Sampling Error Estimation

Table 2 summarizes IPUMS sample design characteristics, distinguishing between systematic and complex stratified samples (columns 1 and 2), samples of household and geographic clusters (columns 3 and 4), samples of individual person records (column 5), and samples that require differential weighting (column 6). For a description of sample design and standard error estimation, see the IPUMS Variance Estimation page. For more detailed information on sampling design, researchers should consult the documentation on the IPUMS Sample Descriptions page. Select column headings for more information and estimation recommendations.

Table 2: Sample Design Characteristics
Sample	Sample fraction (%)	Systematic sampling	Complex stratification	Geographic clustering	Household clustering	Persons not organized into households	Differential weighting
		1	2	3	4	5	6
Argentina 1970	2	X	.	.	X	.	.
Argentina 1980	10	X	.	.	X	.	X
Argentina 1991	10	X	.	.	X	.	X
Argentina 2001	10	X	.	.	X	.	.
Argentina 2010	10	X	.	.	X	.	.
Armenia 2001	10	X	.	.	X	.	.
Armenia 2011	10	X	.	.	X	.	.
Austria 1971	10	X	.	.	X	.	.
Austria 1981	10	X	.	.	X	.	.
Austria 1991	10	X	.	.	X	.	.
Austria 2001	10	X	.	.	X	.	.
Austria 2011	10	X	.	.	X	.	.
Bangladesh 1991	10	X	.	.	X	.	.
Bangladesh 2001	10	X	.	.	X	.	.
Bangladesh 2011	5	X	.	.	X	.	.
Belarus 1999	10	X	.	.	X	.	.
Belarus 2009	10	X	.	.	X	.	.
Benin 1979	10	X	.	.	X	.	.
Benin 1992	10	X	.	.	X	.	.
Benin 2002	10	X	.	.	X	.	.
Benin 2013	10	.	.	.	X	.	.
Bolivia 1976	10	X	.	.	X	.	.
Bolivia 1992	10	X	.	.	X	.	.
Bolivia 2001	10	X	.	.	X	.	.
Botswana 1981	10	X	.	.	X	.	.
Botswana 1991	10	X	.	.	X	.	.
Botswana 2001	10	X	.	.	X	.	.
Botswana 2011	10	X	.	.	X	.	.
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Sample	Sample fraction (%)	Systematic sampling	Complex stratification	Geographic clustering	Household clustering	Persons not organized into households	Differential weighting
		1	2	3	4	5	6
Brazil 1960	20	X	.	.	X	.	.
Brazil 1970	25	X	.	.	X	.	X
Brazil 1980	25	X	.	.	X	.	X
Brazil 1991	10	.	X	.	X	.	X
Brazil 2000	10	.	X	.	X	.	X
Brazil 2010	10	.	X	.	X	.	X
Burkina Faso 1985	10	X	.	.	X	.	.
Burkina Faso 1996	10	X	.	.	X	.	.
Burkina Faso 2006	10	X	.	.	X	.	.
Cambodia 1998	10	.	X	.	X	.	.
Cambodia 2004	1	.	X	X	X	.	X
Cambodia 2008	10	X	.	.	X	.	.
Cambodia 2013	1	.	X	X	X	.	X
Cameroon 1976	10	X	.	.	X	.	.
Cameroon 1987	10	X	.	.	X	.	.
Cameroon 2005	10	X	.	.	X	.	.
Canada 1971	1	.	.	.	.	X	.
Canada 1981	2	.	.	.	.	X	.
Canada 1991	3	.	.	.	.	X	.
Canada 2001	2.5	.	.	.	.	X	X
Canada 2011	2.7	.	X	.	X	.	X
Chile 1960	1	.	.	.	.	X	.
Chile 1970	10	X	.	.	X	.	.
Chile 1982	10	X	.	.	X	.	.
Chile 1992	10	X	.	.	X	.	.
Chile 2002	10	X	.	.	X	.	.
China 1982	1	X	.	.	X	.	.
