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Population change - Methodology

I. Basic definition (of the statistical area of interest)

Statistics on population change includes demographic events with the effect on change in the size or structure of the population. These events are the birth of a child, death of a person, marriage, divorce, and change of permanent (or, in the case of foreigners, also temporary) residence. Demographic statistics of the Czech Republic traditionally includes also data on abortions, but the collection of these data is carried out by the Institute of Health Information and Statistics of the Czech Republic. Demographic statistics includes only events of citizens of the Czech Republic and foreigners with permanent residence in the Czech Republic, third-country nationals with temporary residence in the territory of the Czech Republic on the basis of a long-term visa (over 90 days) or a long-term residence permit, nationals of the EU Member States, Norway, Switzerland, Iceland, Liechtenstein and their family members with notified temporary residence in the territory of the Czech Republic, and foreigners with valid asylum status in the Czech Republic (see Population – Methodology).

II. Data sources

1.     Statistical surveys

(sources of statistical data on natural change, marriages, and divorces)

· Statistical report on marriage entry (Obyv 1-12)
  
the reporting unit is the registry office registering a marriage entry that occurred in its administrative district

· Statistical report on birth (Obyv 2-12)
  
the reporting unit is the registry office registering a birth that occurred in its administrative district

· Statistical report on death (Obyv 3-12)
   the reporting unit is the registry office registering a death that occurred in its administrative district

· Statistical report on divorce (Obyv 4-12)
   the reporting unit is the court dealing with relevant divorce proceedings

2.     Administrative data sources

(sources of statistical data on migration, cause of death, and abortions)

· Information System of Inhabitants Records
– for migration of Czech citizens

· Alien Information System (CIS)
– for migration of foreigners with valid permanent or temporary residence

· Report on examination of a deceased person (LPZ), or its relevant part defined by the Decree No 297/2012 Sb, as amended
for cause of death statistics

· Report on abortion
– for statistics on abortions

III. Statistical population and sample, imputations, and estimations of the non-covered part of the population

Given the statutory obligation to report demographic events (the reporting unit is obliged to register all events that occur in its administrative district (or are in its power), the data sets of demographic events are considered to be complete (exhaustive). Only data on the population of the Czech Republic are included in demographic statistics (see Section VI).

Besides events of residents of the Czech Republic occurring in the territory of the Czech Republic, marriages, births, and deaths of Czech citizens with permanent residence in the Czech Republic (at least one of the fiancés is a Czech citizen in the case of a marriage, and at least one of the parents of the child is a Czech citizen in the case of a birth) that occur abroad and are registered in the Czech Republic within a period that allows their inclusion into the statistics, are included in the statistics.

Data on births, deaths and marriages are included in statistics according to the date of the event, divorces according to the date of legal effect. In the case of migration data, the reference time is the date of reporting the change of address of residence to the competent authority. 

The age of a person at the time of the event is given in completed years, i.e. represents the age at the last birthday. In the case of the age of deceased infants, it is the age in completed days.

The statistics on demographic events is processed down to the level of municipalities, only in the case of the capital city of Prague down to the detail of individual basic settlement districts. However, with regard to personal data protection, the detail of published outputs for individual territorial units varies (e.g. the number of marriages in individual municipalities is not broken down into age units, etc.).

Marriages

The subject of marriage statistics is the number of legal marriages of residents of the Czech Republic (at least one of the fiancés was at the time of marriage entry a resident of the Czech Republic), for which the Czech Statistical Office received a statistical report on marriage entry from the reporting unit (registry office). The number of marriages includes both civil and (until 1949 and since 1 July 1992) religious marriages.

The following data are used for demographic statistics from the report on marriage entry: date of marriage, date of birth of the groom/bride, marital status of the groom/bride, address of registered residence of the groom/bride, citizenship of the groom/bride, education of the groom/bride, order of marriage of the groom/bride, and date of previous divorce or widowhood of the groom/bride. Based on the collected data, the CZSO calculates the age of the groom/bride at the time of marriage, and, in the case of marriages of higher than first order, the time elapsed since the divorce/widowhood.

In terms of the territorial breakdown of marriages, they are by default classified according to the place of residence of the groom (unless stated otherwise).

