Hi

You just need to add another argument to your existing function:
=SUMPRODUCT(--('Talk Log'!C4:C61=C4),--('Talk Log'!C4:C61<=D4),--(Talk
Log'!D4:D61))
where your attendees totals are in column D alongside the dates.

--
Andy.


"Dummies isn't any good"
wrote in message ...
Guys and gals,

Apologies for this being simple to some, but what I want to do sounds
simple
in theory. I've got to make a spreadsheet to track when talks were given
and
how many attended, and this data will be broken up into periods of the
year.
So far, I've got something like this

Talk Title......Date Given......Number attendees

On another worksheet I've used a sumproduct to work out how many talks
took
place in one period (eg. 1/3/2005-28/3/2005) but now I want to be able to
take the number of attendees and correlate it with specific periods. Below
is
an example of the sumproduct calculation:

=SUMPRODUCT(--('Talk Log'!C4:C61=C4),--('Talk Log'!C4:C61<=D4))

As you can see, it works out how many talks took place in specific periods
(C4 and D4 just have dates in them), what I need to do is take the dates
mentioned and add up the number of people who went on the talks, any
ideas???????? Thanks for even reading this by the way!