Data
Collection Procedures
Enumeration
and Residence Rules
Processing
Procedures
In accordance with census practice dating back to the first United
States census in 1790, each person was to be enumerated as an in-
habitant of his or her "usual residence" in the 1990 census. Usual
residence is the place where the person lives and sleeps most of the
time or considers to be his or her usual residence. This place is not
necessarily the same as the person's legal residence or voting residence.
In the vast majority of cases, however, the use of these different bases
of classification would produce substantially the same statistics,
although there might be appreciable differences for a few areas.
The implementation of this practice has resulted in the establishment
of rules for certain categories of persons whose usual place of residence
is not immediately apparent. Furthermore, this practice means that per-
sons were not always counted as residents of the place where they
happened to be staying on Census Day (April 1, 1990).
Enumeration Rules
Each person whose usual residence was in the United States was to be
included in the census, without regard to the person's legal status or
citizenship. In a departure from earlier censuses, foreign diplomatic
personnel participated voluntarily in the census, regardless of their
residence on or off the premises of an embassy. As in previous
censuses, persons in the United States specifically excluded from the
census were foreign travelers who had not established a residence.
Americans with a usual residence outside the United States were not
enumerated in the 1990 census. United States military and Federal
civilian employees, and their dependents overseas, are included in the
population counts for States for purposes of Congressional apportionment,
but are excluded from all other tabulations for States and their sub-
divisions. The counts of United States military and Federal civilian
employees, and their dependents, were obtained from administrative
records maintained by Federal departments and agencies. Other Americans
living overseas, such as employees of international agencies and private
businesses and students, were not enumerated, nor were their counts
obtained from administrative sources. On the other hand, Americans
temporarily overseas were to be enumerated at their usual residence in
the United States.
Residence Rules
Each person included in the census was to be counted at his or her
usual residence--the place where he or she lives and sleeps most of the
time or the place where the person considers to be his or her usual
home. If a person had no usual residence, the person was to be counted
where he or she was staying on April 1, 1990.
Persons temporarily away from their usual residence, whether in the
United States or overseas, on a vacation or on a business trip, were
counted at their usual residence. Persons who occupied more than one
residence during the year were counted at the one they considered to be
their usual residence. Persons who moved on or near Census Day were
counted at the place they considered to be their usual residence.
Persons in the Armed Forces--
Members of the Armed Forces were counted as residents of the area in
which the installation was located, either on the installation or in the
surrounding community. Family members of Armed Forces personnel were
counted where they were living on Census Day (for example, with the Armed
Forces person or at another location).
Each Navy ship not deployed to the 6th or 7th Fleet was attributed to
the municipality that the Department of the Navy designated as its
homeport. If the homeport included more than one municipality, ships
berthed there on Census Day were assigned by the Bureau of the Census
to the municipality in which the land immediately adjacent to the dock
or pier was actually located. Ships attributed to the homeport, but not
physically present and not deployed to the 6th or 7th Fleet, were
assigned to the municipality named on the Department of the Navy's
homeport list. These rules also apply to Coast Guard vessels.
Personnel assigned to each Navy and Coast Guard ship were given the
opportunity to report a residence off the ship. Those who did report an
off-ship residence in the communities surrounding the homeport were
counted there; those who did not were counted as residents of the ship.
Personnel on Navy ships deployed to the 6th or 7th Fleet on Census Day
were considered to be part of the overseas population.
Persons on Maritime Ships--
Persons aboard maritime ships who reported an off-ship residence were
counted at that residence. Those who did not were counted as residents
of the ship, and were attributed as follows:
1. The port where the ship was docked on Census Day, if that port was
in the United States or its territories.
2. The port of departure if the ship was at sea, provided the port
was in the United States or its territories.
3. The port of destination in the United States or its territories,
if the port of departure of a ship at sea was a foreign port.
4. The overseas population if the ship was docked at a foreign port
or at sea between foreign ports. (These persons were not included
in the overseas population for apportionment purposes.)
Persons Away at School--
College students were counted as residents of the area in which they
were living while attending college, as they have been since the 1950
census. Children in boarding schools below the college level were
counted at their parental home.
