Software Effort Estimation with Multiple Linear Regression: Review and Practical Application

Software development effort estimation is the basis for the effective project planning and scheduling as well as for the project's budget definition. This article describes the most common methods used in the software effort estimation (SEE) and presents the study performed in a software development organization (SDO) that is implementing the software development process improvement framework Capability Maturity Model Integrated (CMMI). Currently SDO estimates the software effort based on the opinion of one area expert. The disadvantages of this method and the willingness to incorporate the best practices of CMMI encouraged the SDO to replace the existing effort estimation method by a formal one. The stepwise Multiple Linear Regression (MLR) technique was selected and used for the software development and software testing processes. The results achieved with MLR were compared with the estimates provided by the area expert. The model obtained for the testing team performed better results than the expert judgments, while for the development team no satisfactory model was found and a proposal for collecting data from new variables is presented.