How many times removed?

ChrisBowyer · Post by **ChrisBowyer** » 21 Oct 2009 06:42

Corresponding recently with someone who is (according to the How Related tool) my 3rd cousin twice removed, and I his (pressing Swap makes no difference to the result)...

But there's a chart on Genes Reunited apparently reproduced from Tracing Your Family History by Anthony Adolph (Collins, revised edition, 2008), which says that if he is my third cousin twice removed, then I am his first cousin twice removed, or his fifth cousin twice removed, depending on whether he's my grandfather's third cousin or I his (I hope you're following this so far).

The point is surely, regardless of who's 'correct', there are clearly at least two schools of thought, hence some ambiguity with this notation.

I would much prefer FH to use the notation found in Tribal Pages, which is 'grandfather's third cousin', or 'third cousin's grandson', as appropriate, which also gives a sense of the direction as well as the size of the generation gap.

http://www.fhug.org.uk/wishlist/wldispl ... lwlref=445

ID:4079

AdrianBruce · Post by **AdrianBruce** » 23 Nov 2009 14:58

Sounds more sensible - provided it says something like 'Chris' grandfather's third cousin'.

But I think it ought to be switchable because we'll still get asked - 'Are you my third cousin?' (Nearly as chilling as 'Are you my Mummy?' - with apologies to non-Dr Who devotees)

Mind you - just to enter rant mode (not against you Chris!) the fact that someone can't understand something doesn't mean there's ambiguity. I always remember it by saying that the removal is always 'downwards'. Although the problem with the 3C1R notation is (rant /off) you don't know who's on the end of the drop so the TP notation is indeed more helpful.

ChrisBowyer · Post by **ChrisBowyer** » 24 Nov 2009 04:42

My point about it being ambiguous is not that I can't understand it, but that there are at least 2 apparently authoritative but different answers. Unless you know which convention the writer subscribes to, you can't tell what 'twice removed' actually means.

jmurphy · Post by **jmurphy** » 24 Nov 2009 07:10

Chris Bowyer said:But there's a chart on Genes Reunited apparently reproduced from Tracing Your Family History by Anthony Adolph (Collins, revised edition, 2008), which says that if he is my third cousin twice removed, then I am his first cousin twice removed, or his fifth cousin twice removed, depending on whether he's my grandfather's third cousin or I his (I hope you're following this so far).

Chris, would you be kind enough to try the relationship calculator at Steve Morse's One-Step Web Pages http://stevemorse.org/relation/calculator.html and tell me what the results are for your examples? None of my trees are extensive enough to test your cases.

To use the calculator, you press a button to add the relationship as you move along your tree. I started with my husband, and picked out one of the people in the tree whom FH describes as his first cousin three times removed.

She (and her sibs) are my husband's father's father's father's father's sister's children, and Morse's calculator agrees with FH that they are my husband's 1st cousins three times removed.

If I set her as file root in FH instead of my husband, FH still reports her as 1st cousin three times removed.

On Morse's calculator, If I start with her generation and work my way back toward my husband, I build up the relationship by telling it my husband is her mother's brother's son's son's son's son, and it reports again that the relationship is 1st cousin three times removed.

I wonder if the chart reproduced from Anthony Adolph is leading you astray somehow by tracing back to a different common ancestor.

My understanding of how it works is as follows. You trace back to the common ancestor, but to get the numbering right for the cousin relationship, you look for sibling pairs.

If your fathers were brothers, you are first cousins
If your grandfathers are brothers, you are second cousins
If your great-grandfathers are brothers, you are third cousins
-- and so on.

The twice-removed cousin is the grandson of one of those siblings.

I don't see how one can be either a first cousin twice removed, or a fifth cousin twice removed, depending on how you go along the tree. What is the path?

Jan

TimTreeby · Post by **TimTreeby** » 24 Nov 2009 09:43

For all those who are now totally confused about relationships. The Chart Chris refers to takes the Generational Cousinship first and then works the removal, rather than take nearest Cousinship and then take removal. Both of which seem to have a certain logic to them.

See Chart below.

Post by **NickWalker** » 24 Nov 2009 12:33

Jan said:

I don't see how one can be either a first cousin twice removed, or a fifth cousin twice removed, depending on how you go along the tree. What is the path?

Regarding Chris' original post, if you look at the very helpful chart posted by Tim and consider Chris to be the box marked 'ME' on the diagram and you look at the branch on the far right of the tree... what Chris meant was that his example of third cousin twice removed could refer to either the person in the second box down (3rd Cousin Twice Removed) or the one in the 6th box down (3rd Cousin Twice Removed). The relationships back are quite different as the diagram shows in lower case.