Persons in Institutions--
Persons under formally authorized, supervised care or custody, such as
in Federal or State prisons; local jails; Federal detention centers;
juvenile institutions; nursing, convalescent, and rest homes for the
aged and dependent; or homes, schools, hospitals, or wards for the
physically handicapped, mentally retarded, or mentally ill, were
counted at these places.
Persons Away From Their Usual Residence on Census Day--
Migrant agricultural workers who did not report a usual residence
elsewhere were counted as residents of the place where they were on
Census Day. Persons in worker camps who did not report a usual
residence elsewhere were counted as residents of the camp where they
were on Census Day.
In some parts of the country, natural disasters displaced significant
numbers of households from their usual place of residence. If these
persons reported a destroyed or damaged residence as their usual
residence, they were counted at that location.
Persons away from their usual residence were counted by means of
interviews with other members of their families, resident managers, or
neighbors.
The 1990 census was conducted primarily through self-enumeration.
The questionnaire packet included general information about the 1990
census and an instruction guide explaining how to complete the
questionnaire. Spanish-language questionnaires and instruction guides
were available on request. Instruction guides also were available in
32 other languages.
Enumeration of Housing Units
Each housing unit in the country received one of two versions of the
census questionnaire:
1. A short-form questionnaire that contained a limited number of
basic population and housing questions; these questions were
asked of all persons and housing units and are often referred
to as 100-percent questions.
2. A long-form questionnaire that contained the 100-percent items
and a number of additional questions; a sampling procedure was
used to determine those housing units that were to receive the
long-form questionnaire.
Three sampling rates were employed. For slightly more than one-half
of the country, one in every six housing units (about 17 percent)
received the long-form or sample questionnaire. In functioning local
governmental units (counties and incorporated places, and in some parts
of the country, towns and townships) estimated to have fewer than 2,500
inhabitants, every other housing unit (50 percent) received the sample
questionnaire in order to enhance the reliability of the sample data
for these small areas. For census tracts and block numbering areas
having more than 2,000 housing units in the Census Bureau's address
files, one in every eight housing units (about 13 percent) received a
sample questionnaire, providing reliable statistics for these areas
while permitting the Census Bureau to stay within a limit of 17.7
million sample questionnaires, or a one-in-six sample, nationwide.
The mail-out/mail-back procedure was used mainly in cities, suburban
areas, towns, and rural areas where mailing addresses consisted of a
house number and street name. In these areas, the Census Bureau
developed mailing lists that included about 88.4 million addresses.
The questionnaires were delivered through the mail and respondents were
to return them by mail. Census questionnaires were delivered 1 week
before Census Day (April 1, 1990)
The update/leave/mail-back method was used mainly in densely populated
rural areas where it was difficult to develop mailing lists because
mailing addresses did not use house number and street name. The Census
Bureau compiled lists of housing units in advance of the census.
Enumerators delivered the questionnaires, asked respondents to return
them by mail, and added housing units not on the mailing lists. This
method was used mainly in the South and Midwest, and also included some
high-rise, low-income urban areas. A variation of this method was used
in urban areas having large numbers of boarded-up buildings. About 11
million housing units were enumerated using this method.
The list/enumerate method (formerly called conventional or door-to-door
enumeration) was used mainly in very remote and sparsely-settled areas.
The United States Postal Service delivered unaddressed short-form
questionnaires before Census Day. Starting a week before Census Day,
enumerators canvassed these areas, checked that all housing units
received a questionnaire, created a list of all housing units,
completed long-form questionnaires, and picked up the completed
short-form questionnaires. This method was used mainly in the West and
Northeast to enumerate an estimated 6.5 million housing units.
Followup
Nonresponse Followup--
In areas where respondents were to mail back their questionnaires, an
enumerator visited each address from which a questionnaire was not
received.
Coverage and Edit-Failure Followup--
In the mail-back areas, some households returned a questionnaire that
did not meet specific quality standards because of incomplete or
inconsistent information, or the respondent had indicated difficulty in
deciding who was to be listed on the questionnaire. These households
were contacted by telephone or by personal visit to obtain the missing
information or to clarify who was to be enumerated in the household. In
areas where an enumerator picked up the questionnaires, the enumerator
checked the respondent-filled questionnaire for completeness and
consistency.
