Glossary

Time lived since birth.
Age can be calculated in a number of ways:

Age in completed years: age at last birthday, i.e. number of complete years lived by an individual at a given moment in time.
Age reached: difference between the current year and the year of birth. It is used to define a birth cohort
Exact age: it measures the exact period of time elapsed since birth and therefore increases continuously. It is expressed in years, months and days, or in tenths or hundredths of a year.

Person whose declared nationality is different from that of the country where he/she resides.

In France, the term applies to the increase in the birth rate
after 1945 and up to the mid-70's.

All individuals born during a specified period, generally a calendar year.

Methods employed by couples to prevent sexual intercourse from leading to conception and birth.

The term birth control is often used synonymously with such terms as contraception, fertility control, and family planning. But birth control includes abortion to prevent a birth, whereas family planning methods explicitly exclude abortion.

Interval between marriage or sexual union and the first birth (first birth interval), or interval between two successive births in the current union.

Chronological order of live births for a woman or a couple.

The first-order birth refers to the eldest child in a family.
Depending on the statistics available, birth order may refer to all births to a mother or only to the births of the current marriage.

or Optimum population

The maximum sustainable size of a resident population in a given ecosystem. This size varies according to the lifestyle and standard of living of the inhabitants.

Disease or circumstance that has led to death.
Causes of death are known thanks to the information entered by doctors on death certificates, indicating the disease or the circumstances responsible for each death. Cause-of-death statistics are established in each country using an international classification of diseases. This standard classification makes it possible to compare countries and to study changes within the same country.

Cause-specific death rate : The number of deaths attributable to a specific cause per 100,000 population in a given year.

The condition of a person who has never been married, not to be confused with that of a person who does not cohabit with a partner.

An operation to count the population of a country.

A census is the process of counting every member of a population living in a particular territory at a particular time.
All inhabitants fill in a census form and the data is processed to determine the characteristics of the population concerned (sex, age, occupation, housing conditions, place of work or study, etc.). Censuses may be varied in scope (local, national, etc.).

Censuses provide a means to determine the population's needs in terms of community infrastructure: schools, hospitals, public transport etc. They also enumerate the resident population, upon which many legal texts relating to elections and public financing are based.

Most countries conduct a census every five or ten years. In France, the last general population census was in 1999. Since 2004, a new method has been introduced, with a proportion of the population being surveyed on an annual basis.

Citizenship is the status of a legal member of a sovereign state.

System of registration of births, deaths and marriages.

Records of events in an individual's life are known as vital records.
Events which modify an individual's vital records (adoption, name change) are recorded in the register of births, along with events which create obligations with respect to others: marriage, divorce, birth, legitimation or recognition of children.

Civil registration guarantees the recognition of individuals by the state. In France, parish registers have existed since the the ordinance of Villers-Cotterêts in 1539 which obliged priests to keep a register of christenings. In 1792, the registers became municipal. The main purpose of civil registration is to guarantee the rights and duties of individuals, which begin at birth and end at death. Registration of events also provides statistical data for counting births and deaths to monitor natural population change. In some countries, the population registers also include individuals' addresses, making it possible to count migrant flows and determine net migration.

The civil solidarity pact, referred to as the "PACS" is "a
contract concluded between two physical persons who have reached
the age of majority, of different or the same gender, for the
purposes of organizing their life in common". It was enacted by the
law of 15 November 1999. It establishes rights and duties between
the co-signatories in terms of material support, housing,
inheritance, taxation and social welfare. It does not modify the
rules on lawful descent or adoption or on parental authority if one
of the co-signatories is already a parent.

The PACS can be dissolved at the request of one or both signatories
by declaration to the civil court. It is automatically dissolved by
marriage or by the death of one or both signatories.

The situation of people who share the same dwelling.

As a simplification, the term cohabitants is often used to describe couples who live together without being married, and such unions are referred to as consensual unions.

A group of persons who experience the same demographic event (birth, marriage, birth of a first child, etc.) in the same year or period of time.

