Yes, you are right. i just checked using some if- then statements.. there is not a single case with missing data for PR1. i would like to know if you think,, the following program is right for the same above purpose about the missing data? option missing= ' '; However this shows me one missing case.. data library.nismicathcabg4; set library.nismicathcabg4; array dxtrialpci{15} pr1-pr15; pcitrial=0; do i=1 to 15; if dxtrialpci{i} in ('0066', '3604', '3606', '3607') then pcitrial=1; end; if n (pr1, pr1, pr3, pr4, pr5, pr6, pr7, pr8, pr9, pr10, pr11, pr12, pr13, pr14, pr15)=0 then pcitrial=. ; run; Thanks, Ashwini
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