The Research And Application Of COSMIC Method Objectivity Risk Evaluation Method

Software project size measurement is always a complicated matter because of software's natural complexity, lack of historical experience, shortage of estimation tools and some artificial mistakes, the size estimation of software project is always far away with actual instance. The COSMIC method studied in the paper, based on conception and measurement rules of COSMIC method, mapping functional requirement of system into measurement model, decomposing functional requirement into a serial of function processes, function process includes four type data movement. Through gathering data movements of all function processes, we can get the overall size of system.Comparing with other function point method, it has obvious advantages. However, COSMIC method has some limitations. Mainly representing: process described in the COSMIC method measurement manual is too general, leads to the more complex use in practice, ease of use is relatively poor, the basic concept is more abstract, and in the process of method mapping into technology, with the greater ambiguity, have impact on the objectivity of the method of application and further affect the accuracy of the size measurement.Through researching and applying COSMIC method, facing these problems of measurement process of COSMIC method, combining thinking of risk management and we made COSMIC Risk Management (COSMIC Risk Management, CRM) framework, the framework includes risk identification and analysis, making risk resolve plan and monitoring risk; Firstly, we used WBS breakdown technology to identify risk, according to measurement process of COSMIC method, breakdown and analyze risk; Secondly, we made risk resolve plan based on risk, give some resolves to each risk. Further, we used risk checklist to monitor risk, risk checklist is used to check all measurement process. Under the guidance of CRM framework, we combined risk checklist to measure size, by comparing and analyzing two measurement result, we found CRM framework avoids or mitigates the objectivity risk of the COSMIC method application to a certain extent. Finally, we further analyzed some important problems in the field of software estimation, to illuminate these problem need estimator'attention by analyzing; And we made a simple forecast and hope for the future development direction of Function Point method, we hope software size measurement will be developed and more perfect and provide a favorable base for successful development of software project.