Cohorts serve as the basis for longitudinal analysis of individuals over time.

All persons born in a particular year are described as a birth cohort. All persons marrying in a particular year are known as a marriage cohort.

A group of persons who experience the same demographic event
(birth, marriage, birth of a first child, etc.) in the same year or
period of time.

The average number of children born to women belonging to the
same cohort once they have reached the end of their reproductive
life (in practice at the age of 50).

It is the sum of the age-specific fertility rates of a
cohort.



Synonym : Lifetime fertility

Long-term cohabitation of an unmarried couple.

A canvass of selected persons or households in a population, usually used to infer demographic characteristics or trends for a larger population segment or for the population as a whole.

Shift in a population from a traditional demographic regime marked by high fertility and mortality to a modern demographic regime in which fertility and mortality are low.

Demography is the scientific study of human populations to determine population size, population composition by sex, age, marital status, etc., and to project future trends. It uses statistical information supplied by censuses and vital records supplemented by surveys.

Ratio of the economically dependent part of the population
(children and persons aged 65 or over) to the working-age
population (aged 15-64).

The result is expressed as the number of persons under 15 and aged
65 or over per 100 persons aged 15-64.



Age boundaries may vary. Youth dependency ratios and old-age
dependency ratios can be calculated separately.

The state of population decline.

The final legal dissolution of a marriage, involving the
separation of husband and wife by judicial decree which confers on
each the right to remarry under the laws of individual
countries.



Total divorce rate

The total divorce rate indicates the number of divorces in a
fictitious cohort of marriages whose divorce rates for each
duration of marriage are the same as those observed in a given
year. It may differ from the final proportion of divorced couples
in a marriage cohort.

The number of years required for a specified population to double in size at the current rate of population growth.

A mass outbreak of a disease in a particular geographic area which spreads and then disappears relatively quickly.

or Health transition

The period of mortality decline which accompanies the demographic transition. It is characterized by improved health, nutrition and organization of health services and a change in the causes of death, with mortality from infectious diseases progressively being replaced by mortality from chronic and degenerative diseases and accidents.

The study of the frequency, distribution, and causation of
disease in a population, based upon the investigation of factors in
the physical and social environment.

An expression used to describe the excess mortality of men compared with that of women.

For a given age or age group it is usually measured as the ratio of the male mortality rate to the female mortality rate

Group of people related by birth, marriage or adoption.

A family is a group of people belonging to a single household.
For the census, a family comprises a maximum of two successive generations: a couple with or without children or a single-parent family.
The extended family also includes uncles and aunts, grandparents, cousins and nephews, and grandchildren.

The methods used by couples to regulate their reproduction.

The effort of couples to regulate the number and spacing of births through artificial and natural methods of contraception. Family planning connotes conception control to avoid pregnancy and abortion, but it also includes efforts of couples to induce pregnancy.

Measures taken by the authorities to limit the cost burden of raising children or to help families in certain situations.

Biological capacity, of a woman, a man or a couple, to produce a live birth.

Fecundity varies widely from one individual and from one couple to another. Beyond such individual variations, fecundity in women reaches its maximum at around age 20, starts decreasing slowly to age 35, and then more rapidly after age 35 until it falls to zero at around age 45 or 50.

The reproductive performance of an individual, a couple, a group, or a population.

The term fertility is used instead of birth rate when births are counted in relation to the number of women of reproductive age. The fertility of a cohort can be summarized by completed fertility and mean age at childbearing, whereas the total fertility rate (TFR) measures the fertility of a given year. When a distinction is made by birth order, the terms first-birth fertility, second-birth fertility etc. are used.

Policy which attempt to act indirectly on fertility rates (either towards an increase, or more often a decrease in developing countries)

Distribution of fertility by mothers' ages
It can be determined by calculating mean age at childbearing, or if it concerns first birth fertility, mean age at first birth.
When a decrease in fertility at younger ages is at least partially offset by an increase in fertility at older ages, fertility timing is said to be postponed.

