The four criteria for assessing class importance apply to artillery castles as follows:

Period (currency): Transient. The tradition of building this class of castle lasted for about 80 years, starting in 1481, most being built between 1539 and 1545, and the last in 1559-62.

Rarity: Very rare. A total of 21 sites are known; the number is unlikely to increase as most have probably been identified in some way.

Diversity (form): Very high.The classification proposed above illustrates the wide diversity of this class of monument.

Period (representativity): Medium. Artillery castles were one of a wide range of classes of similar date. There are however relatively few related to defence, and it may be noted that the construction methods used and some of the detailing shown are important elements of the period.

Assigning scores to these criteria following the system set out in the Monument Evaluation Manual, artillery castles yield a Class Importance Value of 41. This is two thirds up the range of possible values, (max. 64), reflecting the wide diversity and rarity of this class of monument.