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Glossary and Abbreviations

ACS: American Community Survey

Active Block Resolution: In the original plan for In-Office Address Canvassing for the 2020 Census, a program that permitted Census Bureau analysts to virtually canvass “active blocks” flagged by Interactive Review through available information resources, such as state and local government property databases and commercial street-view imagery. In-office analysts could document and correct housing unit coverage problems based on the available evidence, permitting those blocks to be reclassified as “passive” and kept out of the In-Field Address Canvassing workload. Active Block Resolution began at the Census Bureau’s National Processing Center in spring 2016 but was discontinued in early 2017 due to budgetary constraints.

Address Canvassing: A major census operation to improve the completeness of the Master Address File, conducted in the year before the 2000, 2010, and 2020 Censuses. The operation is particularly focused on addresses that will be included in the main census mailings, i.e., census blocks in the Mailout/Mailback (2000 and 2010) and Self Response (2020) type of enumeration area. The 2000 Census Block Canvassing operation and the 2010 Census Address Canvassing operation were both intended to send field staff to every address and street in every block in the designated areas, with the 2010 Address Canvassing operation being the only 2010 operation to utilize handheld computers for data collection (thus acquiring map-spot location for addresses whenever possible). The 2020 Census Address Canvassing operation had both an In-Office and an In-Field component,

with the In-Office program further divided into several subcomponents (most prominently, Interactive Review and Active Block Resolution) until some of the subcomponents were discontinued for budgetary reasons. In support of the 2020 Census, In-Field Address Canvassing operated between August–October 2019, with temporary-hire listers carrying out the field operation using laptop computers (and not the smartphones used in later 2020 Census field operations).

Administrative records: Records that are collected as part of the operation of federal, state, and local programs, typically fund allocation and tax programs. A prominent part of the research program of the 2010 and 2000 Censuses, administrative records were given wider use in the 2020 Census, both for the identification of probable vacant housing units and for the enumeration of occupied housing units (in lieu of multiple field visits in some cases and as a last resort in others).

American Community Survey (ACS): The U.S. Census Bureau’s continuous survey program to measure detailed socioeconomic and other data that now operates in parallel with the decennial census. In the 2010 Census, the ACS formally replaced the long-form sample of households that had been administered a more detailed questionnaire in previous decades, making the 2010 and 2020 Censuses short-form-only.

Apportionment: The reallocation of the 435 seats in the U.S. House of Representatives, on the basis of population size, using data from a new decennial census. Under current law, apportionment is conducted using the method of equal proportions.

Area Census Office: In the 2020 Census, a temporary office established to support decennial census field operations, in turn overseen by one of the temporary Regional Census Centers; in the 2010 Census, these offices were known as Local Census Offices. The 2020 Census used a field infrastructure consisting of 248 Area Census Offices divided between 6 Regional Census Centers, generally colocated in the cities containing Census Bureau Regional Offices (Atlanta, Chicago, Los Angeles, New York, and Philadelphia, with the Denver region’s Regional Census Center being established in Dallas). By comparison, the 2010 Census used 494 Local Census Offices across 12 Regional Census Centers (the Census Bureau consolidated to six operational regions in 2012).

ASA: American Statistical Association

CEF: Census Edited File

Census Edited File (CEF): The third major step in the product flow for post data collection processing in the 2020 Census, following the Census Unedited File. The Census Edited File includes additional edits and imputation (affecting the characteristics of persons or housing units but not the overall counts), and is effectively the complete data set for all items in the census. The Census Edited File is processed by the Disclosure Avoidance

System to protect confidentiality of census responses; in the 2020 Census, it is the resulting Microdata Detail File is used for tabulation of census products, rather than the Census Edited File.

Census Review Analysis and Visualization Application (CRAVA): Data visualization and analytical software developed by the Census Bureau to permit its staff and subject matter experts to review and correct problems during the post data collection processing stage of the Census (i.e., progressing from Decennial Response File to Census Unedited File to Census Edited File). It is no longer in use.

CUF: Census Unedited File

Census Unedited File (CUF): The second major step in the product flow for post data collection processing in the 2020 Census, following the Decennial Response File 2. The Census Unedited File reflects the application of household count imputation and so represents the final universe of address and population counts; accordingly, the state-level apportionment counts are generated from the Census Unedited File.

Coverage Measurement: A primary means of measuring census quality by estimating undercount and overcount for the nation as a whole and for specific demographic groups. The set of census enumerations from a sample of clusters of census blocks (known as the “E-sample”) is matched to the results of an independent postenumeration survey (PES) conducted in the same sample of block clusters, and the statistical technique of dual-systems estimation is used to estimate under- or overcount. In the 2020 Census, “Coverage Measurement” is the heading used to describe component operations related to this work, though the underlying survey (and hence the program as a whole) is commonly termed the Postenumeration Survey or “PES.” In the 2010 Census, the corresponding suite of operations was known as “Census Coverage Measurement” (CCM); in the 2000 Census, it was the “Accuracy and Coverage Evaluation” (A.C.E.).

