collected will not be used to update the official 2020 Census data products and apportionment counts, but they may be used to update data in the Census Bureau’s Population Estimates Program.
A partial special census is conducted using the same methodologies and procedures as a regular or full special census, but it is for a subset of areas within the jurisdiction of the local governmental unit.
The areas requested in a partial special census must contain at least one full Census Tract that is completely within the jurisdiction of the governmental unit and can contain additional contiguous tracts or blocks. For example, governmental units may choose to conduct a partial special census with just those tracts that might have experienced a large population growth or boundary change.
With a partial special census, the area being counted is typically much smaller, resulting in lower cost to the governmental unit. The information needed to process a cost estimate for conducting a partial special census is the same as that required for the standard special census.
During a partial special census, field representatives will canvass their assigned areas to update the address lists and census maps by adding housing units not already listed, make corrections to address information, and delete listings that do not exist. They will also attempt to enumerate each living quarter that has not self-responded.
The Census Bureau has been authorized to conduct special censuses since 1903. The nation’s first special census was conducted on April 15, 1915. Although the way the special censuses are conducted has changed, the basic objective to obtain updated population and housing counts remains the same.
For the 2020 Special Census Program, the Census Bureau will use an internet self-response instrument for respondents to self-respond to the Special Census Questionnaire. Respondents will have a predetermined number of weeks to respond to the Special Census Questionnaire using the internet self-response instrument.
At the start of the special census, the Census Bureau will send an invitation letter to known housing units in the governmental unit’s special census area with information needed to respond online. Reminder letters and postcards will be sent to each known housing unit to encourage self-response and provide information needed to do so.
After the end of the special census self-response period, the Census Bureau will conduct follow-up operations in the field to enumerate housing units that did not respond using the internet self-response instrument as well as housing units that did not receive mailed materials.
These housing units will be contacted by a field representative who will conduct a special census interview using a paper questionnaire. The field operations will also enumerate group quarters and transitory locations in the governmental unit’s special census area using a paper questionnaires.
During the field operations, special census field representatives will conduct listing to verify the current address lists for the special census area and add, delete, or update the addresses of living quarters as needed, based on their observation of housing units, transitory locations, and group quarters.
The Special Census Questionnaires will collect the same information that was gathered during the 2020 Census.
Please note that Domestic Violence Shelters are out of scope for the special census and will not be included in any special census enumeration.
Each person in a special census coverage area is identified as either a resident or nonresident of the housing unit as of the reference date for the special census. Since the first census in 1790, the Census Bureau has used the concept of usual residence when determining where people were to be counted. This concept has been followed in all subsequent censuses and is also used when conducting a special census. Usual residence is defined as the place where a person lives and sleeps most of the time. This place is not necessarily the same as the person's legal residence, voting residence, or where they prefer to be counted. Also, noncitizens who are living in the United States are included, regardless of their immigration status.
Determining usual residence is straightforward for most people. However, given our nation's wide diversity in types of living arrangements, the concept of usual residence has a variety of applications. Some examples of these living arrangements include people experiencing homelessness, people with a seasonal/second residence, people in group quarters, people in the process of moving, people in hospitals, children in shared custody arrangements, college students, live-in employees, military personnel, and people who live in workers’ dormitories.
Applying the usual residence concept to real living situations means that people will not always be counted at the place where they happen to be staying on the reference date for the special census or at the time they complete their questionnaire. So, the Census Bureau has documented the residence criteria that are used to determine where people are counted, along with descriptions of how the residence criteria apply to many specific residence situations. For example, people temporarily away from their usual residence on the special census reference date, such as on vacation or on a business trip, are counted at their usual residence. The residence criteria can be found at:
People who live or stay in more than one place during the week, month, or year are counted only if they live in the area, in which the cSpecial census is being conducted, most of the time. People who do not have a usual residence, or who cannot determine a usual residence, are counted where they are staying on the special census reference date.
Living Quarters
A living quarter is any place where someone lives or, in some cases, where people could potentially live. All living quarters are classified as either housing units or group quarters.
