The State Historic Preservation Office (SHPO) creates the framework for the inventory process in Oregon. These guidelines are regularly updated; therefore cities may have a collection of different inventory forms that include slightly different or, in some cases, more detailed information. These forms are cumulative in nature; a new form does not overtake an older form. Together, they paint a picture of the evolution of the building, and depending, upon the type of inventory form used, different information will be presented. If a structure is designated, the inventory form provides background about what features made it suitable for designation and can be updated as needed or required. An omission or incorrect detail in an inventory form does not bind the city to a certain outcome as a land use action might. Rather, they are informative and provide relevant context to future land use decisions.
The electronic version of the SHPO Survey Guidelines can be found on the Oregon SHPO Inventory Guidelines page.