CRAVA: Census Review Analysis and Visualization Application

DA: Demographic analysis

DAS: Disclosure Avoidance System

Decennial Response File (DRF): The first major step in the product flow for post data collection processing in the 2020 Census, in two stages. The Decennial Response File 1 is the general compilation of all responses by all modes, including duplicate responses; Decennial Response File 2 reflects unduplication of census returns across households using the Census Bureau’s proprietary Primary Selection Algorithm.

Delivery Sequence File (DSF): The master database of deliverable mail addresses maintained by the U.S. Postal Service, organized by carrier route. First used as a source of address updates to the Census Bureau’s Master Address File for the 2000 Census, regular “refreshes” from the DSF

remained a primary source of new address information in the 2010 and 2020 Censuses.

Demographic analysis (DA): A census coverage measurement technique that derives population estimates of national and major demographic subgroups (that are independent of the current census) based on administrative records data on births, deaths, immigration, and emigration. Demographic analysis estimates have been extended back to the 1940 Census.

Differential privacy: A system for sharing information that imposes quantifiable limits on the disclosure of information about individual records in the database, as through the injection of statistical noise into all data cell entries. In the 2020 Census, the Census Bureau decided to implement a new Disclosure Avoidance System (DAS) premised on differential privacy methods; the TopDown Algorithm is the specific differentially private (or formally private) algorithm used to generate the first major 2020 Census data products after the state-level apportionment populations: namely, the redistricting data required under P.L. 94-171 and the forthcoming Demographic and Housing Characteristics files. See also privacy-loss budget.

Disclosure Avoidance System (DAS): The intermediary system between the Census Edited File and the final data files used for tabulation of census products that applies techniques to curb the risk of identification of census respondents. For the 2020 Census redistricting data, the 2020 Census Disclosure Avoidance System uses the TopDown Algorithm to take differentially private “noisy measurements”—crosstabulation cells with a controlled amount of statistical noise added to them—and convert them into a synthetic Microdata Detail File that is used for tabulation purposes.

DMAF: Decennial Master Address File; see Master Address File

DRF: Decennial Response File

DSF: Delivery Sequence File

GQ: Group quarters

Group quarters (GQ): A place where people live that is not a housing unit. Group quarters are commonly categorized as institutional (for example, correctional facilities and nursing or other health care facilities) or noninstitutional (for example, college student housing, military barracks, ships, group homes, worker dormitories, and shelters).

iCADE: The Integrated Computer Assisted Data Entry system to scan paper questionnaires and capture the data in electronic format for further processing. The iCADE system was developed within the Census Bureau and has been used in various Census Bureau surveys and some international censuses. Paper data capture was outsourced in the paper-based 2010 Census, but the in-house iCADE system was adopted to process paper questionnaires in the 2020 Census.

Interactive Review: Lead portion of the 2020 Census In-Office Address Canvassing program, beginning in fall 2015 and continuing through early

2019, in which analysts viewed Master Address File housing unit locations and counts superimposed on aerial imagery to identify change or stability in residential structures. Interactive Review was meant as a comprehensive but quick triage, classifying blocks as active (evidence that the number of housing units visible in imagery differs from number on Master Address File), passive (stable blocks, in terms of housing unit numbers in both sources), and on hold (blocks for which the available imagery was inconclusive). In the original program, the active blocks were sent to the Active Block Resolution stage; after that stage was discontinued, blocks unresolved in Interactive Review were sent to In-Field Address Canvassing (though a number of “trigger” events, such as the availability of updated imagery, could prompt another round of Interactive Review for blocks).

IT: Information technology

JASON: An independent group of scientists engaged to advise the federal government on science and technology matters, principally in the defense and intelligence arenas. JASON administratively operates through the MITRE Corporation; despite the capitalization, JASON is not an acronym.

MAF: Master Address File

Master Address File (MAF): The master list of addresses of residential and nonresidential addresses maintained by the Census Bureau. An extract of the residential addresses known as the Decennial Master Address File (DMAF) becomes the effective universe for the census enumeration. Since the 2000 Census, the Master Address File has been maintained as an ongoing resource for the Census Bureau’s censuses and surveys, updated using a variety of sources including the U.S. Postal Service Delivery Sequence File and, in the decade preceding the 2020 Census, a major Geographic Support System initiative to obtain address and geographic files from state, local, and tribal governments. Master Address File entries are linked to a specific geographic location (for eventual tabulation purposes) using the Census Bureau’s principal cartographic resource, the Topologically Integrated Geographic Encoding and Referencing (TIGER) System.