Housing Unit
A housing unit is a living quarter in which the occupant(s) live separately from any other person in the building and have direct access to their living quarters from the outside of the building or through a common hall. If the only way an occupant can get to their living area is through someone else's living area, they do not have direct access. Housing units are usually houses, apartments, mobile homes, groups of rooms, or single rooms that are occupied as separate living quarters. They are residences for single individuals, for groups of individuals, or for families who live together. For vacant housing units, the criteria of separateness and direct access are applied to the intended or previous occupants whenever possible.
Nontraditional living quarters, such as boats, recreational vehicles (RVs), tents, and caves, are classified as housing units if they are occupied by someone who has no usual residence elsewhere. However, these nontraditional structures are not considered to be living quarters if they are not occupied by at least one person who has no usual residence elsewhere.
Most nontraditional living quarters can be found at transitory locations, which are places where people are unlikely to live year-round due to the transitory/temporary/impermanent nature of the location. Transitory locations include places such as campgrounds, recreational vehicle (RV) parks, marinas, hotels, motels, racetracks, circuses, or carnivals. Generally, people living or staying at a transitory location either pay fees to stay there, or they work there temporarily. Each transitory location typically contains multiple separate units, which can be separate rooms in a lodging facility or separate spaces (such as sites, slips, or pads) where a tent, boat, RV or other structure may be parked or located.
Group Quarters
A group quarters is a place where people live or stay, in a group living arrangement that is owned or managed by an entity or organization providing housing and/or services for the residents. These services may include custodial or medical care as well as other types of assistance, and residency is commonly restricted to those receiving these services. This is not a typical household-type living arrangement. People living in group quarters are usually not related to each other. Group quarters include such places as college residence halls, residential treatment centers, skilled-nursing facilities, group homes, military barracks, correctional facilities, and workers’ dormitories.
Housing units and group quarters may coexist under the same entity or organization, and in some situations actually share the same structure. For example, an assisted living facility complex may have a skilled-nursing floor or wing that meets the definition of a nursing facility and is, therefore, a group quarters, while the rest of the living quarters in the facility are housing units. Group care facilities and continuing care retirement communities often consist of several different types of living quarters, with varying services and levels of care. Some of the living quarters in these facilities and communities are considered housing units, and some are considered group quarters, depending on which definition they meet.
The Census Bureau conducts special censuses on a cost-reimbursable basis, meaning the governmental unit requesting a special census will assume full responsibility for the cost of the count and will reimburse the Census Bureau for all costs incurred by the Census Bureau.
Before a governmental unit signs a memorandum of agreement and prior to the commencement of any work, the Census Bureau will calculate a cost estimate so the cost and scope of a special census can be formalized. A special census cost estimate will include, but is not limited to, field work, printing of the response material, data processing, and the delivery of special census results. The exact cost will vary based on several factors, such as duration of field activities, self-response rate, boundary changes due to annexations, and enumerator pay rate. Additional expenses a governmental unit may incur, such as community outreach, are not included in the cost estimate.
If your jurisdiction is interested in a special census, complete form SC-900, Special Census Cost Estimate Request, in full and submit it electronically to DCMD.Special.Census@census.gov.
Please note that a cost estimate will not be calculated until BOTH an official letter from your Highest Elected Official and the completed SC-900 are received by the Census Bureau. Once the required items are received, the Special Census Program will notify you of receipt. It may take several weeks for the Census Bureau to produce a cost estimate based on the information you provide in the SC-900.
The Special Census Program began accepting requests for cost estimates from governmental units starting on March 30, 2023, and will continue to accept requests through May 2027. Data collection will start no sooner than January 2024 and will conclude in September 2028, ahead of the 2030 Census.
The Census Bureau conducts special censuses on a cost-reimbursable basis. This means that the governmental unit requesting a special census assumes full responsibility for the cost of the special census.
A special census may be conducted for the government of any state, county, city, or other political subdivision within a state, for the government of the District of Columbia, or for the government of any possession or area, including political subdivisions, American Indian Reservations, and Alaskan Native villages, on subjects covered by the censuses provided for in Title 13, United States Code.
