The four criteria for assessing class importance apply to slight univallate hillforts as follows:
- Period (currency): Long-lived. The dates for slight univallate hillforts span a 700 year period between the 12th and 6th centuries BC. In south-west England the currency of this class of monument may extend over a period of around 1200 years. Dating evidence is very limited, but suggests that examples in this region may have been constructed and used up to the mid-1st century BC.
Activities within individual sites appear to have spanned a much shorter period. The majority of dated sites seem to have been occupied during the early Iron Age for a maximum of 200 years. The evidence suggests that some of the later Bronze Age sites were used over a longer period of up to 400 years, although they may not have been defended during early phases of occupation.
- Rarity: Rare. An estimate based upon published sites suggests that around 150 slight univallate hillforts have been recorded. Although on a national scale the number is low, in Devon they comprise one of the major classes of hillfort. In other areas where the distribution is relatively dense such as Wessex, Sussex, the Cotswolds and the Chilterns, hillforts belonging to a number of different classes occur in the same region.
Examples are recorded in eastern England, the south-west peninsula, the Welsh Marches, and central and northern England, but are very rare in comparison with other classes of hillfort and defended settlement.
- Diversity (types): Very high. It is recommended that types of slight univallate hillforts should be defined according to two factors (see Section 3 and Figure 1). From the first, which takes into account the development of individual sites, three main types of slight univallate hillfort have been distinguished. Also relevant is the structure of the ramparts which can occur in eight possible forms. When the two factors are combined 16 possible permutations emerge.
Further variation has been noted in shape, although this has not been used to establish a type series since it appears in many cases to be a function of local topography.
- Period (representativity): Medium. Slight univallate hillforts represent one of a relatively large range of monument classes known to characterize the late Bronze Age and early Iron Age. This may vary in some regions where the total number of recorded monument classes for this period is much lower.
Assigning scores to these criteria following the system set out in the Monument Evaluation Manual, slight univallate hillforts yield a Class Importance Value of 45. This lies well within the upper half of the range of possible values (max. = 64). In selecting examples which are of national importance it is important to include sites which represent a variety of topographic, geological and regional situations. A representative sample of the types defined above is also desirable, while examples of different date should be included wherever possible.