Hi everyone

I have a data set in which each observation should be uniquely identified by a combination of two variables - a school number and a serial number within each school. However, due to problems with the data entry process, there are a number of observations with duplicate values for the combination of school and serial numbers.

I would like to be able to compare the school and serial numbers for each observation with those from the previous observation and then output *both* observations to a data set if they are duplicated. I can use a retain statement to define variables that will carry the school and serial numbers over iterations of the data step to allow the comparison but, as SAS appears to work on an observation by observation basis only, I can't figure out how to output both observations. Can anyone offer a simple solution?

Thanks for any help.

Tadd

-- Tadd Clayton Ph: 64 9 373 7599 ext. 6451 Research Officer Fax: 64 9 373 7486 Department of Paediatrics Email: t.clayton@auckland.ac.nz School of Medicine University of Auckland Private Bag 92019 Auckland NEW ZEALAND