Infantile Mortality Rates.

The simplest measure of the mortality experienced by children during the first year of life, for any one calendar year, is obtained by calculating the ratio of the number of infantile deaths in that calendar year to the number of births in the same calendar year. This ratio is called a crude death rate and is published annually for Australia by the Commonwealth Statistician index of infantile mortality. An alternative method for calculation of this index has been put forward by V. G. Valaoras in a paper in Population Studies, December 1950. Dr Valaoras properly points out that the simple method described above is defective, mainly because it fails to refer the infant deaths to the appropriate group of births from which the deaths arose. The first defect is not important when births are being maintained at a fairly constant level. It is, in such circumstances, not unreasonable to assume that births are evenly distributed throughout each calendar year. Recently, however, birth rates have been subject to severe variations and the distribution of births during each calendar year has been very uneven.