quercus23,

note that:

" " as per se1429 formula is in fact a Space as opposed to a traditional Null value which would be ""

=IF(ISBLANK(J3),"",IF(J3>H3,"Yes","No"))

Also depending on how J3 is populated it may be you'd want to use:

=IF(ISNUMBER(J3),IF(J3>H3,"Yes","No"),"")