bradford factor

Traditional Frequency Array would be along the lines of:

K1:
=IF(COUNTIF($A1:$H1,"sick")=0,0,SUM(SIGN(FREQUENCY(IF($A1:$H1="sick",COLUMN($A1:$H1)),IF($A1:$H1<>"sick",COLUMN($A1:$H1))))))
confirmed with CTRL + SHIFT + ENTER (enter alone will not suffice)
copied down

Originally Posted by 6StringJazzer

BTW the documentation on array formulas isn't that good, and I have never seen a really good explanation of how they work.

I would suggest reading through Colin Legg's Tutorial - linked in my Sig (Arrays) - pretty extensive IMO.