1. A method for assessing the relative complexity of different options for performing a task, the method comprising the steps of: defining the task as a sequenced set data structure that specifies actions of the task, and sequence information that specifies the order in which particular actions are to be performed; storing recipes available for performing constituent actions of the task as sequenced set data structures that specify subactions of the recipes for the constituent actions, and sequence information that specifies the order in which the subactions are to be performed; and determining complexity measures associated with performing the task using different combinations of recipes for constituent actions of the task, based upon complexity measures of actions specified by respective combinations of available recipes.