Checked against the source, not assumed.

First the universe is defined, then it is measured, then it is built. Columns are standardised to one definition each, and the original kept beside it. You can tell, from the file alone, what was checked and what was assumed.

• Repeat control

  Removing duplicates within the file and against anything previously supplied to you.

• Field standardisation

  One definition per column, applied consistently, with original values retained beside the normalised ones.

• Completeness testing

  Checking which columns are populated and to what degree, before handover rather than after it.