Data-structure.md

@@ -47,9 +47,9 @@ PEP provides a number of predefined column groups and participant groups. Their
 
 # Step by step
 
-Several parties are involved in determining PEP's data structure.
+PEP's data structure depends on the actions of different parties:
 
-- Column management is performed by different parties:
+- Column management is performed by different parties, depending on the specific column:
     - Some of PEP's columns are predefined and automatically created when a PEP environment is provisioned.
     - The PEP (support) team manages an environment's basic configuration. Short pseudonym columns are created (and removed) as a result.
     - Data Administrator can create and remove columns by means of [the `pepcli ama column` command](Using-pepcli#ama-column).