ok, I still think I shouldn't have to use a variable since I can reference the dataset in my expression box like so.

=Switch(Fields!row_description.Value = "Follow-Up Score", AVG(Fields!score.Value),

Fields!row_description.Value = "% Leads Referred", count(Fields!ref.Value, "results") / count(Fields!lead_id.Value, "lead_unfiltered"),

True, Count(Fields!lead_id.Value))

the ref.value is always a 1 or 0, and the lead_id.value is an id....which is why Count against the columns directly should work (IMO). I will mess with it a bit more before I delve into using a variable....seems so close, plus have no idea how to create Variables in SSRS. Would be first time. Have created parameters though.