Comparability — Austria [top]

In the 2011 Austrian sample, stateless are combined with "unknown."

Comparability — Benin [top]

Naturalized citizens are only identified in 2013.

Comparability — Canada [top]

The 1991, 2001, and 2011 samples identify naturalized citizens, but the 1971 and 1991 do not. The universe for 1981 does not include inmates, while others include all persons.

Comparability — Ecuador [top]

Persons with a citizenship card or civil registration are classified as Ecuadorean citizens.

Comparability — Egypt [top]

Comparability — Fiji [top]

Visitors and permit holders in Fiji are considered non-citizens. These groups are identified separately in the source variable.

Comparability — Germany [top]

In the Germany 1987 census, persons who have German/foreign dual nationalities are categorized as German citizens; in addition, persons whose citizenship is included in the "other" category and stateless persons are not separately identified, so both are considered "not citizens."

Comparability — Greece [top]

The 1971, 1981, 1991, 2001, and 2011 samples classify both Greek and dual citizenship persons as Greek citizens.

Comparability — Honduras [top]

Naturalized citizens are only identified in 1961.

Comparability — Hungary [top]

In 2001, stateless and foreign citizens are coded as separate categories. However, these two categories are grouped together in 2011 and are classified as "not a citizen."

The 2001 sample identifies persons with two or more citizenships, but it does not specify whether they have Hungarian citizenship or not. These persons are coded as "unknown" in CITIZEN.

Comparability — Indonesia [top]

The 1980-1995 censuses group "stateless" persons with Chinese citizens, whereas the 2010 census separates these categories; the treatment of this population in 1971 and 2000 is unclear but presumably they are grouped into the non-citizen population per 1980-1995.

Comparability — Ireland [top]

In the Ireland 2002 census, persons without nationality are included within the unknown category; in 2006 and 2011, persons without nationality are separately identified.

Comparability — Italy [top]

Comparability — Laos [top]

The source variables for all samples distinguish between citizens of Asian and non-Asian countries.

Comparability — Malaysia [top]

The universe for the question in 1970 and 1980 was age 12 and older, while it was asked of all persons in 1991 and 2001.

Comparability — Mali [top]

Persons with dual nationality were to report their most recent country of citizenship; those with uncertain status were to report country of birth.

Comparability — Palestine [top]

The 2007 census did not ask the question of persons in the area of Jerusalem annexed by Israel in 1967.

Comparability — Poland [top]

In 2002 and 2011, Polish persons and those with an additional citizenship (besides Polish) are classified as citizens. The 2011 identifies stateless persons.

Comparability — Romania [top]

The 1992 sample includes stateless persons. The 2011 sample identifies separately citizens by birth and by naturalization.

Comparability — Russia [top]

Data are comparable across samples. Both samples identify stateless persons.

Comparability — Rwanda [top]

The 1991 sample identifies naturalized citizens, but the 2002 sample does not make this distinction.

Comparability — Slovakia [top]

In 2001 and 2011, persons with multiple citizenship are classified as non-citizens. The original detail is retained in the unharmonized source variables.

Comparability — South Africa [top]

South African 1996 and 2011 census asked the citizenship question only of residents in private households. The 2001 and 2016 census asked the question of all persons.

Comparability — Spain [top]

Comparability — Switzerland [top]

In the Switzerland samples, persons who have Swiss/foreign dual nationalities are categorized as Swiss citizens.

In the 2011 sample, more detail is provided as to whether the respondent was a citizen by birth or naturalization.

Comparability — Turkey [top]

The 1990 and 2000 censuses identify persons without a nationality. Persons who have Turkish/foreign dual citizenship were classified as Turkish citizens.

Comparability — United States [top]

The pre-1940 U.S. samples only identify citizenship status for men age 21 and older. All others are coded to not in universe.

The 1900 and 1910 U.S. samples identify persons who were not yet citizens but had received "first papers." They are coded to non-citizens, but the information on first papers is preserved in the unharmonized source variables for those samples.

Comparability — Venezuela [top]

Venezuelan censuses did not ask the citizenship question to persons born in Venezuela, but IPUMS codes them as citizens. The 1981 sample has a much greater proportion of naturalized persons than the other samples.

Comparability — Zambia [top]

In 1990 and 2000, the question was asked of all persons. In 2010, the question was asked of present household members and visitors. The 1990 and 2000 enumeration instructions indicate that this question should have been asked only of present household members and visitors, but citizenship is reported for almost all absent household members; they are included in the universe.