NASEM: National Academies of Sciences, Engineering, and Medicine

National Processing Center (NPC): The Census Bureau’s principal facility for collecting and processing the returns from its censuses and surveys, as well as to provide logistical and clerical support for decennial census field operations. The National Processing Center is located in Jeffersonville, Indiana. In the 2010 Census, the National Processing Center housed a data capture center that shared paper data capture responsibilities with two other centers (in Essex, Maryland, and Phoenix, Arizona) that were administered by external contractors; in the 2020 Census, paper data capture was shared between National Processing Center and a facility in Phoenix.

Non-ID Processing: The system in the 2020 Census to facilitate the collection of respondent information (including self-supplied usual residence information) without requiring the respondent to enter a Master Address File-keyed identifier code from a physical mailing to a household. In the 2010 Census, Non-ID nonreturns were primarily the blank-address “Be Counted” forms made available in public places for people to complete if they believed they had been missed in the census. However, in the 2020 Census, Non-ID Processing was critical to the extensive promotion of the notion of replying to the census anytime or anywhere, using the Internet response option. The address information collected in Non-ID Processing is compared and reconciled with the Master Address File, with ungeocoded addresses being designated for verification by field staff.

Nonresponse Follow-up (NRFU): The census field operation whereby census enumerators attempt to collect responses from households for which no response was obtained by self-response methods (in the 2020 Census, by Internet, mail, or phone) or returning a questionnaire left with the housing unit in Update Leave. In the 2010 Census, Nonresponse Follow-up was performed exclusively on paper questionnaires, with assignments parceled out to individual enumerators through a hierarchy of field staff. The 2020 Census utilized electronic interviewing on smartphones, with assignments being pushed out to enumerators’ devices on a nightly basis; particularly in the early stages, the enumerator was also given an optimized route to follow in conducting the interview attempts. Nonresponse Follow-up in the 2020 Census was also the first in which the availability of reliable administrative records data for a household could be used for enumeration in lieu of second and subsequent enumerator visits.

NPC: National Processing Center

NRFU: Nonresponse Follow-up

PES: Postenumeration survey

Postenumeration survey (PES): Both a generic term for the independent, follow-up survey conducted in census coverage measurement programs based on dual-systems estimation and the specific operational name given to said survey in some decennial censuses (as done in 2020).

Privacy-loss budget: The parameter in a differential privacy implementation, technically defined as the maximum distance between queries performed on two databases that differ from each other by one entry, that is conceptualized as the amount of information disclosure risk that will be tolerated. The privacy-loss budget is commonly denoted by and characterized as a slider between privacy and accuracy, → 0 meaning perfect privacy and zero accuracy and → ∞ connoting absolute accuracy and zero privacy. The Disclosure Avoidance System allocates certain shares of overall to specific histogram cells and different levels of geographic

tabulation, thus determining the amount of statistical noise added to the cells.

Service-Based Enumeration (SBE): In the 2010 and 2020 Censuses, the component of the broader Group Quarters Enumeration program focused on people experiencing homelessness who could be reached at service or shelter locations or in certain targeted non-sheltered outdoor locations. In 2010, the program was spread across three days around the April 1 reference date, each day specific to a type of location; in the 2020 Census, Service-Based Enumeration had to be postponed until September 22–24.

Targeted nonsheltered outdoor locations (TNSOL): Technically designated as noninstitutional group quarters locations, areas where people experiencing homelessness are known to live without paying to stay, and where they are counted in the Service-Based Enumeration program.

TEA: Type of enumeration area

Type of enumeration area (TEA): A classification developed by the Census Bureau prior to a decennial census to determine the basic strategy that will be used to conduct the census in particular blocks (or, in 2020 Census terminology, basic collection units). The 2000 and 2010 Censuses each designated nine TEAs, while the 2020 Census utilized six TEAs: Self Response (subsuming the “Mailout/Mailback” TEA of the previous censuses), Update Enumerate, Update Leave, Island Areas (separate designation for the U.S. territories), Remote Alaska, and Military.

Update Enumerate: A method of census enumeration and type of enumeration area in which a census enumerator’s sole visit involves both Address Canvassing functions (adding or updating address list entries) and enumeration (conducting an interview with household respondents). Update Enumerate areas tend to be remote, rural geographic areas; Remote Alaska areas are counted using Update Enumerate methods but are designated as a separate type of enumeration area because they are approached earlier in the census year (beginning in January) due to physical accessibility concerns.

Update Leave: A method of census enumeration and type of enumeration area, primarily focused on geographic areas where the U.S. Postal Service does not do home delivery or in which there are other possible issues with mail delivery, in which a census enumerator conducts address list update activities in the area and leaves a questionnaire package at each housing unit. Update Leave was not originally planned to be a type of enumeration area in the 2020 Census, as it was in 2010, but it was reinstated in the 2020 Census plan in 2017. In addition to areas lacking mail delivery, Update Leave has also been applied to areas that have been affected by major disasters prior to the census.

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