lt.representativity: Checks the representativity of the non-adult age groups in a mortAAR
life table
Description
Weiss 1973, 46f. and Bocquet-Appel and Masset 1977 (see also
Herrmann et al. 1990, 306f.) have devised indices which check
if the non-adult age groups are represented in proportions as can be
expected from modern comparable data. Whether this is really applicable
to archaeological data-sets is a matter of debate.
Usage
lt.representativity(life_table)
Value
data.frame showing the indices and explaining their interpretation.
Arguments
life_table
an object of class mortaar_life_table.
Details
Weiss chose the mortality (qx) as deciding factor and claimed that
(1) the probability of death of the age group 10--15 (5q10)
should be lower than that of the group 15--20 (5q15) and that (2)
the latter in turn should be lower than that of age group 0--5
(5q0).
In contrast, Bocquet-Appel and Masset took the raw number of dead (Dx)
and asserted that (1) the ratio of those having died between 5 and 10
(5D5) to those having died between 10 and 15 (5D15) should be equal or
larger than 2 and that (2) the ratio of those having died between 5 and 15
(10D5) and all adults (>= 20) should be 0.1 or larger.
Due to the specific nature of the indices, they only give meaningful
results if 5-year-age categories have been chosen for the non-adults.