China 1990	1	.	.	X	X	.	.
China 2000	1	X	.	.	X	.	.
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Sample	Sample fraction (%)	Systematic sampling	Complex stratification	Geographic clustering	Household clustering	Persons not organized into households	Differential weighting
		1	2	3	4	5	6
Colombia 1964	2	X	.	.	X	X	.
Colombia 1973	10	X	.	.	X	.	.
Colombia 1985	10	X	.	.	X	.	X
Colombia 1993	10	X	.	.	X	.	.
Colombia 2005	10	.	X	.	X	.	X
Costa Rica 1963	6	.	.	.	.	X	.
Costa Rica 1973	10	X	.	.	X	.	.
Costa Rica 1984	10	X	.	.	X	.	.
Costa Rica 2000	10	X	.	.	X	.	.
Costa Rica 2011	10	X	.	.	X	.	.
Cuba 2002	10	X	.	.	X	.	.
Dominican Republic 1960	6.6	.	.	.	.	X	.
Dominican Republic 1970	6.8	.	X	.	.	X	X
Dominican Republic 1982	8.5	.	X	.	X	.	X
Dominican Republic 2002	10	X	.	.	X	.	.
Dominican Republic 2010	10	X	.	.	X	.	.
Ecuador 1962	3	.	.	.	.	X	.
Ecuador 1974	10	.	X	.	X	.	X
Ecuador 1982	10	X	.	.	X	.	.
Ecuador 1990	10	X	.	.	X	.	.
Ecuador 2001	10	X	.	.	X	.	.
Ecuador 2010	10	X	.	.	X	.	.
Egypt 1986	13.5	.	.	.	X	.	X
Egypt 1996	10	.	.	.	X	.	X
Egypt 2006	10	X	.	.	X	.	.
El Salvador 1992	10	X	.	.	X	.	.
El Salvador 2007	10	X	.	.	X	.	.
Ethiopia 1984	10	X	.	.	X	.	.
Ethiopia 1994	10	X	.	.	X	.	X
Ethiopia 2007	10	X	.	.	X	.	X
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Sample	Sample fraction (%)	Systematic sampling	Complex stratification	Geographic clustering	Household clustering	Persons not organized into households	Differential weighting
		1	2	3	4	5	6
Fiji 1966	10	X	.	.	X	.	.
Fiji 1976	10	X	.	.	X	.	.
Fiji 1986	10	X	.	.	X	.	.
Fiji 1996	10	X	.	.	X	.	.
Fiji 2007	10	X	.	.	X	.	.
Fiji 2014	10	X	.	.	X	.	.
France 1962	5	X	.	.	X	.	.
France 1968	5	X	.	.	X	.	.
France 1975	5	X	.	.	X	.	.
France 1982	5	X	.	.	X	.	.
France 1990	4.2	.	.	X	X	.	.
France 1999	5	.	X	.	X	.	.
France 2006	33	.	X	X	X	.	X
France 2011	33	X	X	.	X	.	X
Germany 1970	5	X	.	.	.	X	.
Germany 1971	25	X	.	.	X	.	.
Germany 1981	25	X	.	.	X	.	.
Germany 1987	5	X	.	.	X	.	.
Ghana 1984	10	X	.	.	X	.	.
Ghana 2000	10	X	.	.	X	.	.
Ghana 2010	10	X	.	.	X	.	.
Greece 1971	10	X	.	.	X	.	.
Greece 1981	10	X	.	.	X	.	.
Greece 1991	10	X	.	.	X	.	.
Greece 2001	10	X	.	.	X	.	.
Greece 2011	10	X	.	.	X	.	.
Guatemala 1964	5	.	.	.	X	.	.
Guatemala 1973	6	.	.	.	X	.	.
Guatemala 1981	5	.	.	.	X	.	.
Guatemala 1994	10	X	.	.	X	.	.
Guatemala 2002	10	X	.	.	X	.	.
