Open Record Step 8: Interrogate the Source

Answer all five questions in writing for your dataset, in your sources file. Then find one thing the data cannot tell you and write that down too, specifically rather than generally: not 'the data is incomplete' but 'this covers only registered addresses, so anyone without one is absent'. If you cannot find a gap, you have not read the documentation closely enough. Every dataset has one, and the ones that seem not to are usually hiding it in the collection method.