Transition from a regime of "natural" fertility (not controlled by couples) towards a regime of "controlled" fertility.

Line of kinship uniting a child with its father and its mother.

Mortality of infants who are stillborn or die before the age of
one year. Foeto-infant mortality rate Ratio of the
number of infants who are stillborn or die before the age of one
year to the total number of births (live and stillborn).

Gender is a notion used in the social sciences. It refers to the
cultural dimension of sexual differentiation (such as the
distribution of power or the breakdown of roles between men and
women in a society), while the notion of "sex" reflects a universal
biological reality.

or Epidemiological transition

The period of mortality decline which accompanies the demographic transition. It is characterized by improved health, nutrition and organization of health services and a change in the causes of death, with mortality from infectious diseases progressively being replaced by mortality from chronic and degenerative diseases and accidents.

A set of people indicated as living in the same housing unit, regardless of whether or not they are part of the same family.

A household may be composed of a single person. When several families share the same accommodation the term of composite household is used.
In a census, a distinction is made between so-called "family" households and institutional households which concern people living in group quarters (hospitals, prisons, etc).

The human development index (HDI) is a composite index that measures the development of a country.

The HDI is based on qualitative and quantitative data:
- life expectancy at birth (which gives an idea of the health status of the population);
- the level of education measured by mean years of schooling and adult literacy rate;
- the GDP per capita in purchasing power parity (PPP) US dollars, giving an indication of the mean standard of living in the country.

The HDI is given as a number between 0 and 1. The closer it is to 1, the higher the level of development.

A person who settles in a country other than their country of origin.

In France, a person who has acquired French nationality since arriving in France is still counted as an immigrant, though not a person born as a French national abroad. Immigrants are qualified by their country of origin and not their nationality.

A descendant of immigrant(s) is a person born in France to at least one immigrant parent; this category is also sometimes designated collectively as the « second generation »

Number of new cases of a disease in a year in a given population.

Incidence should be distinguished from prevalence which refers to the number of sick people at a given time.

Incidence rate of a disease
Number of persons contracting a disease per 1,000 population at risk. It is generally expressed for a year.

The mortality of children under the age of one year.

Endogenous mortality refers to deaths attributable to trauma during birth or congenital malformations, while exogenous mortality refers to deaths from external causes (accidents, infectious diseases, etc.)

Infant mortality rate :
Number of deaths of infants under the age of one per 1,000 live births in a given year.

The biological inability of a man, a woman or a couple to produce a live birth.
Synonym: sterility

Proportion of infertile women.

The proportion of women in a cohort who reach the end of their reproductive life without giving birth to a child. Not to be confused with infecundity or sterility, which is the incapacity to conceive.

Migration within a country.

Movement of individuals or populations to settle in a different country.

Migration into a country is referred to as immigration, and migration from a country as emigration. Net migration is the difference between the number of persons who enter a territory (immigrants) and the number who leave (emigrants), generally calculated over a year.

Detailed description of known diseases and injuries.
The International Statistical Classification of Diseases and Related Health Problems (ICD) is published and revised by the World Health Organization and is used world-wide for morbidity and mortality statistics, reimbursement systems and automated decision support in medicine.
Every disease (or group of related diseases) is described with its diagnosis and given a unique code, up to five letters long.

The legal status of a child at birth depends upon the marital status of its mother.

A birth is "legitimate" if the parents are married. A child born outside marriage is "legitimated" when the mother marries.

The act of legitimizing a child born outside marriage.

A child is legitimized when its parents marry or, if marriage is impossible, by a court decision.

In France, a child born outside marriage and not recognized by its biological father may also be legitimized when its mother marries a man who is not the biological father, provided he has recognized the child prior to marriage.
Likewise, a child can be legitimized if its father marries a woman who is not the biological mother, if she has adopted the child before marriage or if the child is under 15.

Deadliness of a disease.

Case Fatality Rate
The proportion of persons contracting a disease who die from it over a specified period. This rate is a measure of the virulence of the disease.

