An Early Software Effort Estimation Method Based on Use Cases and Conceptual Classes

It is an important issue in the software industry to predict how much effort will be required for a software project as early as possible. Software size is one of the commonly used attributes in effort estimation. In this paper, we propose an early software size and effort estimation method based on conceptual model of the problem domain. Our method utilizes the noteworthy domain concepts identified mainly from the use cases written in the requirements phase of the software development lifecycle. In order to develop the model and evaluate its prediction quality, the use cases written and the effort data collected for 14 industrial software development projects of a CMMI level 3 certified defense industry company have been used. Evaluation results reveal a high correlation between the number of conceptual classes identified (i.e., domain objects) during the requirements analysis, the number of classes constituting the resulting software and the actual effort spent. Moreover, we have used the use case point (UCP) method to estimate the effort needed for each project and compared the results of UCP analysis with the results obtained with our method. The comparisons have shown that, for the projects considered, our method gives a better effort estimation compared to the effort estimated by using the UCP method