I think I have a possible explanation. I have been working with a recent family file where I still have lots of missing data. On a quick estimate only about 20% of my individuals have both birth and death data and the numbers for century-lifespans are about 20% of the gender-lifespans which suggests that the factor used to calculate the average might be the total number born in the century rather than the total number who have a calculated lifespan.
So I opened a file that I haven't worked on for a while where I have about 50% with both birth and death data and found that the century-lifespans are now about 50% of the gender lifespans. On this rather thin basis of two files I think that the century-lifespan statistics have been averaged over the wrong population. David On 16/12/2013 19:32, David Newton wrote: > Some good points here. As it happens I have no individuals of > indeterminate sex but I do have a significant number with missing birth > or death dates which makes the population available for the lifespan > statistics small. However, I still cannot see any reason why there > should be such a big discrepancy in gender related lifespans and century > related lifespans. > > David > > On 16/12/2013 18:41, Kurt Kneeland wrote: >> Can't tell you specifically, but it sounds like you have a relatively >> high proportion of infant deaths with no sex specified. So you get a >> bunch of zeros included in the overall average that are not included >> in the male/female averages. >> >> I don't think an individual is included in the averages at all if >> either the birth date or the death date is missing. However, a >> christening date might be used in place of a missing birth date, and a >> burial date might be used in place of a missing death date. >> >> -----Original Message----- >> From: David Newton [mailto:[email protected]] >> Sent: Monday, December 16, 2013 6:05 AM >> To: [email protected] >> Subject: [LegacyUG] Lifespan, and other, statistics >> >> Could one of you explain to me how the statistics are calculated? >> >> In my family file the average lifespan by century never exceeds 17 >> years whereas the average male and female lifespans are around 53 and >> 48 respectively. These figures seem to be inconsistent with each other >> but in the absence of how the calculations are done I cannot be sure >> what it is telling me. >> >> David >> >> >> >> Legacy User Group guidelines: >> http://www.LegacyFamilyTree.com/Etiquette.asp >> Archived messages after Nov. 21 2009: >> http://www.mail-archive.com/[email protected]/ >> Archived messages from old mail server - before Nov. 21 2009: >> http://www.mail-archive.com/[email protected]/ >> Online technical support: http://www.LegacyFamilyTree.com/Help.asp >> Follow Legacy on Facebook (http://www.facebook.com/LegacyFamilyTree) >> and on our blog (http://news.LegacyFamilyTree.com). >> To unsubscribe: http://www.LegacyFamilyTree.com/LegacyLists.asp >> >> >> >> >> >> Legacy User Group guidelines: >> http://www.LegacyFamilyTree.com/Etiquette.asp >> Archived messages after Nov. 21 2009: >> http://www.mail-archive.com/[email protected]/ >> Archived messages from old mail server - before Nov. 21 2009: >> http://www.mail-archive.com/[email protected]/ >> Online technical support: http://www.LegacyFamilyTree.com/Help.asp >> Follow Legacy on Facebook (http://www.facebook.com/LegacyFamilyTree) >> and on our blog (http://news.LegacyFamilyTree.com). >> To unsubscribe: http://www.LegacyFamilyTree.com/LegacyLists.asp >> >> >> Legacy User Group guidelines: http://www.LegacyFamilyTree.com/Etiquette.asp Archived messages after Nov. 21 2009: http://www.mail-archive.com/[email protected]/ Archived messages from old mail server - before Nov. 21 2009: http://www.mail-archive.com/[email protected]/ Online technical support: http://www.LegacyFamilyTree.com/Help.asp Follow Legacy on Facebook (http://www.facebook.com/LegacyFamilyTree) and on our blog (http://news.LegacyFamilyTree.com). To unsubscribe: http://www.LegacyFamilyTree.com/LegacyLists.asp
