Methodological Notes – Population Module

Updated: May 2011

Concepts and Definitions

In assessing the health of a population, accurate enumeration of the population is needed to provide the denominator for the rates and proportions which constitute many health indicators.

Most health indicators are aggregated on an annual basis, with the number of events occurring in a year (numerator) divided by the mean population of that period (year). Depending on how population is reported by the particular statistical agency:

Mean population for year xxxx

= population on July 1 for year xxxx; or

= [population on Jan 1 for year xxxx + population on Jan 1 for year (xxxx+1)] / 2; or

= [population on Dec 31 for year xxxx + population on Dec 31 for year (xxxx-1)] / 2

As most health events tend to vary according to age and sex, the age-sex distribution of a population is needed to compute age-specific and age-standardized rates and proportions. Age data in the table are aggregated in 5-year age-groups (0-4, 5-9, …80-84, 85+), which can be combined into a smaller number of age groups (0-4, 5-14, 15-24, 25-44, 45-64, and 65+) if needed.

The circumpolar region is known for its vast expanses and small populations, reflected in a generally low population density, calculated as:

Population density = (mean annual population) / (land area in sq.km)

This is expressed as persons per sq.km. The concept of “land” area excludes inland waters and coastal territorial waters. However, in the Arctic, there are also large, uninhabitable ice-covered areas. Strictly speaking these areas should also be excluded, but to determine their exact extent would require sophisticated satellite imaging techniques. In the case of Greenland, if only ice-free land area is used in the calculation of population density (about 410, 450 sq.km), the population density would increase from 0.03 to 0.14 per sq.km. Land area is rounded to the nearest 10 sq km, and for Russia, 100 sq km.

Data Sources and Limitations

There are two sources of information on population – the census and population registry. Both are in use in the circumpolar countries.

The Nordic countries have well established population registries, which are continuously updated, and thus capable of generating the precise population of the country and its regions at a point in time, such as the beginning of the year (January 1, as in the case of Denmark, Greenland, Faroe Islands, and Norway), or at year end (Dec 31, as in the case of Finland, Iceland and Sweden). Where mean population is not published, it can be obtained by averaging the Jan 1 or Dec 31 populations of two successive years. Decennial population and housing censuses are also conducted in Norway and Finland (but discontinued in other Nordic countries), primarily to obtain information about living conditions and other characteristics of the population. Other countries rely on special-purpose sample surveys.

Canada, United States and Russia rely on periodic censuses. Canadian censuses are conducted every 5 years in the years ending in “1” and “6”. In the United States, a census is conducted once every 10 years in the year ending in “0”. Russian censuses are irregular – the last Soviet census was completed in 1989, and the first post-Soviet census in 2002 and the second one in 2010. In the “intercensal” years, these jurisdictions produce annual estimates of the population, taking into account data on births, deaths, and migrations. It is these annual estimates (for all years including census years) that are used in CircHOB. They are preferable to the raw census counts as denominators.

United States

Population data are from the National Center for Health Statistics: vintage 2009 bridged-race population estimates, accessed from CDC Wonder. There are slight differences in population counts for the same year when different vintages are used. When a new vintage is released, all previous years’ data are revised. For explanation of bridged-race population estimates, see documentation. Land area data are from US Census Bureau QuickFacts, converted from square miles.

Canada

Population data are from Statistics Canada: CANSIM Table 051-0001.

Note: there is a fee per data series if accessed from the public website; free if accessed from designated depository libraries. A list of depository libraries is available from here.

For description of estimation methods, see Population and Family Estimation Methods at Statistics Canada, Cat.No.91-528-XIE.

2000-05 data are final intercensal, 2006-07 final postcensal, and 2008-09 updated postcensal estimates.

Land area data are from Statistics Canada: 2001 Census on-line highlight tables (Cat. No. 93F0051XIE).

Greenland

Population data are from Statistics Greenland, calculated from Stat Bank file BEEST1.

