How about something like:

=SUMPRODUCT(--(Main!$C$2:$C$266=$C11),Main!$FF$2:$FF$266)/SUMPRODUCT(--(Main!$C$2:$C$266=$C11),--(Main!$FF$2:$FF$266<""))

HTH
Elkar


"Andrew" wrote:

I am trying to reduce a large dataset of 266 individuals of 23 species into
one that just includes the means of each species. Species names are text
entries in column C. There are some missing data points, so I could not
simply use:
=SUMIF(Main!$C$2:$C$266,$C11,Main!FF$2:FF$266)/COUNTIF(Main!$C$2:$C$266,$C11)
because the countif is not counting the exact cells going into the sum.

So my current approach is to use DAVERAGE. I am specifying the
worksheet(Database?), column, and criteria. The criteria compares text in
the 2 columns

Daverage(Main!1:65536,FF$2:FF$266,Main!$C$2:$C$266 =$C11)
however, I am getting a #VALUE error.
any help, thanks