glossary    * A *
Demographical and statistical terms Symbols
abortion
is defined, with reference to the woman, as any interruption of pregnancy before 28 weeeks of gestation with a dead foetus. There are two major categories of abortion: spontaneous and induced. Induced abortions are those initiated by deliberate action undertaken with the intention of terminating pregnancy; all other abortions are considered as spontaneous.
 
abortion rate
is a measure of the frequency of abortion in a population during a given period, usually a year. Abortions may be related to the total population or to the number of women in the reproductive ages, and may be specific for age, parity or any other characteristic.
 
abridged lifetable
is one in which most functions are given only for certain pivotal ages, frequently spaced at five or ten-year intervals after infancy. It is a life table computed by age intervals of 5 or 10 years, instead of single years of age. The youngest intervals are usually specified as age> 0-1, 1-4. The oldest age interval is an open interval.
 
absolute average difference
estimates the degree of fitting between observed and theoretical data.
ISC
abstinence
abstinence from coitus, particularly periodic abstinence is often included among contraceptive or birth control method.
 
adjusted rates
rates which have been standardized for age and/or other compositional characteristics in order to make them comparable with each other.
 
age and duration-specific divorce rates
are given by the number of divorces of women (or men) aged x to x+n and married t to t+k years, divided by the persons years lived by the corresponding married population.
 
age-child ratio
defined as the ratio of the elderly (age 65 and older) to the population in younger ages (under age 15).
IV or ACR
age dependency ratio is the ratio of the young and the elderly to the adult population. ID
age distribution of a population
when the distribution of a population is given by individual years of age.
 
age groups
represents the age distribution of a population, which may be five-year age groups, also called quinquennial age groups or broad age groups,such as 0-19 years, 20-59 years, 60 years and over.
 
age of maximum value of fertility rates
age corresponding to the maximum value of a given age-specific fertility rates distribution.
FXM
age heaping
tendency of some people to round their ages to numbers ending in zero or five or to report certain ages instead of others. Also known as "age preference " or "digit preference".
 
age of maximum value of the resistance function
age corresponding to the maximum value of resistance function.
XM
age-pattern of fertility
relative (proportionate) distribution of a set of age-specific fertility rates. It espressed the relative contribution of each age group to total fertility.
 
age-sex structure of a population
the number or proportion of the total population which falls in each category of a cross-classification by sex and age (either single years or age groupings).
 
age-specific death (mortality rate), see Central death rate.
 
age-specific divorce rate
is given by the number of divorces of women (or men) aged x to x+n divided by the number of the person years lived by married women (or men) between ages x and x+n. The denominator may be also represented by the total number of the person years lived at age x to x+n by women or men.
 
age-specific fertility rate
rate calculated by relating births generated during a give period from a number of women of age x (or of age x,x+h) to the quantity of women living of age x (or in age x, x+h).
f(x) or F(x)
age-specific first marriage rate
is given by the number of first marriages of women (or men) aged x to x+n in a given year divided by the person years of women (or men) aged x to x+n who are exposed to the "risk" of first marriage.
As second kind, the denominator may be represented by the total number of person years lived by men or women aged x to x+n.
 
age-specific first net migration rate
is computed as the amount of net migration (difference between immigration and emigration) at a given age per 1000 of the midyear population at this age.
 
age-specific first net migration rate
is computed as the amount of net migration (difference between immigration and emigration) at a given age per 1000 of the midyear population at this age.
 
age-specific probability of emigration
the annual age-specific probability of emigration between exat age x and x+1 is computed as the number of emigrants at a given age during the year related to midyear population at age x, plus half of the deaths during the year at age x.
 
age-specific remarriage rate
is given by the total number of remarriages for persons aged x to x+n, divided by the total number of person years lived by divorced, plus the number of the widowed between age x to x+n.
 
age standardization
a procedure of adjustment of crude rates ( birth, death or other rates) designed to reduce the effect of differences in age structure when comparing rates.
 
average annual rate of change
the average per cent increase or decrease per annum required to account for observed numerical change in size between two dates.
 
average family size
is the number of children for couple.
 
average parity
is the mean number of children even born per woman.
 

back arrow  glossary main page