All heritage assets derive their significance from the same set of heritage values. What separates national and local heritage assets is the importance of those values. Assets of high significance are more likely to be nationally listed. For assets that are not nationally listed, a local list can be used to assess and record their heritage values.

Dorset’s local heritage assets are assessed using a combination of heritage values from the National Planning Policy Framework and Historic England’s Conservation Principles, Policies and Guidance. In line with the Department for Digital, Culture, Media & Sport's guidance on the Principles of Selection for Listed Buildings, nominations for the local list must be at least 30 years old. Under exceptional circumstances a case may be made for younger assets, but their local interest would need to be outstanding in multiple values.