The OSA Archaeological Manual divides archaeological surveys into phases, which are determined by management objectives and standard archaeological practice.
Phase 1 surveys utilize basic reconnaissance techniques to locate sites within project areas. Phase 1 work can prevent effects to sites caused by development projects, eliminating the need for Phase 2 and Phase 3 work. The purpose of Phase 2 surveys is usually to evaluate the importance of sites, and if necessary, to better characterize the site for implementation of a data recovery plan -- which would be done as a Phase 3 project.
All phases of archaeological fieldwork are preceded by a Literature Search. A literature search examines standard references in order to summarize what has been written and what is known about a given area or topic without the necessity of fieldwork. Most literature searches are performed prior to undertaking fieldwork, but may be expanded during or after fieldwork.
Literature searches can be used to do the following:
Help assess the need for survey and what methods should be employed
Develop site locational models
Determine areas of previous terrain disturbance or land-use
Provide historic context to help evaluate site significance
Provide background information for developing data recovery plans
Provide sufficient information for National Register nominations or site interpretation
A literature search is synonymous with a records search or archival research, although literature searches can and, in some cases, should involve oral interviews with appropriate individuals such as landowners, local artifact collectors, and topical experts.