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Sample	Sample fraction (%)	Systematic sampling	Complex stratification	Geographic clustering	Household clustering	Persons not organized into households	Differential weighting
		1	2	3	4	5	6
Guinea 1983	10	X	.	.	X	.	.
Guinea 1996	10	X	.	.	X	.	.
Haiti 1971	10	X	.	.	X	.	.
Haiti 1982	2.5	X	.	.	X	.	.
Haiti 2003	10	X	.	.	X	.	.
Honduras 1961	1	.	.	.	.	X	.
Honduras 1974	10	.	.	.	X	.	.
Honduras 1988	10	X	.	.	X	.	.
Honduras 2001	10	X	.	.	X	.	.
Hungary 1970	5	X	.	.	X	.	.
Hungary 1980	5	X	.	.	X	.	.
Hungary 1990	5	X	.	.	X	.	.
Hungary 2001	5	X	.	.	X	.	.
Hungary 2011	5	X	.	.	X	.	.
India 1983	0.09	.	.	X	X	.	X
India 1987	0.09	.	.	X	X	.	X
India 1993	0.07	.	.	X	X	.	X
India 1999	0.07	.	.	X	X	.	X
India 2004	0.06	.	.	X	X	.	X
India 2009	0.04	.	X	.	X	.	X
Indonesia 1971	0.5	.	X	X	X	.	X
Indonesia 1976	0.2	.	X	X	X	.	X
Indonesia 1980	5	.	.	X	X	.	X
Indonesia 1985	0.4	.	.	X	X	.	X
Indonesia 1990	0.5	.	.	X	X	.	X
Indonesia 1995	0.4	.	.	X	X	.	X
Indonesia 2000	10	X	.	.	X	.	.
Indonesia 2005	0.5	.	.	X	X	.	X
Indonesia 2010	10	X	.	.	X	.	.
Iran 2006	2	.	X	.	X	.	X
Iran 2011	2	.	X	.	X	.	X
Iraq 1997	10	X	.	.	X	.	X
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Sample	Sample fraction (%)	Systematic sampling	Complex stratification	Geographic clustering	Household clustering	Persons not organized into households	Differential weighting
		1	2	3	4	5	6
Ireland 1971	10	X	.	.	X	.	.
Ireland 1979	10	X	.	.	X	.	.
Ireland 1981	10	X	.	.	X	.	.
Ireland 1986	10	X	.	.	X	.	.
Ireland 1991	10	X	.	.	X	.	.
Ireland 1996	10	X	.	.	X	.	.
Ireland 2002	10	X	.	.	X	.	.
Ireland 2006	10	X	.	.	X	.	.
Ireland 2011	10	.	.	.	X	.	.
Israel 1972	10	X	.	.	X	.	.
Israel 1983	10	X	.	.	X	.	.
Israel 1995	10	X	.	.	X	.	.
Italy 2001	5	X	.	.	X	.	.
Italy 2011	5	.	.	.	X	.	.
Italy 2011-2018 LF Surveys	~ 0.2	.	X	X	X	.	X
Jamaica 1982	10	X	.	.	X	.	.
Jamaica 1991	10	X	.	.	X	.	.
Jamaica 2001	10	.	.	X	X	.	X
Jordan 2004	10	X	.	.	X	.	.
Kenya 1969	6	X	.	.	X	.	X
Kenya 1979	6.7	.	.	.	.	X	X
Kenya 1989	5	X	.	.	X	.	.
Kenya 1999	5	X	.	.	X	.	.
Kenya 2009	10	X	.	.	X	.	.
Kyrgyz Republic 1999	10	X	.	.	X	.	.
Kyrgyz Republic 2009	10	X	.	.	X	.	.
Laos 2005	10	X	.	.	X	.	.
Lesotho 1996	10	X	.	.	X	.	.
Lesotho 2006	10	X	.	.	X	.	.
Liberia 1974	10	.	X	.	.	X	.
Liberia 2008	10	X	.	.	X	.	.
