1. A system for modeling and evaluating impact on service components, comprising: a processor operable to present a UML sequence diagram describing service components and flow of transactions between the service components, the processor further operable to enable entering information associated with the UML sequence diagram in a distinct and separate step from generating the UML sequence diagram, the processor further operable to derive a Markov model from the UML sequence diagram and entered information, wherein the Markov model includes a plurality of states and state transition probabilities representing the flow of transactions between the service components; and wherein the processor is further operable to automatically compute the state transition probabilities from the sequence diagram.