When it has been established by a desk based assessment that an evaluation of a site is necessary then a supplementary field inventorization can be carried out with test-trenches (IVO-P) or boreholes (IVO-b). Test –trenches are placed according to a strategy developed out of the expected value of the site coupled with knowledge of its ground profile and accessibility.
In the trenches the disturbed top layer and subsequent layers are removed gradually by ‘shaving’ so that finds can be collected per level. Traces in the plane of each level can give information on where poles used to be or ditches. On the basis of these a trench may be expanded or extra trenches dug with as goal determining the extent of a cluster of traces or a structure. Traces and finds are measured and documented though not, in principle, dug out in this case. However, a number of significant ones are indeed excavated with the goal of dating and establishing their nature and quality of finds. From a few of these samples are taken for specialist treatment (botany, phosphates etc). The pit-profiles and traces are all documented in drawings and photos. Afterwards the soil can be returned to the trench and the surface leveled.
All of this delivers a report of what was found: traces, finds and their evaluation and recommendations concerning possible further follow-up research.