The four criteria for assessing class importance apply to tor cairns as follows:
- Period (currency): Extended. The tradition of building and using tor cairns is not fully documented, but seems to have spanned most if not all the early Bronze Age and perhaps some of the middle Bronze Age, maybe as much as four or five centuries.
- Rarity: Very rare. On a national scale tor cairns must be regarded as a very rare class of monument. It is estimated that between 40 and 50 more or less certain examples have been recorded to date, although it is likely that this number will rise as the class as a whole is better recognized.
- Diversity (form): Low. On the basis of present evidence only two main types of tor cairn can be identified.
- Period (representativity): High. Tor cairns are one of relatively few classes of monuments characteristic of the early and middle Bronze Age. They seem to reflect a particular kind of relationship between ceremonial activity and the landscape, even though the full nature of that relationship is not currently understood. The range of artefacts represented at excavated examples is considerable.
Assigning scores to these criteria following the system set out in the Monument Evaluation Manual, tor cairns yield a Class Importance Value of 35. This lies over half-way up the range of possible values (max.= 64) reflecting the rarity and postulated longevity of the tradition. Examples representing both main types, and variations in size and situation, must also be included in the sample of nationally important sites.