Special Enumeration Procedures
Special procedures and questionnaires were used for the enumeration
of persons in group quarters, such as college dormitories, nursing
homes, prisons, military barracks, and ships. The questionnaires
(Individual Census Reports, Military Census Reports, and Shipboard
Census Reports) included the 100-percent population questions but did
not include any housing questions. In all group quarters, all persons
were asked the basic population questions; in most group quarters,
additional questions were asked of a sample (one-in-six) of persons.
Shelter and Street Night (S-Night)
The Census Bureau collected data for various components of the
homeless population at different stages in the 1990 census. "Shelter
and Street Night" (S-Night) was a special census operation to count
the population in four types of locations where homeless people are
found. On the evening of March 20, 1990, and during the early morning
hours of March 21, 1990, enumerators counted persons in pre-identified
locations:
1. Emergency shelters for the homeless population (public and
private; permanent and temporary).
2. Shelters with temporary lodging for runaway youths.
3. Shelters for abused women and their children.
4. Open locations in streets or other places not intended for
habitation.
Emergency shelters include all hotels and motels costing $12 or less
(excluding taxes) per night regardless of whether persons living there
considered themselves to be homeless, hotels and motels (regardless of
cost) used entirely to shelter homeless persons, and pre-identified
rooms in hotels and motels used for homeless persons and families.
Enumeration in shelters usually occurred from 6 p.m. to midnight;
street enumeration, from 2 a.m. to 4 a.m.; abandoned and boarded-up
buildings from 4 a.m. to 8 a.m.; and shelters for abused women, from 6
p.m. on March 20 to noon on March 21.
Other components, which some consider as part of the homeless
population, were enumerated as part of regular census operations. These
include persons doubled up with other families, as well as persons with
no other usual home living in transient sites, such as commercial
campgrounds, maternity homes for unwed mothers, and drug/alcohol abuse
detoxification centers. In institutions, such as local jails and mental
hospitals, the Census Bureau does not know who has a usual home else-
where; therefore, even though some are literally homeless, these persons
cannot be identified separately as a component of the homeless population.
There is no generally agreed-upon definition of "the homeless,"
and there are limitations in the census count that prevent obtaining a
total count of the homeless population under any definition. As such,
the Census Bureau does not have a definition and will not provide a
total count of "the homeless." Rather, the Census Bureau will provide
counts and characteristics of persons found at the time of the census
in selected types of living arrangements. These selected components
can be used as building blocks to construct a count of homeless persons
appropriate to particular purposes as long as the data limitations are
taken into account.
In preparation for "Shelter-and-Street-Night" enumeration, the
regional census centers (RCC's) mailed a certified letter (Form D-33
(L)) to the highest elected official of each active functioning
government of the United States (more than 39,000) requesting them to
identify:
1. All shelters with sleeping facilities (permanent and temporary,
such as church basements, armories, public buildings, and so forth,
that could be open on March 20).
2. Hotels and motels used to house homeless persons and families.
3. A list of outdoor locations where homeless persons tend to be at
night.
4. Places such as bus or train stations, subway stations, airports,
hospital emergency rooms, and so forth, where homeless persons
seek shelter at night.
5. The specific addresses of abandoned or boarded-up buildings where
homeless persons were thought to stay at night.
The letter from the RCC's to the governmental units emphasized the
importance of listing night-time congregating sites. The list of
shelters was expanded using information from administrative records and
informed local sources. The street sites were limited to the list
provided by the jurisdictions. All governmental units were eligible for
"Shelter and Street Night." For cities with 50,000 or more persons, the
Census Bureau took additional steps to update the list of shelter and
street locations if the local jurisdiction did not respond to the certi-
fied letter. Smaller cities and rural areas participated if the local
jurisdiction provided the Census Bureau a list of shelters or open public
places to visit or if shelters were identified through our inventory
development, local knowledge update, or during the Special Place Prelist
operation.
The Census Bureau encouraged persons familiar with homeless persons and
the homeless themselves to apply as enumerators. This recruiting effort
was particularly successful in larger cities.
For shelters, both long- and short-form Individual Census Reports
(ICR's) were distributed. For street enumeration, only short-form
ICR's were used. Persons in shelters and at street locations were
asked the basic population questions. Additional questions about social
and economic characteristics were asked of a sample of persons in
shelters only.
