Since those formulas are exactly the same, I'd guess that you didn't array enter
one of them or maybe your data doesn't contain enough numeric data.

maybe wrapping your formula with a check:

=if(count($r$4:$R$39)<a05,"not enough numbers",.....

Brad wrote:

I have two worksheets that are identical in the same workbook

=SMALL(IF(MATCH($R$4:$R$39,$R$4:$R$39,0)=ROW($R$4: $R$39)-CELL("Row",$R$4:$R$39)+1,$R$4:$R$39),AO5)

works just fine on the first worksheet as an array formula

But
=SMALL(IF(MATCH($R$4:$R$39,$R$4:$R$39,0)=ROW($R$4: $R$39)-CELL("Row",$R$4:$R$39)+1,$R$4:$R$39),AO5)

Doesn't work on the second worksheet as an array formula

What am I doing wrong??

--

Dave Peterson