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Sample	Sample fraction (%)	Systematic sampling	Complex stratification	Geographic clustering	Household clustering	Persons not organized into households	Differential weighting
		1	2	3	4	5	6
Malawi 1987	10	X	.	.	X	.	.
Malawi 1998	10	X	.	.	X	.	.
Malawi 2008	10	X	.	.	X	.	.
Malaysia 1970	2	X	.	.	X	.	.
Malaysia 1980	2	X	.	.	X	.	.
Malaysia 1991	2	X	.	.	X	.	.
Malaysia 2000	2	X	.	.	X	.	.
Mali 1987	10	X	.	.	X	.	.
Mali 1998	10	X	.	.	X	.	.
Mali 2009	10	X	.	.	X	.	.
Mexico 1960	1.5	.	.	.	.	X	.
Mexico 1970	1	X	.	.	X	.	.
Mexico 1990	10	X	.	.	X	.	.
Mexico 1995	0.4	.	.	X	X	.	X
Mexico 2000	10.6	.	.	X	X	.	X
Mexico 2005	10	.	X	.	X	.	.
Mexico 2010	10	.	.	X	X	.	X
Mexico 2015	9.5	.	.	X	X	.	X
Mongolia 1989	10	.	.	X	X	.	X
Mongolia 2000	10	X	.	.	X	.	.
Morocco 1982	5	X	.	.	X	.	.
Morocco 1994	5	X	.	.	X	.	.
Morocco 2004	5	X	.	.	X	.	.
Mozambique 1997	10	X	X	.	X	.	.
Mozambique 2007	10	X	.	.	X	.	.
Nepal 2001	9	.	X	X	X	.	X
Nepal 2011	12	X	.	X	X	.	.
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Sample	Sample fraction (%)	Systematic sampling	Complex stratification	Geographic clustering	Household clustering	Persons not organized into households	Differential weighting
		1	2	3	4	5	6
Netherlands 1960	1.2	.	.	.	.	X	X
Netherlands 1971	1.2	.	.	.	.	X	X
Netherlands 2001	1.2	.	.	.	.	X	X
Netherlands 2011	2.5	.	.	.	.	X	X
Nicaragua 1971	10	X	.	.	X	.	.
Nicaragua 1995	10	X	.	.	X	.	.
Nicaragua 2005	10	X	.	.	X	.	.
Nigeria 2006-07	0.6	.	X	X	X	.	X
Nigeria 2007-08	0.6	.	X	X	X	.	X
Nigeria 2008-09	0.7	.	X	X	X	.	X
Nigeria 2009-10	0.5	.	X	X	X	.	X
Nigeria 2010-11	0.5	.	X	X	X	.	X
Pakistan 1973	2	.	.	X	X	.	X
Pakistan 1981	10	.	.	.	.	X	X
Pakistan 1998	10	X	.	.	X	.	.
Palestine 1997	10	X	.	.	X	.	X
Palestine 2007	10	X	.	.	X	.	X
Panama 1960	5	.	X	.	X	.	.
Panama 1970	10	.	.	.	X	.	.
Panama 1980	10	X	.	.	X	.	X
Panama 1990	10	X	.	.	X	.	.
Panama 2000	10	X	.	.	X	.	.
Panama 2010	10	X	.	.	X	.	.
Papua New Guinea 1980	10	X	.	.	X	.	.
Papua New Guinea 1990	10	X	.	.	X	.	.
Papua New Guinea 2000	10	X	.	.	X	.	.
Paraguay 1962	5	X	.	.	X	.	.
Paraguay 1972	10	X	.	.	X	.	.
Paraguay 1982	10	X	.	.	X	.	.
Paraguay 1992	10	X	.	.	X	.	.
Paraguay 2002	10	X	.	.	X	.	X
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Sample	Sample fraction (%)	Systematic sampling	Complex stratification	Geographic clustering	Household clustering	Persons not organized into households	Differential weighting
		1	2	3	4	5	6
Peru 1993	10	X	.	.	X	.	.
