1. A method of assigning contact center agents to groups, the method performed by a processor in a computing system of a contact center, comprising the steps of: (a) maintaining, for a set of contact center agents associated with a contact center, performance data relating to the activities of the contact center agents; (b) specifying one or more performance metrics against which the performance data of the contact center agents may be evaluated by specifying a number, n, of performance metrics P in numerical form as a set of values (p 1 , p 2 ,. .. p n ), and further comprising expressing, for each of the plurality of agents, a corresponding set of performance data Q in numerical form as a set of values (q 1 , q 2 ,. .. q n ); (c) determining an evaluation score for each of a plurality of the contact center agents against the performance metric(s) based on the performance data by evaluating for each agent the expression: S = ∑ i = 1 n ⁢ ⁢ c i ⁡ ( q i - p i ) 2 wherein c i represents a weighting constant; and (d) assigning the plurality of contact center agents among a plurality of agent groups according to each agent's respective evaluation score.