A good way to understand why a formla does not return expected result is to
select part of it and press F9, which then replaces the formula by its
result. In your case, if you select the OR(...) part, you see that Excel does
not like it very much. May be it is because of the missing quotes around the
second argument? No, still no luck.

In fact OR function only works with numbers, so in your case you should
proceed differently and add two SUMIF:
=SUMIF(Reason,"B Scale",M20:M33) + SUMIF(Reason,"B Scale Night",M20:M33)



"Barb" wrote:

=SUMIF(Reason,(OR("B Scale",B Scale Night)),M20:M33)

I am trying to sum cells in column M20:M33 if the named cells "Reason"
contain the words "B Scale" or "B Scale Night"

What am I doing wrong?