Billeter J

Billeter J is a measure introduced in 1954 by the Swiss statistics professor Ernst Peter Billeter for the comparative description of demographic aging.

definition

Billeter suggests representing the age structure of a population using the measure J.

${\ displaystyle J = {\ frac {P_ {0-14} -P_ {50 +}} {P_ {15-49}}}}$

P _0-14 : Population aged _0-14 years inclusive

P _15-49 : population aged 15 to 49 years inclusive

P ₅₀₊ : population aged 50 and over

Both absolute population figures and population proportions can be used to calculate J.

J von Billeter is the quotient of the difference between the still reproducing part of the population (P _0-14 ) minus the no longer reproducing part of the population (P ₅₀₊ ) divided by the reproductive part of the population (P _15-49 ). If the part that is no longer reproducing exceeds the part that is still reproducing, the quotient becomes negative (less than zero). This is to show the status of a population in terms of its demographic development potential.

Range of values

The value of J can assume very different values, depending on the age structure of a population.

Positive values from J

J assumes positive values if the proportion of young people in a population is greater than the proportion of those over 50. For example, the majority of countries in Africa and Asia have high values, because here, with a high birth rate and low life expectancy, the number of children and young people clearly exceeds the number of old people.
According to Billeter, such societies have a high degree of demographic development potential and are therefore rapidly growing populations.

J equals 0

This occurs when the number of people under 15 corresponds to the number of people over 50. Such a relationship was observed in Europe around the end of the 1950s .

Negative values of J

J assumes negative values if the proportion of over 50-year-olds in a population is greater than the proportion of children. In the western industrialized countries the values of J are well below 0. Here the birth rates are below the reproductive level . At the same time, rising life expectancies mean that societies are aging.
In relation to the possibility of demographic development, these are shrinking populations.

Individual evidence

↑ Axel Priebs: Wehrhahn, Rainer; Sandner Le Gall, Verena (2011): Population geography . In: spatial research and spatial planning . tape 70 , no. 2 , March 16, 2012, ISSN 0034-0111 , p. 163–164 , doi : 10.1007 / s13147-012-0149-z ( springer.com [accessed October 10, 2018]).

[1] Axel Priebs: Wehrhahn, Rainer; Sandner Le Gall, Verena (2011): Population geography . In: spatial research and spatial planning . tape 70 , no. 2 , March 16, 2012, ISSN 0034-0111 , p. 163–164 , doi : 10.1007 / s13147-012-0149-z ( springer.com [accessed October 10, 2018]).