DISTBY replication-id-variable;
A DISTBY statement is necessary if and only if you specify an ID= variable in the EXTERNALCOUNTS statement. In fact, the replication-id-variable must be the same as the ID= variable. This is required for correct simulation of the CDM in the presence of the ID= variable.
The replication-id-variable must not appear in the BY statement. However, the DATA= data set must be sorted as if the replication-id-variable were listed after the BY variables in the BY statement.