Wednesday, June 19, 2013

Lifespan Statistics Revisited, Again

Using my genealogy software, I first generated a lifespan report from six different family databases back in 2008 - Age is Relative, There is a lot of different data contained in the report, as can be seen in the original post, however for this post I am going to focus on average lifespan.

2008 Statistics

Note: The numbers of individuals given are for the entire database, and includes those for whom both birth and death aren't known. The average lifespans are calculated on a smaller number of individuals.
Full Database
695 males: Avg lifespan: 61
603 females: Avg lifespan: 62

"Direct Ancestors" Only
71 males: Avg lifespan: 67
58 females: Avg lifespan: 68

Descendants of Israel David Neimark  (died approx 1890)
55 males: Avg lifespan: 66
53 females: Avg lifespan: 74

Descendants of Me’er Kruvant (born before 1795)
116 males: Avg lifespan: 68
110 females: Avg lifespan: 70

Descendants of William Denyer (1794-1848)
121 males: Avg lifespan: 53
103 females: Avg lifespan: 61

Descendants of Andrew Van Every (1798-1873)
93 males: Avg lifespan: 49
82 females: Avg lifespan: 48
For each of the last four databases, the forebear is a 3rd great grandfather, so they are roughly equivalent in generation. I wondered at the causes of the apparent lower lifespans for my Denyer and Van Every lines. One possible cause included rural vs urban living. Another possible cause included sampling size. Did I just not have enough data? Perhaps, over time, as the database grew, the average lifespans for the different family branches would even out.

2009 Statistics

In 2009, my database had grown, so I generated some updated statistics in Database Size and Lifespan Revisited for the full database, and for one family in particular.
Full Database
1030 males: Avg lifespan: 60
921 females: Avg lifespan: 62

Kruvant Descendants (Me'er and his two brothers)
368 males: Avg lifespan: 58
367 females: Avg lifespan: 62
I discussed the dramatic drop in lifespan for the Kruvant family. It wasn't unsuspected, as I had just entered a large Register I had received from a cousin researcher including many Lithuanian cousins who 'died' in rather graphic ways between 1939-1942. Though one might point out that while the lifespan for that family dropped significantly, the result was pretty close to the full database. Was this really due entirely to the Holocaust, or did the simple growth of data play a role?

Current Statistics

I didn't consider this possibility back in 2009, but as my database has grown even more since then, I thought I would return to this topic, and I realized I needed to address it.

The only way to do that was to generate a separate Kruvant database, run the statistics report, remove from that database every victim of the Holocaust, and then run the statistics report again. While I was just deleting records, and in a database I had generated only for this purpose, the process was a little disturbing, as I clicked on names, and the software asked if I was sure I wanted to delete the individuals.
Full Kruvant Line
380 males: Avg lifespan: 58
374 females: Avg lifespan: 63

Edited Kruvant Line
355 males: Avg lifespan: 63
351 females: Avg lifespan: 69
It appears the Holocaust accounted for almost all of the drop in the lifespan for Kruvant females, but it was only part of the equation for the males.

Below are the current results for several other databases.
Full Database:
1471 males: Avg lifespan: 61
1341 females: Avg lifespan: 63

79 males: Avg lifespan: 67
78 female: Avg lifespan: 67

Deutsch Line:
95 males: Avg lifespan: 66
80 females: Avg lifespan: 75

Denyer Line:
188 males: Avg lifespan: 57
180 females: Avg lifespan: 62

Van Every Line:
158 males: Avg lifespan: 53
134 females: Avg lifespan: 53

Newmark Line
114 males: Avg lifespan: 69
129 female: Avg lifespan: 73

Dudelczak Line
152 males: Avg lifespan: 63
146 females: Avg lifespan: 73
The average male lifespan for the Denyer descendants has improved with added data, whereas the average female lifespan hasn't by much. The averages for my Van Every line have also improved, but only slightly. While the data so far is sparse, my mother's paternal Deutsch family appears to be among the longer-lived in my tree.

Some people might wonder at why my full database hasn't grown more in six years of research.  My database could be huge, especially on my maternal line, if I added everything I found from Ancestry's Public Trees, WorldConnect, etc. Early on in my research I found at WorldConnect a 6795 individual database containing every individual from the genealogy: A Genealogical Record of the Descendants of Henry Rosenberger of Franconia, Montgomery Co., Pa, Rev. A.J. Fretz, 1906. I downloaded the database, but I didn't merge it with my own. (Even if I trust Fretz's research, I have no way to know if the person who entered the data copied the data correctly from the book.) It would certainly have impacted my statistics greatly if I had:

Rosenberger Descent
3435 male: Avg lifespan: 33
3360 female: Avg lifespan: 32

I believe the low figures are due mostly to a very high infant mortality rate.

For some perspective I looked at two more databases.

First, I looked at my wife's database. I've only begun researching, and haven't entered all the data from a Register someone else produced. However, so far, it seems the women have a significantly higher lifespan than the men in her family.

Jen’s family
175 males: Avg lifespan: 59
165 females: Avg lifespan: 67

For another perspective, I looked at the Royal database provided with my genealogical software program, iFamily. The data goes back to the middle ages on some lines, so one would expect a lower average lifespan, which is the case.

Royal Database
1686 males: Avg lifespan: 49
1322 females: Avg lifespan: 52

In summary

Regardless of the reasons, whether they may be based on geography, time, genetics, or something else, different families have different average lifespans. The women in my separate family databases seem to have longer lifespans, which is what I have been told is the case in general. However, in my full database, the gender difference is much less. This makes me wonder if there are some branches of my family where the stats are reversed.

Size (M/F)
Lifespan (M/F)
Van Every
Jen’s Family

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