Non-functional requirements, such as resource usage and performance are of principal importance because they directly affect costs and benefits of developing and deploying software. However, an approach to object oriented analysis that is use-case driven risks neglecting the analysis of non-functional requirements. A solution to this problem is proposed based on the observation that some non-functional requirements are implemented by functional requirements at a lower level. Trade-off analysis is proposed as a technique to uncover the connection between a non-functional requirement and the objects and methods which realize it, thereby enabling a non-functional requirement to be analyzed within the framework of a use-case realization.