glossary    * B *
Demographical and statistical terms Symbols
balancing equation
addition of the net balance of the components of change (births, deaths and migration) between two dates to the total population at the earlier date in order to  estimate  the population count as of the later date. This may be compared with a population count for the later date.


basal body temperature method
refers to the contraceptive metod in which the woman keeps track of her temperature to identify the safe fecond period


birth at term
birth which is non premature.


birth cohort
a sub-population born in a particular year or set of years, the members of which therefore are of the same age range and pass through life together. Their progress may be charted by following them at successively older ages in consecutive censuses or enumerations.


birth intervals
time elapsed (months) between successive live births, or the intervals between marriage and the first birth, between the first and the second bitrh; and so on.


birth order
the ordinal number of a given live birth in relation to all previous live birth in relation to all previuos live births of the same woman.


birth probabilities
the annual probability that a woman will have a live birth within a specified year of age


birth rate b(t)
rate calculated by relating the number of live births observed in a population during a given period to the size of the population during the period. This rate is usually stated per 1,000, and the most usual period is one year.


birth spacing
is commonly used to refer to the deliberate efforts of couples to pospone a birth.


birth timing
is the interval between marriage and the first birth, and intervals between successive births.


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