Using Excel 2003 I have this formula to count the number of times the
physicians name occurs between two dates:
=SUMPRODUCT(--(Date=3/1/2010),--(Date<=3/31/2010),--(Physicians="Smith")).
Date refers to a named range of cells in column A. Physicians refers to a
named range of cells in column E. I am getting this value error message, "A
value used in the formula is of the wrong data type." What needs to be
changed? Thank you for your assistance.