Cheers

Nick

Post by **NickWalker** » 24 Nov 2009 12:49

Looking into this further I read the Wikipedia article on cousins (and yes I know that Wikipedia is far from being always right!). There is a useful section called 'Determining cousin type'. It appears that Family Historian is going for a symmetric method, whereas the Genesreunited diagram is using an asymetric method.

Anyway as Chris said it does appear that there are different schools of thought on this!

AdrianBruce · Post by **AdrianBruce** » 24 Nov 2009 18:49

Chris Bowyer said:
My point about it being ambiguous is not that I can't understand it, but that there are at least 2 apparently authoritative but different answers. Unless you know which convention the writer subscribes to, you can't tell what 'twice removed' actually means.

Totally agree with you Chris - just to be clear, no way was I implying you didn't understand something, rather I was suggesting that the asymmetric view of the world was wrong. But if it's out there that much, in places other than that one diagram, then there's no point in me saying it's wrong.

Either way, the TP format sounds a better bet.

(Just don't mention grand-aunts v. great-aunts!)

jmurphy · Post by **jmurphy** » 25 Nov 2009 16:48

Tim's chart is very helpful -- thanks very much!

Nick Walker said:
Jan said:
I don't see how one can be either a first cousin twice removed, or a fifth cousin twice removed, depending on how you go along the tree. What is the path?

Regarding Chris' original post, if you look at the very helpful chart posted by Tim and consider Chris to be the box marked 'ME' on the diagram and you look at the branch on the far right of the tree... what Chris meant was that his example of third cousin twice removed could refer to either the person in the second box down (3rd Cousin Twice Removed) or the one in the 6th box down (3rd Cousin Twice Removed). The relationships back are quite different as the diagram shows in lower case.

Using Morse's calculator:

Starting with ME, and looking at the far right branch as suggested, for the cousin closer to the top of the diagram, the path is my father's father's father's brother's son = 1st cousin twice removed.

Starting with that cousin and going backwards, the path is father's brother's son's son's son = 1st cousin twice removed.

Starting with ME and looking at lower cousin, the path is father's father's father's brother's son's son's son's son = third cousin twice removed. Working backwards from that person, the path is father's father's father's brother's son's son's son which is still third cousin twice removed.

I chose Morse's calculator deliberately for this experiment because it returns multiple answers when multiple answers exist (see the old conundrum 'Brothers and Sisters have I none / But that boy's father is my father's son'). So I suppose the algorithm he uses is the symmetrical one, and I must confess that I just don't grok the asymmetrical model at all.

To me the generations on the tree are like the rungs of a ladder or the floors of a building. Since the tree numbering is upside down from floor numbers let's use the ladder example instead and call them level 1 2 3 4 5, and you have ladder A and ladder B for the two branches. If you go the long way around and climb ladder A up to the lookout point 0 (the common ancestor) and then back down to level 1, you are on level one. And if you go across to ladder B and then climb up to level 1, you still arrive on level 1.

Or in other words, in the symmetrical model, the rule is, the standard 'jump across to the other ladder' usually occurs on the level immediately below the common ancestor -- if you leap across on level three, when you do the removes, you must also SUBTRACT a number from the cousin level to show that you are removing UP rather than DOWN. Unless you do so, you are counting the same 'remove' twice over.

Or am I missing something?

Edited to add: taking the example of the 'Kevin Bacon' game, let's establish a 'cousin number'. Siblings are part of the common ancestor's immediate family and have a cousin number of 0. One takes the cousin number of the closest cousin, then the removes are +n showing the difference in the cousin number between the two.

Edited to add: if someone called a person your 'third cousin's grandfather', as opposed to your 'cousin/removed', that implies to me that you have switched lineages -- assuming that you are related on the paternal line, that would refer to your third cousin's mother's father, rather than your 1C2R

And now that I've completely muddled the waters, I'll get back to work. [wink]

Jan

ChrisBowyer · Post by **ChrisBowyer** » 26 Nov 2009 04:52

jmurphy said:
if someone called a person your 'third cousin's grandfather', as opposed to your 'cousin/removed', that implies to me that you have switched lineages -- assuming that you are related on the paternal line, that would refer to your third cousin's mother's father, rather than your 1C2R

Jan, you're right, 'my 3rd cousin's grandfather' would either imply another line, or it is simply a clumsy way of saying 'my grandfather's first cousin'. My original examples were 'grandfather's third cousin', or 'third cousin's grandson' both of which are 3C2R in the symetric method as used by FH.

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