What would be the proper source format for an age (year, month, day) calculated by me?

Question

Details:

I want to calculate and add to a profile the age in years, months and days.

What would be the proper source format for this self generated fact?

Comments

Just a side note:  there was a period of time in the late 1800s and early 1900s (at least in eastern U.S.) where the custom was to engrave the date of death and the life span on a tombstone, but not the date of birth.  I have seen some one-day discrepancies in (calculated) birth dates across several records that appear to result from this practice.  I think the issue derives from whether you count both the day of birth and the day of death as part of the life span or whether you just do the subtraction.  So if you proceed with this, I would recommend specifically stating how you did the calculation.

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Good point to know. Also, I would explain such a discrepancy  as this under “Research Notes”.

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Why is it necessary to cite the calculation? To do the calculation, you need both birth and death date dates, you should have sources for both of these.

This is no different from getting a birth year from a census record. You cite the census record that states the age.

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Dennis, couldn't leap years sometimes also affect the calculations?

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I suppose it could if your count of days includes a Feb 29 in the year of birth or death.  In the customary calculations I've seen though, a year is counted as a year and a month as a month regardless of how many days were in it.

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Yes, that is what I meant.  When you count the number of days, if they represent a fraction of a month, then you need to know the number of days in the first of the two months.

Edit:  What I meant by "fraction of a month" was a fraction of a month that overlapped a month-end.

Answer 1

I'd say "WikiTree contributors" are the default source wherever no other authority is cited, and this doesn't need to be stated.

You can't cite yourself as a better authority, unless you're citing something you've previously published.

Comments

I think the specific question referred not to facts presented by Tommy, but to a calculation performed by him, i.e. you already have a good source for the actual full birth date and the actual full death date, and you wish to write in the narrative the number of years, months and days that the person lived.  If you present that, and the dates themselves are already cited, I don't think you MUST cite the source of the calculation itself, but I think you can, and that is the way I would cite it.

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If I see an age in years, months and days, I would want to know where it came from, i.e. headstone, obituary, death certificate, some other person’s info, or my own. Also, I think what dates were used in the calculation and the source of the dates that were used should be stated too.  I have come across calculated ages in years, months, days that are simply incorrect and they need to be pointed out and documented with a correct calculation. I would put this under a “Research Notes” section.

Answer 2

I've not done this, but if I did, I might add an inline citation as follows: <ref> Calculated by [[Day-1904|Jack Day]] from dates on the gravestone. </ref>

Answer 3

There can be ambiguity in the value you get, depending on how you do the computation:

https://www.wikitree.com/g2g/818211/convention-for-writing-birth-date-inferred-from-exact-death

(It's more than just whether they included the birth date and/or death date or not -- it's an issue of the order of operations when doing a compound subtraction. And there’s a huge issue if there is a calendar change, since for instance the British Empire cut 11 days out of the year in 1752.)

So I think it best to record the range of possible values resulting from such a computation or else explain carefully how you did it. Unfortunately, I don’t think there’s jargon you could use as a substitute for this explanation. But if you will be doing this many times, you could setup a freespace page to explain the computation.

Answer 4

I agree with George and RJ.  If your calculation is based on birth and death dates, then those are the facts that need to be sourced.  Any reader can then recalculate the life span, should they care to.

Comments

And when the reader does this, and it doesn’t match the age on the headstone, the death certificate or an obituary or a combination of them, then what?

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That is not an issue unique to this discussion, and I don't see how a contributor stating that he made the calculation would clarify anything.

When I find a headstone and death certificate or obituary, etc., in conflict I make my best judgment of which is most accurate and explain that in the narrative, or in a footnote or research note (depending on the complexity).

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Okay, let's say that someone (maybe you) does an age calculation and you do it incorrectly, but you don't state that you did the calculation.  And some one else comes along and sees that age calculation and decides to verity it and it is off by three days, then that leaves that person wondering why it is wrong and where did the original age come from.  But if I know that someone calculated it themself, and that it wasn't added from some other source document, then I would be more likely to believe the person calculating it did it wrong.

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If the calculation comes from a source, you can cite the source.  But it it's wrong by three days, it's still going to be wrong by three days.  

How often is three days going to be critical?