A desk-based assessment (DBA) is done before any kind of evaluation in the field is carried out and can arise for a number of reasons.
The DBA is rarely the only planning condition required, it is the first phase of what is called a nested programme of works, where each phase builds on the previous phase to gather the information for a planning application decision. Having a DBA carried out as
soon as possible can help avoid unexpected problems and expensive delays.
The purpose of the DBA is to collate information to assess the presence, significance and quality of known archaeology on the site
or area, and the potential for previously unknown archaeology being present. This information is gathered and synthesised from sources such as historic maps and documents, the local SMR, Local History Centre archives, and aerial photographs. The strategy for any further phases of work is then informed by the DBA. In most cases the next phase will be fieldsurvey, evaluation, mitigation, or a full programme of works.