the average life expectancy in the roman empire before infant mortality is factored out was 25.
what was the average life expectancy in the roman empire before infant mortality is factored out?
25
when the high infant mortality rate is factored in (life expectancy at birth) inhabitants of the roman empire had a life expectancy at birth of about 25 years. however, when infant mortality is factored out, life expectancy is doubled to the late-50s. if a roman survived infancy to their mid-teens, they could, on average, expect near six decades of life, although of course many lived much longer or shorter lives for varied reasons. although this figure relies more on conjecture than ancient evidence, which is sparse and of dubious quality, it is a point of general consensus among historians of the period. it originates in cross-country comparison: given the known social and economic conditions of the roman empire, we should expect a life expectancy near the lower bound of known pre-modern populations. roman demography bears comparison to available data for india and rural china in the early 20th century, where life expectancies at birth were also in the low 20s.
demography of the roman empire
national leb figures reported by statistical national agencies and international organizations are indeed estimates of "period" leb. in the bronze age and the iron age, leb was 26 years; the 2010 world leb was 67.2 years. for recent years, leb in eswatini (swaziland) is about 49, while leb in japan is about 83. the combination of high infant mortality and deaths in young adulthood from accidents, epidemics, plagues, wars, and childbirth, particularly before modern medicine was widely available, significantly lowers leb. for example, a society with a leb of 40 may have few people dying at precisely 40: most will die before 30 or after 55. in populations with high infant mortality rates, leb is highly sensitive to the rate of death in the first few years of life. because of this sensitivity to infant mortality, leb can be subjected to gross misinterpretation, leading one to believe that a population with a low leb will necessarily have a small proportion of older people. another measure, such as life expectancy at age 5 (e), can be used to exclude the effect of infant mortality to provide a simple measure of overall mortality rates other than in early childhood; in the hypothetical population above, life expectancy at 5 would be another 65. aggregate population measures, such as the proportion of the population in various age groups, should also be used along individual-based measures like formal life expectancy when analyzing population structure and dynamics. however, pre-modern societies still had universally higher mortality rates and universally lower life expectancies at every age for both genders, and this example was relatively rare. in societies with life expectancies of 30, for instance, a 40 year remaining timespan at age 5 may not be uncommon, but a 60 year one was.
life expectancy