When archaeology conditions appear on a planning consent, applicants often ask which kind of fieldwork will follow. The three terms heard most often are watching brief, evaluation and excavation, but they are not interchangeable. Each one serves a different purpose, and the type required depends on how much is already known about the site and how significant the likely archaeology may be.
A Written Scheme of Investigation, usually shortened to WSI, is the document that sets out how archaeological work will be carried out on a site. It is commonly prepared once planning permission has been granted with archaeology conditions, or when a defined programme of archaeological work needs to be agreed in advance. In simple terms, it is the method statement that explains what will happen, why it is needed and how the work will meet the planning requirement.