Divorces

The subject of divorce statistics is the number of legal dissolutions of marriages of residents of the Czech Republic (at least either man or woman was at the time of divorce a resident of the Czech Republic), for which the reporting unit (district court, the Brno Municipal Court for the Brno-City district; via the Ministry of Justice) sent data from the statistical report on divorce.

The following data are used for divorce statistics within the framework of demographic statistics: date of the legal effect of divorce, date of marriage, date of birth of the man/woman, address of the last common residence of the woman and man, the address of residence of the man/woman (since 2022), education of the man/woman, citizenship of the man/woman, the country of birth of the man/woman (since 2022), the number of (living) minor children, the petitioner of the divorce, the result of the divorce proceedings (since 2007, data are collected only on proceedings that ended in a marriage dissolution), order of the divorce of the man/woman, and the cause of the marriage breakdown on the part of the man and woman (if examined). Based on the collected data, the CZSO calculates the age of the man/woman at the time of divorce and the duration of the marriage at the time of its dissolution by divorce.

In terms of the territorial breakdown of divorces, they are classified by the last common place of residence of the man and woman; since 2022, classifications by place of residence of man and woman separately have been also available.

Births

The subject of birth statistics is the number of all births, both live births and stillbirths of residents of the Czech Republic (at least one of the parents is a resident of the Czech Republic), for which the Czech Statistical Office received a statistical report on birth from the reporting unit (registry office). The number of births does not include children whose mother has requested to be undisclosed in connection with childbirth (pursuant to Act No 20/1966 Sb, on Public Health Care, as amended by Act No 422/2004 Sb), and foundlings (with the unknown identity of mother).

The following data are used for demographic statistics from the report on birth: date of birth, sex, whether the child was born alive or stillborn, birth weight and birth length of the child, week of pregnancy, birth order (total, and in the current marriage from the perspective of mother), date of birth of the previous birth to the mother, marital status of the mother, address of registered residence of the mother, date of birth, education, citizenship, and (since 2012) country of birth of both parents, and date of marriage of the parents. For a child born to an unmarried woman, the data on the father are not always available. Based on the collected data, the CZSO calculates the age of the mother and father at childbirth, the time elapsed since the birth of the previous birth to the mother, the time elapsed since the marriage, and based on information on the citizenship of mother and father, the CZSO determines (derives) citizenship of child (when at least one of the parents has (at the time of childbirth) Czech citizenship, then the child is assigned Czech citizenship; when both parents are of foreign citizenship, then the child is assigned the citizenship of mother).

In most cases, statistical outputs are (only) for live births, which are one of the components of the natural change of the population. The distinction between live birth and stillbirth is based on the information provided in the report on birth, compliance with the definitions is assumed. At present, the definitions of live birth and stillbirth along with all cases of abortions are provided in the instructions for filling in the Report on examination of the deceased person (in the Decree No 297/2012 Sb, on the Report on Examination of the Deceased Person, as amended), for the purpose of filling in this report. Definitions of livebirth and stillbirth are also provided in EU legislation: a livebirth in Regulation (EU) No 1260/2013 of the European Parliament and of the Council on European statistics on demography; a stillbirth in the Commission Regulation (EU) No 328/2011 implementing Regulation (EC) No 1338/2008 of the European Parliament and of the Council on Community statistics on public health and health and safety at work, as regards statistics on causes of death, for the purposes of the respective regulations.

In terms of the territorial breakdown of births, they are classified by the place of residence of the mother at the time of childbirth (if the mother has not registered residence in the Czech Republic, by the place of residence of the father at the time of childbirth).

Deaths

The subject of death statistics is the number of all deceased residents of the Czech Republic, for which the Czech Statistical Office received a statistical report on death from the reporting unit (registry office). The number of deaths does not include persons of unknown identity.

The following data are used for demographic statistics from the report on death: date of death, date of birth, sex, marital status, address of (registered) residence, education, citizenship, and (since 2012) country of birth of the deceased, and in the case of a deceased person of marital status married, also the date of birth of the widowed. The place of death is taken from the Report of examination of the deceased person (in 2007–2012 it was information stated in the statistical report). Based on the collected data, the CZSO calculates the age of the deceased and the age of the widowed.

