The method of the present invention to re-factor, rationalize, and prioritize a service model and to assess service exposure in the service model is illustrated. The service model is reviewed and re-factored and the service portfolio and service hierarchy are refined, exposure decisions are made, and finally the service model and its constituent parts are rationalized based on the re-factoring and exposure decisions. Another technique called Service Litmus Tests (SLTs) is leveraged during service re-factoring and rationalization. SLTs are set of gating criteria to select and filter a set of (candidate) services from the service portfolio for exposure. A Service Exposure Assessment Toolkit (SEAT) is also presented in the present invention. SEAT is a mathematical model to facilitate making exposure decisions for services and prioritizing the services in the service model.