Average number of years a group of individuals can expect to live.

Life expectancy at birth (or at age 0) represents the mean length of life – i.e. the mean age at death – of a synthetic cohort exposed at each age to the mortality patterns of a given year. It is a measure of mortality that is independent of the effects of age structure. Life expectancy at birth is a particular case of life expectancy at age x, which represents the mean number of remaining years of life beyond age x (or mean survival duration at age x), under the mortality conditions of the year in question.

The maximum age that human beings could reach under optimum conditions.
Estimated at 100 years by Buffon at the end of the 18th century, maximum life span has since been extended to 105, 110, 115 years, etc., rising each time the previous limit is exceeded. The record is held by a Frenchwoman, Jeanne Calment, who died in 1997 at the age of 122. Her dates of birth and death are authenticated by the official registers.

A tabular display of life expectancy and the probability of
dying at each age (or age group) for a given population, according
to the age-specific death rates prevailing at that time. The life
table gives an organized, complete picture of a population's
mortality.

Legally defined conjugal status (de jure status): single, married, widowed, divorced. Does not encompass civil partnership or consensual union (de facto status).

Legal conjugal union between a man and a women.
The legality of marriage is established by civil, religious or other means according to the custom and law of each country. It does not include civil partnerships or consensual unions.

Some countries have recently authorized marriage between homosexual couples.

Probability for a person who is still single at a given age of marrying before the next age.

Results are recorded in nuptiality tables.

Deaths of women due to complications of pregnancy or childbirth.

Maternal mortality rate
The number of women who die during pregnancy (whatever the term) or within 42 days of childbirth due to causes linked to pregnancy, labour or aftercare per 1,000 live births in a given year.

The mathematical average age of all the members of a population.
For instance, mean age at childbearing in 2006, mean retirement age etc.

Age that divides the population in two parts of equal size, that is, there are as many persons with ages above the median as there are with ages below the median.

Arithmetic mean of the population on 1 January and the population on 31 December of a year. It is used to calculate annual rates.
Synonym: average population

Movement of individuals who leave their place of birth or of residence to settle elsewhere.

There are two types of migration: international migration (migration between countries) and internal migration (migration within a country).

Measures aimed at controlling (or possibly encouraging) migration between the receiving country and sending countries.

The incidence of disease, injury or disability in a population.

The occurence of deaths in a given population.

Crude mortality rate :
The number of deaths in a specified period (usually one year) divided by the average total population in that period (usually taken as the mid-year population). The rate is normally expressed per 1,000 population.

Standardized mortality rate
Adjusted mortality rate for a given cause of death or country calculated by applying a fixed age structure to the age-specific rates observed each year. This technique eliminates the effects of population age structure so that mortality can be compared over time and space.

A sudden broad Increase in the death rate.

Births as a component of population change.

Natality depends upon the number of women in a population and their fertility.

Birth rate :
The number of live births occurring in a population in a given period (usually a calendar year) in relation to population size, usually expressed per 1,000.

Natural increase is the difference between the
number of live births and deaths, generally calculated over a year.
It is positive when the number of births is higher than the number
of deaths and negative when the number of deaths exceeds the number
of births.

Mortality during the first four weeks of a child's life.

It is qualified as early neo-natal mortality when death occurs during the first week of life, and as late neo-natal mortality when death occurs during the following three weeks.

Neonatal mortality rate
The number of deaths of infants under 28 days of age in a given year per 1,000 live births in that year.

Net migration is the difference between the
number of persons who enter a territory (immigrants) and the number
who leave (emigrants), generally calculated over a year.

The frequency, characteristics, and dissolution of marriages in a population.

Crude marriage rate :
The ratio of the number of marriages during the year to the average population in that year. The value is expressed per 1000 inhabitants. A variety of marriage rates are used to measure nuptiality: first marriage rate, remarriage rate etc.

Distribution of first marriages by age at marriage.
Also called mean age at first marriage.

The maximum sustainable size of a resident population in a given ecosystem.
Synonymous : Carrying capacity

The situation where an area's population exceeds the area's carrying capacity.