Deaths by cause of death

For the compilation of statistics on cause of death, the Institute of Health Information and Statistics of the Czech Republic (IHIS CR) transmits selected characteristics of the relevant part of the Report of examination of the deceased person (causes of death and related medical characteristics) to the CZSO. Until 2012, causes of death were collected by the CZSO through the registry offices via the statistical reports on death.

Causes of death are coded according to the decennial revisions of the International Statistical Classification of Diseases and Related Health Problems valid in the Czech Republic (for periods of validity of individual decennial revisions see section IX). Since 2009, updates of the 10th revision issued by the World Health Organization (WHO) have been implemented in the Czech Republic. The IHIS CR is responsible for the translation of the ICD-10 and its updates to Czech, and their implementation in the CR.

In statistical outputs, the data are tabulated according to the underlying cause of death which is defined by the WHO as the disease or injury which initiated the train of morbid events leading directly to death, or the circumstances of the accident or violence which produced the fatal injury. Since 2011, the CZSO has been using the programme for automated coding (IRIS) for the selection of the underlying cause of death.

Migration (immigrants, emigrants)

Migration refers to a change of the permanent residence, as for foreigners, it also refers to a change of temporary residence exceeding 90 days, across the border of a given territorial unit. Migration statistics compiled by the CZSO are based on the change of the municipality of residence; data on migration within the territory of a municipality are available only for the capital city of Prague (published down to the level of city districts). Migration statistics are processed separately for internal (within the territory of the Czech Republic) and international migration.

The following data from administrative data sources are used for demographic statistics: date of birth, sex, marital status, and citizenship of the migrant; the migration itself is specified by the date of change of the registered residence and the municipality of the previous and new residence (in the case of change of the residence in the territory of the Czech Republic; in the case of migration from/to abroad, no information on a country of origin/destination is available).

Note: The completeness and the quality of migration statistics depend on the completeness of reporting changes of address of residence by residents of the Czech Republic. For example, if a person does not report the termination of his or her residence in the Czech Republic to the competent authorities when moving abroad, this event is not recorded in the administrative data source, and consequently in migration statistics and population balance (in fact emigrated person remains in the annual population figures obtained by the balance (and overestimates them) until the new census, when he or she is not be enumerated, or (in the case of foreigners) until the residence permit expires).

Abortions

Data on abortions of women residing in the Czech Republic that occur in the territory of the Czech Republic are provided to the CZSO by the Institute of Health Information and Statistics of the Czech Republic (IHIS CR) in the form of a set of individual records on abortions registered in the reference year. The CZSO publishes data without changes, i.e. including classification of the collected characteristics used by IHIS CR (it concerns e.g. breakdown of marital status and education of a woman, which is more detailed compared to the common classifications used by the CZSO). Definitions of all cases of abortion are provided in the instructions for filling in the Report of examination of the deceased person (in Decree No 297/2012 Sb, on the Report of Examination of the Deceased Person, as amended).

In the CZSO outputs, abortions are broken down by date of abortion, type of abortion, gestational age of a foetus, age, marital status, citizenship, and education of the woman, the number of previous abortions and live births to the woman; territorially are classified by the place of residence of the woman.

IV. Overview of key indicators

The indicators are used at the national and regional level (most of them), and for various periods. However, the reliability of the indicator for small territorial units/periods may be affected by the low number of events that occurred in the unit or by the small population size of the unit. The period mostly used in demographic statistics is a calendar year.

Natural change (natural increase or decrease)
The difference between the number of live births and the number of deaths in the reference period.

Net migration
The difference between the number of immigrants to a given territorial unit and the number of emigrants from it in the reference period.

Population change (total increase or decrease)
The sum of natural change and net migration in the reference period.

Crude (marriage/divorce/birth/abortion/death/migration rate) rates
The number of given demographic events per total mid-period population (i.e. at the middle of the reference period). They are usually expressed per 1,000 population.

Sex-age-specific (marriage/divorce/fertility/abortion/death/migration) rates
The number of given demographic events of persons of a given age (age interval) per mid-period population (usually per 1,000 population) of that age (age interval).

Total first marriage rate
The proportion of the population (of men/women) who would enter into the first marriage before their 50th birthday, provided that age-specific marriage, mortality, and migration rates of the single population observed in a reference year remained unchanged. It is the output indicator of one-decrement nuptiality life tables (see Section IX). The indicator is only available at the national level.

