In embodiments of the invention, a system receives selections from a user based on a list of pre-defined monitoring categories and/or optionally receives custom category definitions from the user. The option for custom category definitions may be advantageous due to the flexibility provided to a system administrator or other user. In embodiments of the invention, the pre-defined and/or custom monitoring categories may be or include complex hierarchical behavior. Such an approach provides monitoring algorithms that can achieve improved accuracy compared to known methods. In embodiments of the invention, the order of computations used in resolving a monitoring category may be re-ordered, statically and/or dynamically, to improve the efficiency of monitoring operations.