Peru 2007	10	X	.	.	X	.	.
Philippines 1990	10	.	.	X	X	.	X
Philippines 1995	10	X	.	.	X	.	.
Philippines 2000	10	.	.	X	X	.	X
Philippines 2010	10	X	.	.	X	.	X
Poland 1978	10	X	.	.	X	.	.
Poland 1988	10	X	.	.	X	.	.
Poland 2002	10	X	.	.	X	.	.
Poland 2011	10	X	.	.	X	.	.
Portugal 1981	5	X	.	.	X	.	.
Portugal 1991	5	X	.	.	X	.	.
Portugal 2001	5	X	.	.	X	.	.
Portugal 2011	5	X	.	.	X	.	.
Puerto Rico 1970	1	.	X	.	X	.	.
Puerto Rico 1980	5	.	X	.	X	.	.
Puerto Rico 1990	5	.	X	.	X	.	X
Puerto Rico 2000	5	.	X	.	X	.	X
Puerto Rico 2005	1	.	X	.	X	.	X
Puerto Rico 2010	1	X	.	.	X	.	X
Romania 1977	10	X	.	.	X	.	.
Romania 1992	10	X	.	.	X	.	.
Romania 2002	10	X	.	.	X	.	.
Romania 2011	10	X	.	.	X	.	.
Russia 2002	5	X	.	.	X	.	.
Russia 2010	5	X	.	.	X	.	.
Rwanda 1991	10	X	.	.	X	.	.
Rwanda 2002	10	X	.	.	X	.	.
Rwanda 2012	10	.	.	.	X	.	.
Saint Lucia 1980	10	X	.	.	X	.	.
Saint Lucia 1991	10	X	.	.	X	.	.
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Sample	Sample fraction (%)	Systematic sampling	Complex stratification	Geographic clustering	Household clustering	Persons not organized into households	Differential weighting
		1	2	3	4	5	6
Senegal 1988	10	X	.	.	X	.	.
Senegal 2002	10	X	.	.	X	.	.
Sierra Leone 2004	10	X	.	.	X	.	.
Slovenia 2002	10	X	.	.	X	.	.
South Africa 1996	10	X	.	.	X	.	X
South Africa 2001	10	X	.	.	X	.	X
South Africa 2007	2	.	.	X	X	.	X
South Africa 2011	8.6	X	X	.	X	.	X
South Sudan 2008	7	.	X	X	X	.	X
Spain 1981	5	.	X	.	X	X	X
Spain 1991	5	X	.	.	X	.	X
Spain 2001	5	X	.	.	X	.	.
Spain 2011	10	X	.	.	X	.	X
Spain 2005-2018 LF Surveys	~ 0.35	.	X	X	X	.	X
Sudan 2008	16.6	.	X	X	X	.	X
Switzerland 1970	5	X	.	.	X	.	.
Switzerland 1980	5	X	.	.	X	.	.
Switzerland 1990	5	X	.	.	X	.	.
Switzerland 2000	5	X	.	.	X	.	.
Tanzania 1988	10	.	.	X	X	.	X
Tanzania 2002	10	.	.	X	X	.	X
Tanzania 2012	10	.	X	.	X	.	X
Thailand 1970	2	.	X	.	X	.	X
Thailand 1980	1	.	X	.	X	.	X
Thailand 1990	1	.	.	X	X	.	X
Thailand 2000	1	.	.	X	X	.	X
Togo 1960	10	X	.	.	X	.	.
Togo 1970	1	.	.	.	X	.	.
Togo 2010	10	X	.	.	X	.	X
Trinidad & Tobago 1970	10	X	.	.	X	.	.
Trinidad & Tobago 1980	10	X	.	.	X	.	.
Trinidad & Tobago 1990	10	X	.	.	X	.	.
Trinidad & Tobago 2000	10	X	.	.	X	.	.
Trinidad & Tobago 2011	8.8	X	.	.	X	.	.