The mean age at marriage
The average age at marriage can be based on the distribution of age-specific marriage rates, or on the distribution of absolute numbers of marriages by age of the bride/groom (see methodological notes in the individual publications for a method of calculation used). In the annual time series at the national level, the mean age of men/women at first marriage is based on the distribution of table numbers of first marriages by age from one-decrement nuptiality life tables.

Total divorce rate
The proportion of marriages that would terminate in divorce, provided that the divorce rates by the duration of the marriage of a reference year remained unchanged. Divorce rates by the duration of marriage express the number of divorces of a given duration of marriage per number of marriages that occurred before the relevant number of years.

The average age at divorce can be based on the distribution of age-specific divorce rates, or on the distribution of absolute numbers of divorces by age of the man/woman (see methodological notes in the individual publications for a method of calculation used).

Secondary sex ratio
The ratio of the number of live-born boys to the number of live-born girls (usually per 100 girls) in a reference period.

Total fertility rate
The average number of children that would be born alive to a woman provided that age-specific fertility rates of a reference year remained unchanged during her childbearing period (age 15–49 years).

Age-specific fertility rate
The number of live births to women in a given age (age group) per 1,000 mid-year population of women in that age (age group). The average age of women at childbirth can be based on the distribution of the age-specific fertility rates, or on the distribution of absolute numbers of live births by age of the woman (see methodological notes in the individual publications for a method of calculation used).

Gross reproduction rate
The average number of live-born daughters that would be born to a woman provided that the age-specific fertility rates of a reference year remained unchanged during her childbearing period (age 15–49 years).

Net reproduction rate
The average number of live-born daughters that would be born to a woman and live to the age of their mother at the time of childbirth provided that the age-specific intensities of fertility and mortality of a reference year remained unchanged during her childbearing period (age 15–49 years). The probability of surviving to the age of the mother is based on mortality tables.

Total abortion rate
The average number of abortions that a woman would have provided that age-specific abortion rates of a reference year remained unchanged during her childbearing period (age 15–49 years). Similarly, total legally induced abortion rate and total spontaneous abortion rate are defined as the average number of abortions of a given type per woman.

The average age of women at abortion can be based on the distribution of the age-specific abortion rates, or on the distribution of absolute numbers of abortions by age of the woman (see methodological notes in the individual publications for a method of calculation used).

Stillbirth rate
The proportion of stillbirths of total births in a reference period (usually per 1,000 total births).

Infant mortality rate
The ratio of the number of deaths aged under 1 year to the number of live births in a reference period (usually per 1,000 total births).

Neonatal mortality rate
The ratio of the number of deaths of infants aged under 28 days to the number of live births in a reference period (usually per 1,000 live births).

The perinatal mortality rate
The ratio of the number of stillbirths and deaths of infants aged under 7 days to the number of total births in a reference period (usually per 1,000 births).

Life expectancy
The average number of years an x-year-old individual can expect to live provided that age-specific mortality conditions of a reference period remained unchanged. It is a main indicator of mortality life tables (for details see section IX). Due to the different mortality level by sex, the life expectancy is calculated separately for men and women.

Volume of international migration (gross international migration)
The sum of immigrants from abroad and emigrants abroad in a reference period.

Volume of internal migration
The number of all registered changes of place of residence within a given territorial unit in a reference period. The volume of internal migration of a higher territorial unit is defined as the sum of the volumes of internal migration of relevant lower territorial units and volumes of internal migration among these lower territorial units.

V. Data revisions

Data published as provisional are revised during the year by updating all monthly population data since the beginning of the year once every three months when new provisional data are released for the last quarter (i.e. when the next news release ‘Population change’ and related publication ‘Population of the Czech Republic’ are issued). Data for a reference year are considered to be final 120 days after the end of the reference period (except for causes of death which are available from 30 June of the following year). The CZSO does not revise the final results of demographic statistics retrospectively.