Enumerators were instructed not to ask who was homeless; rather, they
were told to count all persons (including children) staying overnight at
the shelters, and everyone they saw on the street except the police,
other persons in uniform, and persons engaged in employment or obvious
money-making activities other than begging and panhandling.
At both shelter and street sites, persons found sleeping were not
awakened to answer questions. Rather, the enumerator answered the sex
and race questions by observation and estimated the person's age to the
best of his or her ability. In shelters, administrative records and
information from the shelter operator were used, when available, for
persons who were already asleep.
Less than 1 percent of shelters refused to participate in the census
count at first. By the end of the census period, most of those
eventually cooperated and the number of refusals had been reduced to a
few. For the final refusals, head counts and population characteristics
were obtained by enumerators standing outside such shelters and counting
people as they left in the morning.
The "street" count was restricted to persons who were visible
when the enumerator came to the open, public locations that had been
identified by local jurisdictions. Homeless persons who were well
hidden, moving about, or in locations other than those identified by
the local governments were likely missed. The number missed will never
be known and there is no basis to make an estimate of the number missed
from census data. The count of persons in open, public places was
affected by many factors, including the extra efforts made to encourage
people to go to shelters for "Shelter and Street Night," the weather
(which was unusually cold in many parts of the country), the presence
of the media, and distrust of the census. Expectations of the number of
homeless persons on the street cannot be based on the number seen
during the day because the night-time situation is normally very
different as more homeless persons are in shelters or very well hidden.
For both "Shelter-and-Street-Night" locations, the Census Bureau
assumed that the usual home of those enumerated was in the block where
they were found (shelter or street).
The "Shelter-and-Street-Night" operation replaced and expanded
the 1980 Mission Night (M-Night) and Casual Count operations. These two
operations were aimed at counting the population who reported having no
usual residence. M-Night was conducted a week after Census Day, in
April 1980. Enumerators visited hotels, motels, and similar places
costing $4 or less each night; missions, flophouses, local jails and
similar places at which the average length of stay was 30 days or less;
and nonshelter locations, such as bus depots, train stations, and all
night movie theaters. Questions were asked of everyone, regardless of
age. Enumerators conducted M-Night up to midnight on April 8, 1980, and
returned the next morning to collect any forms completed after
midnight.
The Casual Count operation was conducted in May 1980 at additional
nonshelter locations, such as street corners, pool halls, welfare and
employment offices. This operation lasted for approximately 2 weeks.
Casual Count was conducted during the day only in selected large
central cities. Only persons who appeared to be at least 15 years of
age were asked if they had been previously enumerated. Casual Count was
actually a coverage-improvement operation. It was not specifically an
operation to count homeless persons living in the streets. Persons were
excluded if they said they had a usual home outside the city because it
was not cost effective to check through individual questionnaires in
another city to try to find the person.
Respondents returned many census questionnaires by mail to 1 of over 344 census district offices or to one of six processing offices. In these offices, the questionnaires were "checked in" and edited for completeness and consistency of the responses. After this initial processing had been performed, all questionnaires were sent to the processing offices. In the processing offices, the household questionnaires were microfilmed and processed by the Film Optical Sensing Device for Input to Computers (FOSDIC). For most items on the questionnaire, the information supplied by the respondent was indicated by filling circles in predesignated positions. FOSDIC electronically "read" these filled circles from the microfilm copy of the questionnaire and transferred the information to computer tape. The computer tape did not include individual names, addresses, or handwritten responses. The data processing was performed in several stages. All questionnaires were microfilmed, "read" by FOSDIC, and transferred to computer disk. Selected written entries in the race question on both the short and long forms were keyed from the microfilm and coded using the data base developed from the 1980 census and subsequent content and operational tests. Keying of other written entries on the long forms occurred in the seven processing offices. The information (for example, income dollar amounts or homeowner shelter costs) on these keyed files was merged with the FOSDIC data or processed further through one of three automated coding programs. The codes for industry, occupation, place-of-birth, migration, place-of-work, ancestry, language, relationship, race, and Hispanic origin were merged with the FOSDIC data for editing, weighting, and tabulating operations at Census Bureau headquarters. All responses to the questions on Individual Census Reports (ICR's), Military Census Reports (MCR's), and Shipboard Census Reports (SCR's) were keyed, not processed by microfilm or FOSDIC.