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Sample	Sample fraction (%)	Systematic sampling	Complex stratification	Geographic clustering	Household clustering	Persons not organized into households	Differential weighting
		1	2	3	4	5	6
Turkey 1985	5	X	.	.	X	.	.
Turkey 1990	5	X	.	.	X	.	.
Turkey 2000	5	X	.	.	X	.	.
Uganda 1991	10	.	.	X	X	.	X
Uganda 2002	10	X	.	.	X	.	.
Ukraine 2001	10	X	.	.	X	.	.
United Kingdom 1991	1	X	.	.	X	.	.
United Kingdom 2001	3	.	.	.	.	X	.
United States 1960	1	.	X	.	X	.	.
United States 1970	1	.	X	.	X	.	.
United States 1980	5	.	X	.	X	.	.
United States 1990	5	.	X	.	X	.	X
United States 2000	5	.	X	.	X	.	X
United States 2005	1	.	X	.	X	.	X
United States 2010	1	.	X	.	X	.	X
United States 2015	1	.	X	.	X	.	X
Uruguay 1963	10	X	.	.	X	.	.
Uruguay 1975	10	X	.	.	X	.	.
Uruguay 1985	10	X	.	.	X	.	.
Uruguay 1996	10	X	.	.	X	.	.
Uruguay 2006	8.4	.	X	X	X	.	X
Uruguay 2011	10	X	.	.	X	.	.
Venezuela 1971	10	.	X	.	X	.	X
Venezuela 1981	10	X	.	.	X	.	.
Venezuela 1990	10	.	X	.	X	.	X
Venezuela 2001	10	X	.	.	X	.	.
Vietnam 1989	5	.	X	X	X	.	X
Vietnam 1999	3	.	X	X	X	.	X
Vietnam 2009	15	.	X	X	X	.	X
Zambia 1990	10	X	.	.	X	.	.
Zambia 2000	10	X	.	.	X	.	.
Zambia 2010	10	X	.	.	X	.	.
Zimbabwe 2012	5	.	.	.	X	.	.

Systematic samples (Column 1): Most IPUMS samples are systematic household samples, in which every nth household is selected from the full population. Although explicit geographic stratification is sometimes employed, the sampling fraction is constant in all strata. Weights should be applied in a minority of samples (see column 6) and analysts should adjust standard errors for the clustering of persons within households (see column 4). Analyses that follow these guidelines should produce accurate estimates of standard errors.

Complex stratified samples (Column 2): Also common are household samples drawn using complex stratification techniques: either disproportionate sampling of geographic areas (e.g. oversampling rural areas) or non-geographic stratification (using demographic or socioeconomic characteristics). Because complex stratification is typically employed to improve the precision of estimates for small populations, standard variance techniques should generally yield conservative estimates. Weights are generally required and analysts should adjust standard errors for the clustering of persons within households (see column 4).

Cluster samples (Columns 3 and 4): Most IPUMS samples are samples of households and are therefore clustered by household (column 4). Some samples use geographical areas as the primary sampling unit in clustered samples, with households sampled in a second stage (column 3). Thus, clustering occurs at two levels: enumeration areas and households. Cluster sampling by geographic area occurs more commonly for sample surveys or long form censuses than for standard censuses and often involves complex stratification. Because standard estimation techniques generally underestimate variances in clustered samples, researchers must use caution when interpreting standard errors in these samples, particularly for variables that are likely to be highly correlated within enumeration areas. Researchers should employ weights and adjust for household level clustering.

Persons not organized into households (Column 5): This column identifies censuses that sampled individual person records rather than entire households. Because persons are not clustered in households, standard variance estimates should generally be accurate. Some statistical agencies employed complex stratification techniques, and in these samples standard error estimates are likely conservative. Researchers should use weights when necessary.

Sample weights (Column 6): This column identifies samples that require the use of household and person weights to yield accurate population estimates. These weights adjust for complex stratification and clustered sampling designs, as well as census underenumeration.

Sampling Error Estimation

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