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 .