The governmental unit is responsible for reviewing their state's legislation to determine the circumstances under which a special census is applicable. For example, in Iowa, a city may have only one federal special census per decade. On the other hand, Illinois has no such restriction, and towns may conduct as many special censuses as they deem necessary.
The Special Census Program uses the same methodologies as the 2020 Census.
To improve the program from previous decades, the Census Bureau has:
- Implemented new collection methodologies including Internet Self-Response.
- Improved the quality of the data by using the Census Bureau's Master Address File (MAF).
- Expanded quality assurance procedures to include a Reinterview operation to improve efficiency and data quality.
- implemented an operations control system used to control and track data collection assignments.
- Modernized confidentiality protections through the implementation of the 2020 Census disclosure avoidance methodology. As a result, the minimum statistical area for which any partial special censuses can be conducted is a 2020 Census tabulation tract.
- Redesigned the hiring and payroll process. For the 2020 Special Census Program, the Census Bureau will recruit candidates with the assistance of the governmental unit and hire these candidates for the Special Census.
Please note the following change for partial census requests submitted for the 2020 Special Census program:
- The areas requested in a partial special census must contain at least one full Census Tract that is completely within the jurisdiction of the governmental unit and can contain additional contiguous tracts or blocks.
The 2020 Special Census Program will accept requests for cost estimates from governmental units starting in March 2023 and continuing through May 2027. Data collection will start no earlier than January 2024 and will continue through September 2028.
The Special Census Questionnaires are very similar to the 2020 Census questionnaires used in the associated operations (e.g., Internet Self-Response, Update/Enumerate, and Group Quarters Enumeration).
Some states distribute funds based on current population statistics. By conducting a special census, a community may be able to document a population or housing change from earlier censuses, which could lead to increased state revenue sharing or other benefits.
The updated information provided by a special census is designated as Official Census Statistics and may be used in any manner provided for by applicable law.
The governmental unit will conduct the recruiting with the help of the Census Bureau, which will provide support in publicizing and recruiting for the Special Census. The Census Bureau will hire these candidates for a special census, in a similar way that the Census Bureau hires field representatives for surveys. Training of selected candidates will be the responsibility of the Special Census Program staff. Paychecks will be issued by the Census Bureau and pay rates will be set based on the local area pay rates.
The full suite of data products for the Special Census Program includes:
- A letter from the Census Bureau director that contains the total population and total housing unit counts for the Special Census area,
- A special census data product with counts of the special census’ total population and total housing units by block
- 2020 Census tabulation tract-level (and above) demographic profiles. Demographic profiles will contain the same content as the 2020 Census demographic profiles.
Please note that some governmental units will not receive the full suite of data products.The geography included in the special census will impact which data products the governmental unit receives based on disclosure avoidance considerations.
The Census Bureau incorporates the results of full special censuses into the Population Estimates Program. Additionally, each annual time series produced will use the special census housing unit and household population values to estimate that particular July 1 date, so the estimates will build off of them for the rest of the decade. However, when the special census is for a subcounty place, such as a city, the updated results do not roll up to a new county or state total as those estimates are produced separately.
No, results of special censuses are not incorporated into counts for urban areas. Special Census areas and urban areas have different boundaries that prevent the special census data from being used to update urban areas.
The public is protected by Title 13 U.S. Code. Only authorized Census Bureau employees may see personally identifiable information. Results that could be used to identify an individual are not released. Census employees, including those hired on a temporary basis, swear under oath that they will not disclose any information gathered about individuals or businesses. Information collected by the Census Bureau is used only for statistical purposes--no one can obtain personally identifiable data from the Census Bureau.
Census confidentiality protections—what we call “disclosure avoidance”—have evolved over time to keep pace with emerging threats. Since the 1990 Census we have added “noise”—or variations from the actual count—to the collected data. For 2020 Census data we are applying noise using a newer protection framework based on “differential privacy.”
Learn more here about why and how we are modernizing our protections and how you can engage in the process: Understanding Differential Privacy
You may e-mail us at dcmd.special.census@census.gov.
Page Last Revised - December 1, 2023
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