An epidemic that spreads over a very wide area

Mortality of stillborn infants and infants who die within 7 days of birth.

Perinatal mortality rate
The number of foetal deaths after 28 weeks of pregnancy (late foetal deaths) plus the number of deaths of infants under 7 days old per 1,000 live births and stillbirths.

In demography, permanent celibacy is measured by the proportion of persons who have never been married at the age of 50.

A marriage in which a person of one sex has more than one spouse of the opposite sex.
Polyandry occurs when a woman has more than one husband, and polygyny when a man has several wives. Polygamy contrasts with monogamy. When a person has two spouses the term bigamy is used.

Increase in the proportion of adults and elderly people in a population, due to a decrease in fertility and in mortality.

Population ageing may be due to an increase in the number of old people (top-down ageing) thanks to lower mortality and longer life expectancy, but may also be caused by a deficit of young people (bottom-up ageing), due to declining fertility. In this case, ageing may occur even if the number of old people does not increase.

Population ageing is the consequence of the demographic transition. Until now, it has mainly concerned the Northern countries, where fertility and mortality have fallen sharply, though it is now starting to have an impact in the South. It is likely to be one of the major social changes affecting humanity in the 21st century.

The number of people per unit area, generally expressed per square kilometre.

Expression used to describe the worldwide trend of rapid population growth in the 20th century.

This explosion is the result of a world birth rate which is much higher than the world death rate.

A population increase over a given period.

It represents the sum of natural increase and of net migration, generally expressed for a year. The size of a population increases when there are more births than deaths (natural increase) and more immigrants than emigrants (net migration). The annual growth rate is the ratio of the variation in population size over the year to its size in the middle of the year.

All of the measures explicitly or implicitly taken by the authorities aimed at influencing population size, growth, distribution, or composition.

A population policy is a set of measures taken by a State to modify the way its population is changing, either by promoting large families or immigration to increase its size, or by encouraging limitation of births to decrease it. A population policy may also aim to modify the distribution of the population over the country by encouraging migration or by displacing populations.

Future population assessed as a function of hypotheses on variations in fertility, mortality, and migration.
Demographers often issue low, medium, and high projections of the same population, based on different assumptions of how these rates will change in the future.

Bar graph showing the age-sex structure of a population.
It consists of two sets of horizontal bar graphs (one for each sex, with males on the left and females on the right), with the numbers of persons in each age group along the horizontal axis, and ages along the vertical axis.

The first population pyramid was published in 1874 in a statistical atlas of the United States. For a population with high birth and death rates, it is wide at the bottom (young ages) and narrow at the top (old ages), hence the term pyramid. Its shape varies however.

The population pyramid gives an immediate picture of the demographic regime and the history of a country over a long period. When fertility declines and life expectancy increases, as is the case during the demographic transition, the population pyramid changes shape to resemble a cylinder, or even a spinning top if fertility falls below replacement level. Annual fluctuations in birth and death rates are visible in the pyramid, leaving a durable imprint of the crises experienced by a country, such as famine or war, or of temporary surges in the birth rate, such as the baby boom.

A government data collection system in which the demographic and
socioeconomic characteristics of all or part of the population are
continuously recorded

The distribution of people in a population according to designated demographic traits (e.g. age, sex, country of birth, marital status).

Deaths of infants aged 28 days to 1 year.

Post-neonatal mortality rate
Number of deaths of infants aged 28 days to 1 year per 1,000 live births in a given year.

The total number of people affected by a disease in a population, including both new and existing cases.

Prevalence Rate
Number of people having a particular disease at a given point in time per 1,000 population at risk.

Prevalence data hence show the magnitude of a given health problem and are important in planning services and allocating resources.

Probability of an event occurring between two ages (or durations) among people who have not previously experienced it.

Probability that a person of age x will die before reaching the age of x+n.

It is calculated by dividing the number of deaths at age x by the number survivors at age x. Results are recorded in life tables.

