• Tables for which statistics have not been collected
• Tables where the row count was recorded as 0 in the last statistics collection result
• Tables where the DML workload exceeds 10% of the total row count
• Tables for which a certain period has passed since the last statistics collection period

 select owner, object_name
  from dba_tab_modifications m, (select obj.owner, obj.object_name, dt.row_cnt from _dd_tbl dt, dba_objects obj where dt.obj_id = obj.object_id and obj.object_type like '%TABLE%') t
 where (m.inserts + m.deletes + m.updates > t.row_cnt/10) 
   and t.owner = m.table_owner
   and t.object_name = m.table_name
 order by 1, 2;

 select owner, table_name 
   from dba_tab_statistics 
 where stale_stats = 'YES' 
 order by 2;

4. Tables for which a certain period has passed since the last statistics collection period