Component reuse metrics - assessing human effects

A new method for estimating the software development effort, Component Reuse Metrics, CRM, developed in this study, combines the best means of object-oriented component technology and the analysis of human behaviour into simple calculation rules. CRM uses the component structure of the products, which can be obtained from a CASEtool or from a configuration management system as a base for the effort calculations. CRM describes the software size by the numbers of different kinds of components, but it notices that these numbers are not additive. There are two component structures, the external customer's view and the internal implementation view, which are connected tightly together. In component based development each component is assembled to a product using one or more standard human tasks defined by the development process. Because this project work breakdown structure is tightly connected to the component structure, the effort of a component can be calculated by using the history data of the previous projects. CRM calculates the optimal effort for each of these tasks in the accomplished projects by reassessing and subtracting the human effects. This optimal effort is used in the estimation of the future projects. It is achieved when a highly skilled and motivated person without a need for teamwork or any risk accomplishes the task. CRM classifies the human effects as skill effect, motivation effect, team effect and risk effect and produces subtasks of the original task for each of them. The skill effect takes the required training into the calculations and motivation effect assesses the effect of the motivation of the staff to the development effort. The effort needed in sharing information is included in the team effect. The most important risk, the additional features added to the product during the development, is taken out of the risk effect, which is otherwise calculated as an probable additional effort of a task. This feature creep effect can be revealed from the difference of the original and final component structure