The ratio of events having occurred in a population during a
year to the number of persons in a population in the middle of the
year. When the events are observed over a period shorter or longer
than a year, their number is multiplied or divided by the
appropriate factor so as to preserve the rate's annual dimension. A
rate may refer to all of the population (crude rate), or to an age
or age group (specific rate) For certain phenomena, the rates are
computed according to the period of time since the origin event:
this is the case for duration-specific divorce rates. In this case,
since the number of surviving marriages is unknown, the rate is
calculated by determining the ratio of the number of divorces to
the size of the initial marriage cohort.

The act of declaring oneself to be the father or mother of a child born outside marriage.

A child born outside marriage may be recognized before, after or at the time of birth.
A child may be recognized jointly by both parents, by the father alone or the mother alone. The same child may be recognized several times in succession.
When a child is recognized before or at the time of birth, this recognition is indicated on the birth certificate.

Family composed of an adult couple, married or unmarried, living with at least one child born from a previous union of one of the partners.

Replacement of the generations of childbearing age by the generations being born.

The replacement of a generation of mothers is measured by comparing the number of women in a generation with the number of their daughters. Replacement is guaranteed if there are as many daughters as there are mothers.
Because of the sex ratio at birth (105 boys for 100 girls) and low infant mortality, replacement level fertility occurs in developed countries when mothers have around 2.1 children.

The indicator that measures in which conditions generations are replaced.

It is computed by establishing a ratio between the number of daughters and that of their mothers, independently from effects due to population structure. This calculation can be made by taking into account the mortality (net reproduction rate) or in the absence of mortality (crude reproduction rate). In practice this rate is usually computed for a given year or period, in that case it measures the conditions of the moment in terms of reproduction.

Ratio between the number of males and the number of females, expressed as the number of males per 100 females.

At birth, the sex ratio is 105 boys for 100 girls. Since male mortality is generally higher than female mortality, the sex ratio decreases with age, and the proportion of women overtakes that of men. In France, there are more women than men from age 35 (in 2005) and eight in every ten centenarians are women.

Family composed of a lone parent living with at least one child.

A population with an invariable age structure and a fixed rate of natural increase.

Any closed population without any migratory exchanges with the outside world, subjected to invariable fertility and mortality conditions over a long period tends towards a stable condition with an invariable age structure and rate of growth. A stationary population with a zero growth rate is a special example of this.

The standardized mortality rate (SMR) is the ratio of the number
of deaths observed in a population over a given period to the
number that would be expected over the same period if the study
population had the same age-specific rates as the standard
population. If the rate is greater than one, it is interpreted as
excess mortality in the study population.

It is a special case of a stable population.

Inability of a man or woman to produce a live birth.

Sterility may be the result of a physiological incapacity (infecundity) or voluntary sterilization.

Expulsion from the mother of a dead foetus after 24 weeks of gestation.
Synonym: late foetal death

The expulsion or extraction of an embryo or fœtus from the mother's body before the 6th month of pregnancy is called an abortion or a miscarriage

Stillbirth rate:
The stillbirth rate is the ratio of stillbirths to total live and stillbirths.

The total fertility rate (TFR) can be interpreted as the number of children a woman would have during her lifetime if she were to experience the fertility rates of the period at each age. Though the TFR and completed fertility are often at similar levels, the two indicators may diverge when fertility timing is modified. Postponement of births brings down the total fertility rate, even if completed fertility remains unchanged.

The sum of the age-specific fertility rates for a particular period (usually a year).

The total first marriage rate is the sum of age-specific first
marriage rates. It may be quite different from the final proportion
of persons who marry at least once in a birth cohort (the
complement of permanent celibacy).

Growth in the proportion of a population living in urban areas.

Death caused by accidental injury or poisoning, by suicide or homicide

The world population comprises 6.5 billion living human beings
(in 2005) and it is increasing steadily. Its size and its
characteristics – natality, mortality, age-sex structure – are
determined by collating the information supplied by the population
censuses of the different countries of the world.