- Period (Currency): Restricted. The tradition of building and using Enclosed Oppida appears from present evidence to have spanned between 150 and 300 years, broadly the 3rd century BC to the mid 1st century AD. Individual sites were used throughout most of this period.
- Rarity: Very rare. Only about 10 examples are known, although it is likely that further aerial reconaissance and fieldwork may add to this number.
- Diversity (form): Medium. Given the lack of excavated information, assessment of diversity is problematic. Here it is suggested that on morphological and locational grounds alone, three main types can be isolated.
- Period (representativity): High. Enclosed Oppida are one of a fairly restricted range of monument classes known for the later Prehistoric period. They also yield a wide range of cultural material.
Assigning scores to these criteria following the scheme set out in the Monuments Evaluation Manual, enclosed oppida yield a class importance value of 33. This places the class roughly half way up the range of possible values (max= 64), emphasising the rarity and representativity of the class.