VI. Comparability

1. Comparability over the years

Since 1 May 2004, all data have been referred to citizens of the Czech Republic and foreigners with permanent residence in the Czech Republic, third-country nationals with temporary residence in the territory of the Czech Republic on the basis of a long-term visa (over 90 days) or a long-term residence permit, nationals of the EU Member States, Norway, Switzerland, Iceland, Liechtenstein and their family members with notified temporary residence in the Czech Republic, and foreigners with valid asylum status in the Czech Republic. Until 2000, only events of residents with permanent residence in the Czech Republic (irrespective of their citizenship) were included. Since 2001, following the 2001 Census of population, houses and dwellings, the data have newly also included events of foreigners with a visa for a stay over 90 days and foreigners with asylum status.

The regional breakdown of the results of demographic statistics in a reference year corresponds to the territories valid as of 1 January of that year. If a territorial change occurs during the year (as of a date other than 1 January), this change will be reflected in the statistics for the following year for the first time. Thus, data in the time series for a certain territorial unit may not be fully comparable in the case of territorial changes. The time series of the comparable data on the population stocks and population change of individual territorial units (which refer to the same territorial structure for all years of the time series) are presented in the demographic yearbooks of the (different types of) territorial units (Demographic Yearbook of Regions, Demographic Yearbook of Districts, Demographic Yearbook of Towns, Demographic Yearbook of Administrative Districts of Municipalities with Extended Powers, and Demographic Yearbook of Administrative Districts of Municipalities with Authorised Municipal Authority). 

The data on demographic events always respect the legislation effective in the year when the event occurs, with the definitions of individual events changing over the years (see below and section IX).

Marriages

The citizenship of a groom/bride has been surveyed since 1995, until 1994 the ethnicity was surveyed.

Since 2007, the education of a groom/bride has been collected on a voluntary basis (a separate category ‘not identified’ has occurred in the statistics since 2008). Since 2015, the surveyed levels of the highest completed education of a groom/bride have been expanded to include a separate category for tertiary technical education.

Since 2013, in consequence of the modification of the Marriage Questionnaire (the document of registry offices, which the registry offices use also for completing the statistical report on marriage entry), data on the order of marriage of divorced or widowed fiancés and the date of the last divorce or widowhood have not been available for all fiancés anymore).

Divorces

Until 2006, divorces were broken down into calendar months according to the date of sending the report on divorce; since 2007, the month in which the divorce became legally effective has been a determining criterion. Based on this time information on divorce and the date of marriage, the duration of the marriage at the time of divorce is calculated.

Citizenship has been surveyed since 1995, until 1994 ethnicity was surveyed.

Since 2007, education has been collected on a voluntary basis (a separate category ‘not identified’ occurs has occurred in the statistics since 2007). Since 2022, the surveyed levels of the highest completed education of the man/woman have been expanded to include a separate category for tertiary technical education.

A joint divorce petition has been possible (according to the § 755-758 of the Civil Code) since 1 January 2014, but this option was implemented into statistics in 2015.

Births

In 1949, 1953, 1965, 1988 and 2012, the definition of a live birth/stillbirth changed (see Section IX for more details).

In accordance with Regulation (EU) No 1260/2013 of the European Parliament and of the Council on European demographic statistics, the methodology for reporting birth order changed in 2014. Until 2013, the birth order reflected all children born to a woman, i.e. including stillbirths; since 2014, the birth order has been determined only from and for live births of a woman.

Since 2007, the education has been collected on a voluntary basis (since that year a separate category ‘not identified’ has occurred in the statistics). Since 2015, the surveyed levels of the highest completed education of the mother/father of the child have been expanded to include a separate category for tertiary technical education.

The citizenship has been surveyed since 1995, with only the citizenship of the child being collected in 1995–2011, and the citizenship of the mother and the father being collected since 2012 from which the citizenship of the child is determined for statistical purposes (see Section III). Until 1994 the ethnicity of the father and mother of the child was surveyed.

Until 2007, data on fathers of children born outside marriage were not covered in the statistics.

Deaths

Citizenship has been surveyed since 1995, until 1994 ethnicity was surveyed.

Since 2007, the education has been collected on a voluntary basis (since that year a separate category ‘not identified’ has occurred in the statistics). Since 2013, the categories of marital status and education of the deceased used in the CZSO statistics have been in accordance with the Report on examination of the deceased person (the classifications are more detailed compared to the common codes of the CZSO which are used in the demographic statistics).

Migration

The comparability of data on migration (especially international migration) over the years is partly affected by changes in data sources.

