Howdee all.
I was just presented with a problem that has got me curious.
While it's something I have thought about before, I never knew where to
begin with it.
I have two data sheets. Each have names, values, etc...-- one is a source
sheet, and the second is a summary sheet of the source data.
On the Summary sheet, I have a bunch of sumproduct functions with two
criteria arrays, and one sum array. At times I'm short a name or two, and
must manually work through my source sheet to identify a name that's missing
on my Summary sheet (As you might imagine, it's a pain-staking process for
longer data-sets).

What I want to do is to set up a function that will look at all the names on
the source sheet, and compare them to the summary sheet names. If a name is
missing on my summary sheet, I want to have it tell me the name that's
missing.

I've used Match(), if(), and maybe one or two others (that I can't remember
at the moment) to try this, and Match just tells me if the name doesn't
exist-- #N/A error.

Does anyone have an idea on either a single worksheet function, or a
combination of nested worksheet functions to accomplish this?

I don't care where the name is on my source sheet-- just if I've missed
having it on my summary sheet-- and what the name actually is.

Thank you for your helps-- in advance.
Best.