Are Ducklow Descendants Living Longer Over Time?

The short answer: “Yes.”

[Published April 15, 2010]

Having birth and death dates for many of our common ancestors, I became interested in seeing if, through time, the Greater Ducklow family was living longer.  The answer is “Yes.”   From births of descendants born in the 1840s to those born in 1920s the average age of death rose significantly – from age 51 to age 71. 

Of this 20-year gain in lifespan, most of the increase came in the period of the 1860s to 1880s and was primarily due to fewer infant deaths.  The sharp increase then leveled to an average death at age 66 - 67 in the 1880s through the 1910s.  Longer average life spans of those born in the 1910s would have likely continued to increase beyond age 67 but several men’s lives were cut short when killed while serving in the military [WWII].  Descendants born in the 1920s did live longer, with an average death age of 71 [see footnote 1].  There is not enough death dates to analyze average lifespan for those born after 1929.  Here is the data:

Birth Period    # of Births   % Yet Living   Avg. Death Age   Death Age Range

1840s-1850s          11                  0%                          51                       1-90

1860s-1870s          10                  0%                          66                       7-87

1880s-1890s          21                  0%                          67                       0-93

1900s-1910s          41                  3%                          67*                     0-98

1920s                      40                 25%                         71*                     15-85

What was initially surprising is how low the average death age is.  Examining the data in detail shows that the infant and youth mortality rate had big impact on the averages.  Of the 113 known births and deaths for this study, there were six deaths of children between the ages of 0 and 2.  There were five deaths of children between the ages of 3 and 19 and there where three deaths of young adults between the ages of 20 and 25.

So this leads to the question: “Of the Ducklow descendants that lived to be over 25 years old, what is the average age of death?” Here is the data:

Birth Period    # of Births   % Yet Living   Avg. Death Age   Death Age Range

1840s-1850s           8                 0%                         69                         36-90

1860s-1870s           9                 0%                         73                         52-87

1880s-1890s         18                 0%                         77                         46-93

1900s-1910s         35                 3%                         76*                       49-98

1920s                     39                25%                        72*                       36-85

Those descendants born in the 1840s-1850s who survived there childhood and early adulthood went on to live to an average age of 69, a gain of 18 years of life!  Surviving these early years also added to the average age of death in the other time periods too, but not as dramatically.

OK, so what happens if you look at all the Ducklow descendants in the study group that lived to at least age 50?  How much of an increase in the average life span occur if you live at least that long?  The answer: On average, the death age occurs in the mid- to late-seventies.  This lifespan occurs consistently for all time periods the descendant was born. Here is the data:

Birth Period    # of Births   % Yet Living   Avg. Death Age   Death Age Range

1840s-1850s           6                 0%                           79                        58-90

1860s-1870s           9                 0%                           73                        52-87

1880s-1890s          17                0%                           79                        57-93

1900s-1910s          35                3%                           78*                      51-98

1920s                      33               25%                          77*                      56-85

Interestingly, no one in the greater Ducklow family born between 1840 and 1929 has lived to be over 98 years.  It seems likely that this statistic will not hold to be true for those born after the 1920s.

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Footnote 1: Study based on 113 known birth and death dates of the greater Ducklow family born between 1840 and 1929. 

 Footnote 2: Because the early data has so few ancestors, the data was grouped into 20-year time periods [expect the 1920s] in an attempt make the data more statistically valid.

 * Footnote 3:  There is one descendant born in the 1910s who is living.  The average age of death in this period could increase slightly upon her death.  There are ten descendants born in the 1920s who are living (out of a group of 40).  The average age of death for this time period will continue rise until all have passed.

 Footnote 4: While there is data on births and deaths for time periods beyond the 1920s, there is not enough data to perform meaningful analysis.

 Footnote 5: Our common ancestral grandparents, Thomas and Elizabeth Ducklow, were not included in the study as they were born in 1812 and 1822 respectively.  The data in the study is their descendants.  Thomas died at age 79 and Elizabeth died at age 81.  

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