Until 2000, migration statistics were based on data collection via statistical reports (Obyv 5-12 Report on migration). In 2001–2004, the statistical Report on migration was the source for migration statistics of Czech citizens (with residence registration offices as reporting units), and data on the migration of foreigners were provided by the Directorate of the Foreign Police Service from its information system.

Since 2005, all reports on migration have been replaced by administrative data from the Ministry of the Interior of the Czech Republic. The Information System of Inhabitants Records is the source of data on the migration of Czech citizens and in the period from 2008 to June 2012 was the source of data for all migration statistics (i.e. including migration of foreigners). The Foreigners Information System is the data source for the migration of foreigners (both across state borders and within the country), except for the aforementioned period from the beginning of 2008 to mid-2012.

Citizenship of migrants has been surveyed since 1995, until 1994 ethnicity was surveyed.

Until 2004, the reason for migration and the education of the migrant were also surveyed; the end of the collection of these characteristics was related to the change in data sources of the migration statistics.

Abortions

Abortion statistics has been kept in the CR since 1953, detailed statistics on all types of abortions since 1958 in connection with the entry into force of the Act No 68/1957 Sb, on Induced Termination of Pregnancy. The definition of abortion changed in 1965, 1988 and 2012 (see Section IX and www.uzis.cz for more details). 

2. Comparability with other data of the same nature

Data on births, deaths and abortions published by the Institute of Health Information and Statistics of the Czech Republic (www.uzis.cz) may be based on other data sources (health statistics of the IHIS CR) and thus may differ from the data published by the CZSO.

3. International comparability

Data on natural change are provided by the Member States to Eurostat in accordance with the Regulation (EU) No 1260/2013 on European demographic statistics. According to it, the Member states shall provide Eurostat with data on births and deaths by their usual residence at the reference time. However, if the place of usual residence cannot be established, the usual residence can be taken to mean the place of legal or registered residence (applied for data for the Czech Republic). Data on other demographic events are provided to Eurostat on a voluntary basis. For more details see Marriages and divorces (europa.eu), Fertility (national level) (demo_fer) (europa.eu), Mortality (national level) (europa.eu). In the case of stillbirth statistics, the data published by the CZSO and Eurostat differ due to a different definition applied.

The provision of data on international migration to Eurostat follows the Regulation (EC) No 862/2007 of the European Parliament and of the Council on Community statistics on migration and international protection; see Immigration (migr_immi) (europa.eu) for more details. These data differ from data published by the CZSO within the framework of demographic statistics due to a different definition.

VII. Seasonal adjustment

Data on demographic events are not subject to seasonal adjustment.

VIII. Dissemination

All national outputs are available on the CZSO website in the Catalogue of Products, and most outputs can also be found in Public Database.

The most up-to-date data on the number of demographic events of the population of the Czech Republic, individual cohesion regions, regions, districts, and (since 2022) administrative districts of municipalities with extended powers are published – as preliminary – on a quarterly basis, on the 73rd day after the end of the quarter, and the 80th day after the end of the year (for specific dates see Catalogue of Products), in the data set Population of the Czech Republic.

Final data on the number of demographic events and their breakdowns by various characteristics are published in the source publications of the demographic statistics, which has been published under the title Demographic Yearbook of the Czech Republic since 2005. Demographic Handbook contains long-term time series of the data on population; time series of the main demographic data are presented also in the Population time series.

Individual breakdowns of the data on demographic events can be obtained on request through the CZSO Information Services (infoservis@csu.gov.cz).

IX. Additional methodological information and external links

Quality report(s)

Available at Population - Reports on quality | CZSO

Legislation

The Czech Statistical Office performs the State Statistical Service on the basis of Act No 89/1995 Sb, on the State Statistical Service. Its scope is defined in § 4, respectively § 7 of this Act.

The territorial breakdown of the Czech Republic follows Constitutional Act No 347/1997 Sb, on the Establishment of Higher Territorial Self-Governing Units (regions), as amended, on the Act No 387/2004 Sb, on Changes in Regions Boundaries, as amended, and on the Act No 51/2020 Sb, on the Territorial Administrative Division of the State. The CZ-NUTS classification and other territorial code lists for the territory of the Czech Republic are also used (see Main territorial code lists for the territory of the Czech Republic and CZ-NUTS classification (in Czech only).