Mid-year population of year xxxx = mean of [1-Jan-xxxx] and [1-Jan-(xxxx+1)]

Land area data are from Statistics Greenland: Greenland in Figures 2010.

Faroe Islands

Population data are from Statistics Faroe Islands, calculated from Table FOLK1AR.

Mid-year population of year xxxx = mean of [1-Jan-xxxx] and [1-Jan-(xxxx+1)]

Land area data are from Statistics Faroe Islands > Key Figures

Iceland

Population data are from Statistics Iceland: File MAN 08000.

> Mid-year population by sex and age 1841-

Land area data are from Statistics Iceland > Geography and Environment > Geographical Data

Denmark

Population data are from Statistics Denmark: Statbank Table BEF6 [2000-06]; BEF607 [2007-08]; FOLK1 [2009].

> Population and Elections > Population in Denmark > Show also discontinued tables

Land area data from Statistics Denmark: Denmark Statistical Yearbook 2010, Table 1.

Norway

Population data are from Statistics Norway, calculated from StatBank Table 7459

> 02.01 Population structure > 02.01.10 Population > 07459

Mid-year population of year xxxx = mean of [1-Jan-xxxx] and [1-Jan-(xxxx+1)]

Land area data are from Statistics Norway: Statistical Yearbook of Norway 2010, Table 19.

Sweden

Population data are from Statistics Sweden: Statistical Database.

> Population statistics > Mean population > Mean population by region, marital status, age and sex, 1969 – > Select:

  • Mean population for Sweden by marital status and sex, 1969 -
  • Mean population by county by marital status and sex, 1969 -

Land area data are from Statistics Sweden: Finding Statistics > Statistical Database > Environment > Land and water area

Finland

Population data are from Statistics Finland: PX-Web database.

The Finnish version of the database has a wider selection of regional groupings. The English version has data for the whole country and breakdown by makunta only, and requires data aggregation to generate data at lääni level (replaced by AVI as of January 1, 2010).

> Väestö iän (1-v.) ja sukupuolen mukaan alueittain 1980 – [population by age (1-year), sex and region] > Change Alue [area] to Aluehallintovirasto [AVI, state administrative agency] > Select Koko maa [whole country], Pohjois-Suomen AVI [=former Oulun lääni] and Lapin AVI [=former Lapin lääni]

Mid-year population of year xxxx = mean of [31-Dec-(xxxx-1) and [31-Dec-xxxx]

Land area data were from Statistical Yearbook of Finland 2010, Table 6

Population data are from Federal State Statistics Service [Rosstat]: only the Russian website contains the interactive database for regional data.

Mid-year population of year xxxx = mean of [1-Jan-xxxx] and [1-Jan-(xxxx+1)]

Data on age-sex distribution are not available from the interactive database, and must be extracted from statistical publications.

For 2000-04 data, the age-sex distribution of the population of Russia and regions as reported in the 2002 Census Report, vol 2, is applied to the total annual mean population.

For 2005-09 data for the Russian Federation, the midyear data are calculated from the January 1 estimates as reported in the Demographic Yearbook of Russia 2005 (Table 1.20), 2006 and 2007 (Table 1.9), 2008 and 2009 (Table 1.10). The Demographic Yearbook is bilingual, and current and back issues are available for download in Russian site only.

For 2005-09 regional data, the midyear data are calculated from the January 1 estimates as reported in Chiselennost’ naseleniia Rossiikoi Federatsii po polu i vozrastu: Statisticheski biulleten 2006, 2007, 2008, 2009 [Bulletin of the population of the Russian Federation by sex and age]. Only the most recent two years reports are posted; previous years’ reports are not archived.

Mid-year population of year xxxx = mean of [1-Jan-xxxx] and [1-Jan-(xxxx+1)]

Land area data are from Regiony Rossii: Sotsial’no-ekonomischeskie pokazateli 2007 [Regions of Russia: Socio-economic characteristics], Table 1.2.