I think it's the reverse. Without any reference to accepted practice  
 or even to EAD markup in particular  the markup included implies  
in the first example, that there's some conceptual entity 'did' that  
has as it's content something called  'unitdate.'  The concept of  
unittitle doesn't exist.

In the second example, 'did' contains 'unittitle,' the content of  
which is 'unitdate.'  So the value of unittitle is the value of it's  
child: "1915-1920."

This seems pretty obvious to my mind, and it illustrates the  
difference between semantic markup versus markup that suits some  
other purpose, like formatting or just delimiting data fields, say.

I would agree, though, that these have no semantic difference:


Both share the same value and both have the same hierarchy.

On Mar 28, 2012, at 8:42 AM, Michael Fox wrote:

> There is no semantic difference between
> <did>
>      <unitdate>1915-1920</unitdate>
> </did>
> and
> <did>
>      <unittitle><unitdate>1915-1920</unitdate></unittitle>
> <did>
> except that your institution has unilaterally decided there is one  
> as you explained.   That's fine but it does not signify in an  
> exchange enviroment where others do not know or share your convention.

Brian Sheppard
University of Wisconsin Digital Collections Center
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